Paint it Black by the Rolling Stones (#920)

7 files changed, 891 insertions, 605 deletions

diff --git a/tests/conftest.py b/tests/conftest.py
index 366624e..5bae6b8 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -12,7 +12,7 @@ def pytest_report_header(config):
 
     return "OpenSSL: {openssl}\ncryptography: {cryptography}".format(
         openssl=OpenSSL.SSL.SSLeay_version(OpenSSL.SSL.SSLEAY_VERSION),
-        cryptography=cryptography.__version__
+        cryptography=cryptography.__version__,
     )
 
 
diff --git a/tests/memdbg.py b/tests/memdbg.py
index 6e608a7..590b72d 100644
--- a/tests/memdbg.py
+++ b/tests/memdbg.py
@@ -5,8 +5,8 @@ import traceback
 from cffi import api as _api
 
 
-sys.modules['ssl'] = None
-sys.modules['_hashlib'] = None
+sys.modules["ssl"] = None
+sys.modules["_hashlib"] = None
 
 
 _ffi = _api.FFI()
@@ -16,18 +16,22 @@ _ffi.cdef(
     void free(void *ptr);
     void *realloc(void *ptr, size_t size);
 
-    int  CRYPTO_set_mem_functions(void *(*m)(size_t),void *(*r)(void *,size_t), void (*f)(void *));
+    int  CRYPTO_set_mem_functions(
+        void *(*m)(size_t),void *(*r)(void *,size_t), void (*f)(void *));
 
     int backtrace(void **buffer, int size);
     char **backtrace_symbols(void *const *buffer, int size);
     void backtrace_symbols_fd(void *const *buffer, int size, int fd);
-    """)  # noqa
+    """
+)  # noqa
 _api = _ffi.verify(
     """
     #include <openssl/crypto.h>
     #include <stdlib.h>
     #include <execinfo.h>
-    """, libraries=["crypto"])
+    """,
+    libraries=["crypto"],
+)
 C = _ffi.dlopen(None)
 
 verbose = False
@@ -80,8 +84,8 @@ def free(p):
 
 
 if _api.CRYPTO_set_mem_functions(malloc, realloc, free):
-    log('Enabled memory debugging')
+    log("Enabled memory debugging")
     heap = {}
 else:
-    log('Failed to enable memory debugging')
+    log("Failed to enable memory debugging")
     heap = None
diff --git a/tests/test_crypto.py b/tests/test_crypto.py
index 2a0c967..75f4a5a 100644
--- a/tests/test_crypto.py
+++ b/tests/test_crypto.py
@@ -26,7 +26,7 @@ from OpenSSL.crypto import (
     X509Store,
     X509StoreFlags,
     X509StoreContext,
-    X509StoreContextError
+    X509StoreContextError,
 )
 from OpenSSL.crypto import X509Req
 from OpenSSL.crypto import X509Extension
@@ -40,7 +40,11 @@ from OpenSSL.crypto import PKCS12, load_pkcs12
 from OpenSSL.crypto import CRL, Revoked, dump_crl, load_crl
 from OpenSSL.crypto import NetscapeSPKI
 from OpenSSL.crypto import (
-    sign, verify, get_elliptic_curve, get_elliptic_curves)
+    sign,
+    verify,
+    get_elliptic_curve,
+    get_elliptic_curves,
+)
 
 from .util import EqualityTestsMixin, is_consistent_type, WARNING_TYPE_EXPECTED
 
@@ -162,7 +166,8 @@ h0VtBuQoHPtjqZXF59oX6hMMmGLMs9pV0UA3fJs5MYA4/V5ZcQy0Ie0QoJNejLzE
 -----END CERTIFICATE-----
 """
 
-server_key_pem = normalize_privatekey_pem(b"""-----BEGIN RSA PRIVATE KEY-----
+server_key_pem = normalize_privatekey_pem(
+    b"""-----BEGIN RSA PRIVATE KEY-----
 MIICWwIBAAKBgQC+pvhuud1dLaQQvzipdtlcTotgr5SuE2LvSx0gz/bg1U3u1eQ+
 U5eqsxaEUceaX5p5Kk+QflvW8qdjVNxQuYS5uc0gK2+OZnlIYxCf4n5GYGzVIx3Q
 SBj/TAEFB2WuVinZBiCbxgL7PFM1Kpa+EwVkCAduPpSflJJPwkYGrK2MHQIDAQAB
@@ -177,7 +182,8 @@ FwwOhpahld+vqhYk+pfuWWUpQciE+Bu7ZQJASjfT4sQv4qbbKK/scePicnDdx9th
 NaeNCFfH3aeTrX0LyQJAMBWjWmeKM2G2sCExheeQK0ROnaBC8itCECD4Jsve4nqf
 r50+LF74iLXFwqysVCebPKMOpDWp/qQ1BbJQIPs7/A==
 -----END RSA PRIVATE KEY-----
-""")
+"""
+)
 
 intermediate_server_cert_pem = b"""-----BEGIN CERTIFICATE-----
 MIICWDCCAcGgAwIBAgIRAPQFY9jfskSihdiNSNdt6GswDQYJKoZIhvcNAQENBQAw
@@ -229,7 +235,8 @@ JRgjHbWutZfZvbSHXr9n7PIphG1Ojg==
 -----END CERTIFICATE-----
 """
 
-client_key_pem = normalize_privatekey_pem(b"""-----BEGIN RSA PRIVATE KEY-----
+client_key_pem = normalize_privatekey_pem(
+    b"""-----BEGIN RSA PRIVATE KEY-----
 MIICXgIBAAKBgQDAZh/SRtNm5ntMT4qb6YzEpTroMlq2rn+GrRHRiZ+xkCw/CGNh
 btPir7/QxaUj26BSmQrHw1bGKEbPsWiW7bdXSespl+xKiku4G/KvnnmWdeJHqsiX
 eUZtqurMELcPQAw9xPHEuhqqUJvvEoMTsnCEqGM+7DtboCRajYyHfluARQIDAQAB
@@ -244,7 +251,8 @@ si6xwT7GzMDkk/ko684AV3KPc/h6G0yGtFIrMg7J3uExpR/VdH2KgwMkZXisSMvw
 JJEQjOMCVsEJlRk54WWjAkEAzoZNH6UhDdBK5F38rVt/y4SEHgbSfJHIAmPS32Kq
 f6GGcfNpip0Uk7q7udTKuX7Q/buZi/C4YW7u3VKAquv9NA==
 -----END RSA PRIVATE KEY-----
-""")
+"""
+)
 
 cleartextCertificatePEM = b"""-----BEGIN CERTIFICATE-----
 MIIC6TCCAlKgAwIBAgIIPQzE4MbeufQwDQYJKoZIhvcNAQEFBQAwWDELMAkGA1UE
@@ -266,7 +274,8 @@ lEqxh3aFEUx9IOQ4sgnx1/NOFXBpkRtivl6O0Ec=
 -----END CERTIFICATE-----
 """
 
-cleartextPrivateKeyPEM = normalize_privatekey_pem(b"""\
+cleartextPrivateKeyPEM = normalize_privatekey_pem(
+    b"""\
 -----BEGIN RSA PRIVATE KEY-----
 MIICXQIBAAKBgQD5mkLpi7q6ROdu7khB3S9aanA0Zls7vvfGOmB80/yeylhGpsjA
 jWen0VtSQke/NlEPGtO38tsV7CsuFnSmschvAnGrcJl76b0UOOHUgDTIoRxC6QDU
@@ -282,7 +291,8 @@ ttXigLnCqR486JDPTi9ZscoZkZ+w7y6e/hH8t6d5Vjt48JVyfjPIaJY+km58LcN3
 6AWSeGAdtRFHVzR7oHjVAkB4hutvxiOeiIVQNBhM6RSI9aBPMI21DoX2JRoxvNW2
 cbvAhow217X9V0dVerEOKxnNYspXRrh36h7k4mQA+sDq
 -----END RSA PRIVATE KEY-----
-""")
+"""
+)
 
 cleartextCertificateRequestPEM = b"""-----BEGIN CERTIFICATE REQUEST-----
 MIIBnjCCAQcCAQAwXjELMAkGA1UEBhMCVVMxCzAJBgNVBAgTAklMMRAwDgYDVQQH
@@ -359,7 +369,8 @@ Ho4EzbYCOaEAMQA=
 -----END PKCS7-----
 """
 
-pkcs7DataASN1 = base64.b64decode(b"""
+pkcs7DataASN1 = base64.b64decode(
+    b"""
 MIIDNwYJKoZIhvcNAQcCoIIDKDCCAyQCAQExADALBgkqhkiG9w0BBwGgggMKMIID
 BjCCAm+gAwIBAgIBATANBgkqhkiG9w0BAQQFADB7MQswCQYDVQQGEwJTRzERMA8G
 A1UEChMITTJDcnlwdG8xFDASBgNVBAsTC00yQ3J5cHRvIENBMSQwIgYDVQQDExtN
@@ -378,7 +389,8 @@ bYIBADANBgkqhkiG9w0BAQQFAAOBgQA7/CqT6PoHycTdhEStWNZde7M/2Yc6BoJu
 VwnW8YxGO8Sn6UJ4FeffZNcYZddSDKosw8LtPOeWoK3JINjAk5jiPQ2cww++7QGG
 /g5NDjxFZNDJP1dGiLAxPW6JXwov4v0FmdzfLOZ01jDcgQQZqEpYlgpuI5JEWUQ9
 Ho4EzbYCOaEAMQA=
-""")
+"""
+)
 
 crlData = b"""\
 -----BEGIN X509 CRL-----
@@ -606,8 +618,8 @@ class TestX509Ext(object):
         # This isn't necessarily the best string representation.  Perhaps it
         # will be changed/improved in the future.
         assert (
-            str(X509Extension(b'basicConstraints', True, b'CA:false')) ==
-            'CA:FALSE'
+            str(X509Extension(b"basicConstraints", True, b"CA:false"))
+            == "CA:FALSE"
         )
 
     def test_type(self):
@@ -616,30 +628,40 @@ class TestX509Ext(object):
         """
         assert is_consistent_type(
             X509Extension,
-            'X509Extension', b'basicConstraints', True, b'CA:true')
+            "X509Extension",
+            b"basicConstraints",
+            True,
+            b"CA:true",
+        )
 
     def test_construction(self):
         """
         `X509Extension` accepts an extension type name, a critical flag,
         and an extension value and returns an `X509Extension` instance.
         """
-        basic = X509Extension(b'basicConstraints', True, b'CA:true')
+        basic = X509Extension(b"basicConstraints", True, b"CA:true")
         assert isinstance(basic, X509Extension)
 
-        comment = X509Extension(b'nsComment', False, b'pyOpenSSL unit test')
+        comment = X509Extension(b"nsComment", False, b"pyOpenSSL unit test")
         assert isinstance(comment, X509Extension)
 
-    @pytest.mark.parametrize('type_name, critical, value', [
-        (b'thisIsMadeUp', False, b'hi'),
-        (b'basicConstraints', False, b'blah blah'),
-
-        # Exercise a weird one (an extension which uses the r2i method).  This
-        # exercises the codepath that requires a non-NULL ctx to be passed to
-        # X509V3_EXT_nconf.  It can't work now because we provide no
-        # configuration database.  It might be made to work in the future.
-        (b'proxyCertInfo', True,
-         b'language:id-ppl-anyLanguage,pathlen:1,policy:text:AB')
-    ])
+    @pytest.mark.parametrize(
+        "type_name, critical, value",
+        [
+            (b"thisIsMadeUp", False, b"hi"),
+            (b"basicConstraints", False, b"blah blah"),
+            # Exercise a weird one (an extension which uses the r2i method).
+            # This exercises the codepath that requires a non-NULL ctx to be
+            # passed to X509V3_EXT_nconf. It can't work now because we provide
+            # no configuration database. It might be made to work in the
+            # future.
+            (
+                b"proxyCertInfo",
+                True,
+                b"language:id-ppl-anyLanguage,pathlen:1,policy:text:AB",
+            ),
+        ],
+    )
     def test_invalid_extension(self, type_name, critical, value):
         """
         `X509Extension` raises something if it is passed a bad
@@ -648,19 +670,19 @@ class TestX509Ext(object):
         with pytest.raises(Error):
             X509Extension(type_name, critical, value)
 
-    @pytest.mark.parametrize('critical_flag', [True, False])
+    @pytest.mark.parametrize("critical_flag", [True, False])
     def test_get_critical(self, critical_flag):
         """
         `X509ExtensionType.get_critical` returns the value of the
         extension's critical flag.
         """
-        ext = X509Extension(b'basicConstraints', critical_flag, b'CA:true')
+        ext = X509Extension(b"basicConstraints", critical_flag, b"CA:true")
         assert ext.get_critical() == critical_flag
 
-    @pytest.mark.parametrize('short_name, value', [
-        (b'basicConstraints', b'CA:true'),
-        (b'nsComment', b'foo bar'),
-    ])
+    @pytest.mark.parametrize(
+        "short_name, value",
+        [(b"basicConstraints", b"CA:true"), (b"nsComment", b"foo bar")],
+    )
     def test_get_short_name(self, short_name, value):
         """
         `X509ExtensionType.get_short_name` returns a string giving the
@@ -674,9 +696,9 @@ class TestX509Ext(object):
         `X509Extension.get_data` returns a string giving the data of
         the extension.
         """
-        ext = X509Extension(b'basicConstraints', True, b'CA:true')
+        ext = X509Extension(b"basicConstraints", True, b"CA:true")
         # Expect to get back the DER encoded form of CA:true.
-        assert ext.get_data() == b'0\x03\x01\x01\xff'
+        assert ext.get_data() == b"0\x03\x01\x01\xff"
 
     def test_unused_subject(self, x509_data):
         """
@@ -685,13 +707,14 @@ class TestX509Ext(object):
         """
         pkey, x509 = x509_data
         ext1 = X509Extension(
-            b'basicConstraints', False, b'CA:TRUE', subject=x509)
+            b"basicConstraints", False, b"CA:TRUE", subject=x509
+        )
         x509.add_extensions([ext1])
-        x509.sign(pkey, 'sha1')
+        x509.sign(pkey, "sha1")
         # This is a little lame.  Can we think of a better way?
         text = dump_certificate(FILETYPE_TEXT, x509)
-        assert b'X509v3 Basic Constraints:' in text
-        assert b'CA:TRUE' in text
+        assert b"X509v3 Basic Constraints:" in text
+        assert b"CA:TRUE" in text
 
     def test_subject(self, x509_data):
         """
@@ -700,11 +723,12 @@ class TestX509Ext(object):
         """
         pkey, x509 = x509_data
         ext3 = X509Extension(
-            b'subjectKeyIdentifier', False, b'hash', subject=x509)
+            b"subjectKeyIdentifier", False, b"hash", subject=x509
+        )
         x509.add_extensions([ext3])
-        x509.sign(pkey, 'sha1')
+        x509.sign(pkey, "sha1")
         text = dump_certificate(FILETYPE_TEXT, x509)
-        assert b'X509v3 Subject Key Identifier:' in text
+        assert b"X509v3 Subject Key Identifier:" in text
 
     def test_missing_subject(self):
         """
@@ -712,14 +736,9 @@ class TestX509Ext(object):
         is given no value, something happens.
         """
         with pytest.raises(Error):
-            X509Extension(b'subjectKeyIdentifier', False, b'hash')
-
-    @pytest.mark.parametrize('bad_obj', [
-        True,
-        object(),
-        "hello",
-        [],
-    ])
+            X509Extension(b"subjectKeyIdentifier", False, b"hash")
+
+    @pytest.mark.parametrize("bad_obj", [True, object(), "hello", []])
     def test_invalid_subject(self, bad_obj):
         """
         If the `subject` parameter is given a value which is not an
@@ -727,7 +746,8 @@ class TestX509Ext(object):
         """
         with pytest.raises(TypeError):
             X509Extension(
-                'basicConstraints', False, 'CA:TRUE', subject=bad_obj)
+                "basicConstraints", False, "CA:TRUE", subject=bad_obj
+            )
 
     def test_unused_issuer(self, x509_data):
         """
@@ -736,12 +756,13 @@ class TestX509Ext(object):
         """
         pkey, x509 = x509_data
         ext1 = X509Extension(
-            b'basicConstraints', False, b'CA:TRUE', issuer=x509)
+            b"basicConstraints", False, b"CA:TRUE", issuer=x509
+        )
         x509.add_extensions([ext1])
-        x509.sign(pkey, 'sha1')
+        x509.sign(pkey, "sha1")
         text = dump_certificate(FILETYPE_TEXT, x509)
-        assert b'X509v3 Basic Constraints:' in text
-        assert b'CA:TRUE' in text
+        assert b"X509v3 Basic Constraints:" in text
+        assert b"CA:TRUE" in text
 
     def test_issuer(self, x509_data):
         """
@@ -750,13 +771,13 @@ class TestX509Ext(object):
         """
         pkey, x509 = x509_data
         ext2 = X509Extension(
-            b'authorityKeyIdentifier', False, b'issuer:always',
-            issuer=x509)
+            b"authorityKeyIdentifier", False, b"issuer:always", issuer=x509
+        )
         x509.add_extensions([ext2])
-        x509.sign(pkey, 'sha1')
+        x509.sign(pkey, "sha1")
         text = dump_certificate(FILETYPE_TEXT, x509)
-        assert b'X509v3 Authority Key Identifier:' in text
-        assert b'DirName:/CN=Yoda root CA' in text
+        assert b"X509v3 Authority Key Identifier:" in text
+        assert b"DirName:/CN=Yoda root CA" in text
 
     def test_missing_issuer(self):
         """
@@ -765,15 +786,10 @@ class TestX509Ext(object):
         """
         with pytest.raises(Error):
             X509Extension(
-                b'authorityKeyIdentifier',
-                False, b'keyid:always,issuer:always')
-
-    @pytest.mark.parametrize('bad_obj', [
-        True,
-        object(),
-        "hello",
-        [],
-    ])
+                b"authorityKeyIdentifier", False, b"keyid:always,issuer:always"
+            )
+
+    @pytest.mark.parametrize("bad_obj", [True, object(), "hello", []])
     def test_invalid_issuer(self, bad_obj):
         """
         If the `issuer` parameter is given a value which is not an
@@ -781,8 +797,11 @@ class TestX509Ext(object):
         """
         with pytest.raises(TypeError):
             X509Extension(
-                'basicConstraints', False, 'keyid:always,issuer:always',
-                issuer=bad_obj)
+                "basicConstraints",
+                False,
+                "keyid:always,issuer:always",
+                issuer=bad_obj,
+            )
 
 
 class TestPKey(object):
@@ -850,7 +869,7 @@ class TestPKey(object):
         """
         `PKey` can be used to create instances of that type.
         """
-        assert is_consistent_type(PKey, 'PKey')
+        assert is_consistent_type(PKey, "PKey")
 
     def test_construction(self):
         """
@@ -992,6 +1011,7 @@ def x509_name(**attrs):
     # Make the order stable - order matters!
     def key(attr):
         return attr[1]
+
     attrs.sort(key=key)
     for k, v in attrs:
         setattr(name, k, v)
@@ -1099,6 +1119,7 @@ class TestX509Name(object):
         """
         `X509Name` instances should compare based on their NIDs.
         """
+
         def _equality(a, b, assert_true, assert_false):
             assert_true(a == b)
             assert_false(a != b)
@@ -1122,30 +1143,28 @@ class TestX509Name(object):
         assert_equal(x509_name(), x509_name())
 
         # Instances with equal NIDs should compare equal to each other.
-        assert_equal(x509_name(commonName="foo"),
-                     x509_name(commonName="foo"))
+        assert_equal(x509_name(commonName="foo"), x509_name(commonName="foo"))
 
         # Instance with equal NIDs set using different aliases should compare
         # equal to each other.
-        assert_equal(x509_name(commonName="foo"),
-                     x509_name(CN="foo"))
+        assert_equal(x509_name(commonName="foo"), x509_name(CN="foo"))
 
         # Instances with more than one NID with the same values should compare
         # equal to each other.
-        assert_equal(x509_name(CN="foo", organizationalUnitName="bar"),
-                     x509_name(commonName="foo", OU="bar"))
+        assert_equal(
+            x509_name(CN="foo", organizationalUnitName="bar"),
+            x509_name(commonName="foo", OU="bar"),
+        )
 
         def assert_not_equal(a, b):
             _equality(a, b, assert_false, assert_true)
 
         # Instances with different values for the same NID should not compare
         # equal to each other.
-        assert_not_equal(x509_name(CN="foo"),
-                         x509_name(CN="bar"))
+        assert_not_equal(x509_name(CN="foo"), x509_name(CN="bar"))
 
         # Instances with different NIDs should not compare equal to each other.
-        assert_not_equal(x509_name(CN="foo"),
-                         x509_name(OU="foo"))
+        assert_not_equal(x509_name(CN="foo"), x509_name(OU="foo"))
 
         assert_not_equal(x509_name(), object())
 
@@ -1165,8 +1184,7 @@ class TestX509Name(object):
         # An X509Name with a NID with a value which sorts less than the value
         # of the same NID on another X509Name compares less than the other
         # X509Name.
-        assert_less_than(x509_name(CN="abc"),
-                         x509_name(CN="def"))
+        assert_less_than(x509_name(CN="abc"), x509_name(CN="def"))
 
         def assert_greater_than(a, b):
             _inequality(a, b, assert_false, assert_true)
@@ -1174,8 +1192,7 @@ class TestX509Name(object):
         # An X509Name with a NID with a value which sorts greater than the
         # value of the same NID on another X509Name compares greater than the
         # other X509Name.
-        assert_greater_than(x509_name(CN="def"),
-                            x509_name(CN="abc"))
+        assert_greater_than(x509_name(CN="def"), x509_name(CN="abc"))
 
     def test_hash(self):
         """
@@ -1192,9 +1209,10 @@ class TestX509Name(object):
         `X509Name.der` returns the DER encoded form of the name.
         """
         a = x509_name(CN="foo", C="US")
-        assert (a.der() ==
-                b'0\x1b1\x0b0\t\x06\x03U\x04\x06\x13\x02US'
-                b'1\x0c0\n\x06\x03U\x04\x03\x0c\x03foo')
+        assert (
+            a.der() == b"0\x1b1\x0b0\t\x06\x03U\x04\x06\x13\x02US"
+            b"1\x0c0\n\x06\x03U\x04\x03\x0c\x03foo"
+        )
 
     def test_get_components(self):
         """
@@ -1225,8 +1243,8 @@ class TestX509Name(object):
         cert = load_certificate(FILETYPE_PEM, nulbyteSubjectAltNamePEM)
         subject = cert.get_subject()
         components = subject.get_components()
-        ccn = [value for name, value in components if name == b'CN']
-        assert ccn[0] == b'null.python.org\x00example.org'
+        ccn = [value for name, value in components if name == b"CN"]
+        assert ccn[0] == b"null.python.org\x00example.org"
 
     def test_set_attribute_failure(self):
         """
@@ -1295,7 +1313,7 @@ class _PKeyInteractionTestsMixin:
         request.set_pubkey(key)
         request.sign(key, GOOD_DIGEST)
         # If the type has a verify method, cover that too.
-        if getattr(request, 'verify', None) is not None:
+        if getattr(request, "verify", None) is not None:
             pub = request.get_pubkey()
             assert request.verify(pub)
             # Make another key that won't verify.
@@ -1320,7 +1338,7 @@ class TestX509Req(_PKeyInteractionTestsMixin):
         """
         `X509Req` can be used to create instances of that type.
         """
-        assert is_consistent_type(X509Req, 'X509Req')
+        assert is_consistent_type(X509Req, "X509Req")
 
     def test_construction(self):
         """
@@ -1372,13 +1390,14 @@ class TestX509Req(_PKeyInteractionTestsMixin):
         and adds them to the X509 request.
         """
         request = X509Req()
-        request.add_extensions([
-            X509Extension(b'basicConstraints', True, b'CA:false')])
+        request.add_extensions(
+            [X509Extension(b"basicConstraints", True, b"CA:false")]
+        )
         exts = request.get_extensions()
         assert len(exts) == 1
-        assert exts[0].get_short_name() == b'basicConstraints'
+        assert exts[0].get_short_name() == b"basicConstraints"
         assert exts[0].get_critical() == 1
-        assert exts[0].get_data() == b'0\x00'
+        assert exts[0].get_data() == b"0\x00"
 
     def test_get_extensions(self):
         """
@@ -1388,17 +1407,20 @@ class TestX509Req(_PKeyInteractionTestsMixin):
         request = X509Req()
         exts = request.get_extensions()
         assert exts == []
-        request.add_extensions([
-            X509Extension(b'basicConstraints', True, b'CA:true'),
-            X509Extension(b'keyUsage', False, b'digitalSignature')])
+        request.add_extensions(
+            [
+                X509Extension(b"basicConstraints", True, b"CA:true"),
+                X509Extension(b"keyUsage", False, b"digitalSignature"),
+            ]
+        )
         exts = request.get_extensions()
         assert len(exts) == 2
-        assert exts[0].get_short_name() == b'basicConstraints'
+        assert exts[0].get_short_name() == b"basicConstraints"
         assert exts[0].get_critical() == 1
-        assert exts[0].get_data() == b'0\x03\x01\x01\xff'
-        assert exts[1].get_short_name() == b'keyUsage'
+        assert exts[0].get_data() == b"0\x03\x01\x01\xff"
+        assert exts[1].get_short_name() == b"keyUsage"
         assert exts[1].get_critical() == 0
-        assert exts[1].get_data() == b'\x03\x02\x07\x80'
+        assert exts[1].get_data() == b"\x03\x02\x07\x80"
 
     def test_add_extensions_wrong_args(self):
         """
@@ -1477,6 +1499,7 @@ class TestX509(_PKeyInteractionTestsMixin):
     """
     Tests for `OpenSSL.crypto.X509`.
     """
+
     pemData = cleartextCertificatePEM + cleartextPrivateKeyPEM
 
     extpem = """
@@ -1510,7 +1533,7 @@ WpOdIpB8KksUTCzV591Nr1wd
         """
         `X509` can be used to create instances of that type.
         """
-        assert is_consistent_type(X509, 'X509')
+        assert is_consistent_type(X509, "X509")
 
     def test_construction(self):
         """
@@ -1518,7 +1541,7 @@ WpOdIpB8KksUTCzV591Nr1wd
         """
         certificate = X509()
         assert isinstance(certificate, X509)
-        assert type(certificate).__name__ == 'X509'
+        assert type(certificate).__name__ == "X509"
         assert type(certificate) == X509
 
     def test_set_version_wrong_args(self):
@@ -1565,8 +1588,8 @@ WpOdIpB8KksUTCzV591Nr1wd
         validity period to it.
         """
         certificate = X509()
-        set = getattr(certificate, 'set_not' + which)
-        get = getattr(certificate, 'get_not' + which)
+        set = getattr(certificate, "set_not" + which)
+        get = getattr(certificate, "get_not" + which)
 
         # Starts with no value.
         assert get() is None
@@ -1650,8 +1673,8 @@ WpOdIpB8KksUTCzV591Nr1wd
         current time plus the number of seconds passed in.
         """
         cert = load_certificate(FILETYPE_PEM, self.pemData)
-        not_before_min = (
-            datetime.utcnow().replace(microsecond=0) + timedelta(seconds=100)
+        not_before_min = datetime.utcnow().replace(microsecond=0) + timedelta(
+            seconds=100
         )
         cert.gmtime_adj_notBefore(100)
         not_before = datetime.strptime(
@@ -1676,8 +1699,8 @@ WpOdIpB8KksUTCzV591Nr1wd
         to be the current time plus the number of seconds passed in.
         """
         cert = load_certificate(FILETYPE_PEM, self.pemData)
-        not_after_min = (
-            datetime.utcnow().replace(microsecond=0) + timedelta(seconds=100)
+        not_after_min = datetime.utcnow().replace(microsecond=0) + timedelta(
+            seconds=100
         )
         cert.gmtime_adj_notAfter(100)
         not_after = datetime.strptime(
@@ -1724,8 +1747,9 @@ WpOdIpB8KksUTCzV591Nr1wd
             # digest will not product the same digest).
             # Digest verified with the command:
             # openssl x509 -in root_cert.pem -noout -fingerprint -md5
-            cert.digest("MD5") ==
-            b"19:B3:05:26:2B:F8:F2:FF:0B:8F:21:07:A8:28:B8:75")
+            cert.digest("MD5")
+            == b"19:B3:05:26:2B:F8:F2:FF:0B:8F:21:07:A8:28:B8:75"
+        )
 
     def _extcert(self, pkey, extensions):
         cert = X509()
@@ -1740,9 +1764,10 @@ WpOdIpB8KksUTCzV591Nr1wd
         cert.set_notAfter(when)
 
         cert.add_extensions(extensions)
-        cert.sign(pkey, 'sha1')
+        cert.sign(pkey, "sha1")
         return load_certificate(
-            FILETYPE_PEM, dump_certificate(FILETYPE_PEM, cert))
+            FILETYPE_PEM, dump_certificate(FILETYPE_PEM, cert)
+        )
 
     def test_extension_count(self):
         """
@@ -1750,10 +1775,11 @@ WpOdIpB8KksUTCzV591Nr1wd
         that are present in the certificate.
         """
         pkey = load_privatekey(FILETYPE_PEM, client_key_pem)
-        ca = X509Extension(b'basicConstraints', True, b'CA:FALSE')
-        key = X509Extension(b'keyUsage', True, b'digitalSignature')
+        ca = X509Extension(b"basicConstraints", True, b"CA:FALSE")
+        key = X509Extension(b"keyUsage", True, b"digitalSignature")
         subjectAltName = X509Extension(
-            b'subjectAltName', True, b'DNS:example.com')
+            b"subjectAltName", True, b"DNS:example.com"
+        )
 
         # Try a certificate with no extensions at all.
         c = self._extcert(pkey, [])
@@ -1773,27 +1799,28 @@ WpOdIpB8KksUTCzV591Nr1wd
         `X509Extension` corresponding to the extension at that index.
         """
         pkey = load_privatekey(FILETYPE_PEM, client_key_pem)
-        ca = X509Extension(b'basicConstraints', True, b'CA:FALSE')
-        key = X509Extension(b'keyUsage', True, b'digitalSignature')
+        ca = X509Extension(b"basicConstraints", True, b"CA:FALSE")
+        key = X509Extension(b"keyUsage", True, b"digitalSignature")
         subjectAltName = X509Extension(
-            b'subjectAltName', False, b'DNS:example.com')
+            b"subjectAltName", False, b"DNS:example.com"
+        )
 
         cert = self._extcert(pkey, [ca, key, subjectAltName])
 
         ext = cert.get_extension(0)
         assert isinstance(ext, X509Extension)
         assert ext.get_critical()
-        assert ext.get_short_name() == b'basicConstraints'
+        assert ext.get_short_name() == b"basicConstraints"
 
         ext = cert.get_extension(1)
         assert isinstance(ext, X509Extension)
         assert ext.get_critical()
-        assert ext.get_short_name() == b'keyUsage'
+        assert ext.get_short_name() == b"keyUsage"
 
         ext = cert.get_extension(2)
         assert isinstance(ext, X509Extension)
         assert not ext.get_critical()
-        assert ext.get_short_name() == b'subjectAltName'
+        assert ext.get_short_name() == b"subjectAltName"
 
         with pytest.raises(IndexError):
             cert.get_extension(-1)
@@ -1811,13 +1838,14 @@ WpOdIpB8KksUTCzV591Nr1wd
         cert = load_certificate(FILETYPE_PEM, nulbyteSubjectAltNamePEM)
 
         ext = cert.get_extension(3)
-        assert ext.get_short_name() == b'subjectAltName'
+        assert ext.get_short_name() == b"subjectAltName"
         assert (
             b"DNS:altnull.python.org\x00example.com, "
             b"email:null@python.org\x00user@example.org, "
             b"URI:http://null.python.org\x00http://example.org, "
-            b"IP Address:192.0.2.1, IP Address:2001:DB8:0:0:0:0:0:1\n" ==
-            str(ext).encode("ascii"))
+            b"IP Address:192.0.2.1, IP Address:2001:DB8:0:0:0:0:0:1\n"
+            == str(ext).encode("ascii")
+        )
 
     def test_invalid_digest_algorithm(self):
         """
@@ -1835,10 +1863,13 @@ WpOdIpB8KksUTCzV591Nr1wd
         cert = load_certificate(FILETYPE_PEM, self.pemData)
         subj = cert.get_subject()
         assert isinstance(subj, X509Name)
-        assert (
-            subj.get_components() ==
-            [(b'C', b'US'), (b'ST', b'IL'), (b'L', b'Chicago'),
-             (b'O', b'Testing'), (b'CN', b'Testing Root CA')])
+        assert subj.get_components() == [
+            (b"C", b"US"),
+            (b"ST", b"IL"),
+            (b"L", b"Chicago"),
+            (b"O", b"Testing"),
+            (b"CN", b"Testing Root CA"),
+        ]
 
     def test_set_subject_wrong_args(self):
         """
@@ -1856,12 +1887,13 @@ WpOdIpB8KksUTCzV591Nr1wd
         """
         cert = X509()
         name = cert.get_subject()
-        name.C = 'AU'
-        name.OU = 'Unit Tests'
+        name.C = "AU"
+        name.OU = "Unit Tests"
         cert.set_subject(name)
-        assert (
-            cert.get_subject().get_components() ==
-            [(b'C', b'AU'), (b'OU', b'Unit Tests')])
+        assert cert.get_subject().get_components() == [
+            (b"C", b"AU"),
+            (b"OU", b"Unit Tests"),
+        ]
 
     def test_get_issuer(self):
         """
@@ -1871,10 +1903,13 @@ WpOdIpB8KksUTCzV591Nr1wd
         subj = cert.get_issuer()
         assert isinstance(subj, X509Name)
         comp = subj.get_components()
-        assert (
-            comp ==
-            [(b'C', b'US'), (b'ST', b'IL'), (b'L', b'Chicago'),
-             (b'O', b'Testing'), (b'CN', b'Testing Root CA')])
+        assert comp == [
+            (b"C", b"US"),
+            (b"ST", b"IL"),
+            (b"L", b"Chicago"),
+            (b"O", b"Testing"),
+            (b"CN", b"Testing Root CA"),
+        ]
 
     def test_set_issuer_wrong_args(self):
         """
@@ -1892,12 +1927,13 @@ WpOdIpB8KksUTCzV591Nr1wd
         """
         cert = X509()
         name = cert.get_issuer()
-        name.C = 'AU'
-        name.OU = 'Unit Tests'
+        name.C = "AU"
+        name.OU = "Unit Tests"
         cert.set_issuer(name)
-        assert (
-            cert.get_issuer().get_components() ==
-            [(b'C', b'AU'), (b'OU', b'Unit Tests')])
+        assert cert.get_issuer().get_components() == [
+            (b"C", b"AU"),
+            (b"OU", b"Unit Tests"),
+        ]
 
     def test_get_pubkey_uninitialized(self):
         """
@@ -2004,7 +2040,7 @@ class TestX509Store(object):
         """
         `X509Store` is a type object.
         """
-        assert is_consistent_type(X509Store, 'X509Store')
+        assert is_consistent_type(X509Store, "X509Store")
 
     def test_add_cert(self):
         """
@@ -2014,7 +2050,7 @@ class TestX509Store(object):
         store = X509Store()
         store.add_cert(cert)
 
-    @pytest.mark.parametrize('cert', [None, 1.0, 'cert', object()])
+    @pytest.mark.parametrize("cert", [None, 1.0, "cert", object()])
     def test_add_cert_wrong_args(self, cert):
         """
         `X509Store.add_cert` raises `TypeError` if passed a non-X509 object
@@ -2039,13 +2075,14 @@ class TestPKCS12(object):
     """
     Test for `OpenSSL.crypto.PKCS12` and `OpenSSL.crypto.load_pkcs12`.
     """
+
     pemData = cleartextCertificatePEM + cleartextPrivateKeyPEM
 
     def test_type(self):
         """
         `PKCS12` is a type object.
         """
-        assert is_consistent_type(PKCS12, 'PKCS12')
+        assert is_consistent_type(PKCS12, "PKCS12")
 
     def test_empty_construction(self):
         """
@@ -2068,13 +2105,13 @@ class TestPKCS12(object):
         for bad_arg in [3, PKey(), X509]:
             with pytest.raises(TypeError):
                 p12.set_certificate(bad_arg)
-        for bad_arg in [3, 'legbone', X509()]:
+        for bad_arg in [3, "legbone", X509()]:
             with pytest.raises(TypeError):
                 p12.set_privatekey(bad_arg)
         for bad_arg in [3, X509(), (3, 4), (PKey(),)]:
             with pytest.raises(TypeError):
                 p12.set_ca_certificates(bad_arg)
-        for bad_arg in [6, ('foo', 'bar')]:
+        for bad_arg in [6, ("foo", "bar")]:
             with pytest.raises(TypeError):
                 p12.set_friendlyname(bad_arg)
 
@@ -2134,12 +2171,13 @@ class TestPKCS12(object):
         # it to.  At some point, hopefully this will change so that
         # p12.get_certificate() is actually what returns the loaded
         # certificate.
-        assert (
-            cleartextCertificatePEM ==
-            dump_certificate(FILETYPE_PEM, p12.get_ca_certificates()[0]))
+        assert cleartextCertificatePEM == dump_certificate(
+            FILETYPE_PEM, p12.get_ca_certificates()[0]
+        )
 
-    def gen_pkcs12(self, cert_pem=None, key_pem=None, ca_pem=None,
-                   friendly_name=None):
+    def gen_pkcs12(
+        self, cert_pem=None, key_pem=None, ca_pem=None, friendly_name=None
+    ):
         """
         Generate a PKCS12 object with components from PEM.  Verify that the set
         functions return None.
@@ -2161,27 +2199,48 @@ class TestPKCS12(object):
             assert ret is None
         return p12
 
-    def check_recovery(self, p12_str, key=None, cert=None, ca=None, passwd=b"",
-                       extra=()):
+    def check_recovery(
+        self, p12_str, key=None, cert=None, ca=None, passwd=b"", extra=()
+    ):
         """
         Use openssl program to confirm three components are recoverable from a
         PKCS12 string.
         """
         if key:
             recovered_key = _runopenssl(
-                p12_str, b"pkcs12", b"-nocerts", b"-nodes", b"-passin",
-                b"pass:" + passwd, *extra)
-            assert recovered_key[-len(key):] == key
+                p12_str,
+                b"pkcs12",
+                b"-nocerts",
+                b"-nodes",
+                b"-passin",
+                b"pass:" + passwd,
+                *extra
+            )
+            assert recovered_key[-len(key) :] == key
         if cert:
             recovered_cert = _runopenssl(
-                p12_str, b"pkcs12", b"-clcerts", b"-nodes", b"-passin",
-                b"pass:" + passwd, b"-nokeys", *extra)
-            assert recovered_cert[-len(cert):] == cert
+                p12_str,
+                b"pkcs12",
+                b"-clcerts",
+                b"-nodes",
+                b"-passin",
+                b"pass:" + passwd,
+                b"-nokeys",
+                *extra
+            )
+            assert recovered_cert[-len(cert) :] == cert
         if ca:
             recovered_cert = _runopenssl(
-                p12_str, b"pkcs12", b"-cacerts", b"-nodes", b"-passin",
-                b"pass:" + passwd, b"-nokeys", *extra)
-            assert recovered_cert[-len(ca):] == ca
+                p12_str,
+                b"pkcs12",
+                b"-cacerts",
+                b"-nodes",
+                b"-passin",
+                b"pass:" + passwd,
+                b"-nokeys",
+                *extra
+            )
+            assert recovered_cert[-len(ca) :] == ca
 
     def verify_pkcs12_container(self, p12):
         """
@@ -2193,9 +2252,11 @@ class TestPKCS12(object):
         """
         cert_pem = dump_certificate(FILETYPE_PEM, p12.get_certificate())
         key_pem = dump_privatekey(FILETYPE_PEM, p12.get_privatekey())
-        assert (
-            (client_cert_pem, client_key_pem, None) ==
-            (cert_pem, key_pem, p12.get_ca_certificates()))
+        assert (client_cert_pem, client_key_pem, None) == (
+            cert_pem,
+            key_pem,
+            p12.get_ca_certificates(),
+        )
 
     def test_load_pkcs12(self):
         """
@@ -2210,7 +2271,7 @@ class TestPKCS12(object):
             b"-export",
             b"-clcerts",
             b"-passout",
-            b"pass:" + passwd
+            b"pass:" + passwd,
         )
         p12 = load_pkcs12(p12_str, passphrase=passwd)
         self.verify_pkcs12_container(p12)
@@ -2223,15 +2284,21 @@ class TestPKCS12(object):
         """
         pem = client_key_pem + client_cert_pem
         passwd = b"whatever"
-        p12_str = _runopenssl(pem, b"pkcs12", b"-export", b"-clcerts",
-                              b"-passout", b"pass:" + passwd)
+        p12_str = _runopenssl(
+            pem,
+            b"pkcs12",
+            b"-export",
+            b"-clcerts",
+            b"-passout",
+            b"pass:" + passwd,
+        )
         with pytest.warns(DeprecationWarning) as w:
             simplefilter("always")
             p12 = load_pkcs12(p12_str, passphrase=b"whatever".decode("ascii"))
-            assert (
-                "{0} for passphrase is no longer accepted, use bytes".format(
-                    WARNING_TYPE_EXPECTED
-                ) == str(w[-1].message))
+            msg = "{0} for passphrase is no longer accepted, use bytes".format(
+                WARNING_TYPE_EXPECTED
+            )
+            assert msg == str(w[-1].message)
 
         self.verify_pkcs12_container(p12)
 
@@ -2243,7 +2310,8 @@ class TestPKCS12(object):
         """
         pem = client_key_pem + client_cert_pem
         p12_str = _runopenssl(
-            pem, b"pkcs12", b"-export", b"-clcerts", b"-passout", b"pass:")
+            pem, b"pkcs12", b"-export", b"-clcerts", b"-passout", b"pass:"
+        )
         p12 = load_pkcs12(p12_str)
         self.verify_pkcs12_container(p12)
 
@@ -2262,7 +2330,8 @@ class TestPKCS12(object):
         extracted and examined.
         """
         self.verify_pkcs12_container(
-            self._dump_and_load(dump_passphrase=None, load_passphrase=b''))
+            self._dump_and_load(dump_passphrase=None, load_passphrase=b"")
+        )
 
     def test_load_pkcs12_null_passphrase_load_null(self):
         """
@@ -2271,7 +2340,8 @@ class TestPKCS12(object):
         extracted and examined.
         """
         self.verify_pkcs12_container(
-            self._dump_and_load(dump_passphrase=None, load_passphrase=None))
+            self._dump_and_load(dump_passphrase=None, load_passphrase=None)
+        )
 
     def test_load_pkcs12_empty_passphrase_load_empty(self):
         """
@@ -2280,7 +2350,8 @@ class TestPKCS12(object):
         extracted and examined.
         """
         self.verify_pkcs12_container(
-            self._dump_and_load(dump_passphrase=b'', load_passphrase=b''))
+            self._dump_and_load(dump_passphrase=b"", load_passphrase=b"")
+        )
 
     def test_load_pkcs12_empty_passphrase_load_null(self):
         """
@@ -2289,17 +2360,18 @@ class TestPKCS12(object):
         extracted and examined.
         """
         self.verify_pkcs12_container(
-            self._dump_and_load(dump_passphrase=b'', load_passphrase=None))
+            self._dump_and_load(dump_passphrase=b"", load_passphrase=None)
+        )
 
     def test_load_pkcs12_garbage(self):
         """
         `load_pkcs12` raises `OpenSSL.crypto.Error` when passed
         a string which is not a PKCS12 dump.
         """
-        passwd = 'whatever'
+        passwd = "whatever"
         with pytest.raises(Error) as err:
-            load_pkcs12(b'fruit loops', passwd)
-        assert err.value.args[0][0][0] == 'asn1 encoding routines'
+            load_pkcs12(b"fruit loops", passwd)
+        assert err.value.args[0][0][0] == "asn1 encoding routines"
         assert len(err.value.args[0][0]) == 3
 
     def test_replace(self):
@@ -2329,7 +2401,7 @@ class TestPKCS12(object):
         """
         passwd = b'Dogmeat[]{}!@#$%^&*()~`?/.,<>-_+=";:'
         p12 = self.gen_pkcs12(server_cert_pem, server_key_pem, root_cert_pem)
-        for friendly_name in [b'Serverlicious', None, b'###']:
+        for friendly_name in [b"Serverlicious", None, b"###"]:
             p12.set_friendlyname(friendly_name)
             assert p12.get_friendlyname() == friendly_name
             dumped_p12 = p12.export(passphrase=passwd, iter=2, maciter=3)
@@ -2340,8 +2412,12 @@ class TestPKCS12(object):
             # does not store the friendly name in the cert's
             # alias, which we could then extract.
             self.check_recovery(
-                dumped_p12, key=server_key_pem, cert=server_cert_pem,
-                ca=root_cert_pem, passwd=passwd)
+                dumped_p12,
+                key=server_key_pem,
+                cert=server_cert_pem,
+                ca=root_cert_pem,
+                passwd=passwd,
+            )
 
     def test_various_empty_passphrases(self):
         """
@@ -2355,8 +2431,12 @@ class TestPKCS12(object):
         dumped_p12_nopw = p12.export(iter=9, maciter=4)
         for dumped_p12 in [dumped_p12_empty, dumped_p12_none, dumped_p12_nopw]:
             self.check_recovery(
-                dumped_p12, key=client_key_pem, cert=client_cert_pem,
-                ca=root_cert_pem, passwd=passwd)
+                dumped_p12,
+                key=client_key_pem,
+                cert=client_cert_pem,
+                ca=root_cert_pem,
+                passwd=passwd,
+            )
 
     def test_removing_ca_cert(self):
         """
@@ -2375,8 +2455,12 @@ class TestPKCS12(object):
         p12 = self.gen_pkcs12(server_cert_pem, server_key_pem, root_cert_pem)
         dumped_p12 = p12.export(maciter=-1, passphrase=passwd, iter=2)
         self.check_recovery(
-            dumped_p12, key=server_key_pem, cert=server_cert_pem,
-            passwd=passwd, extra=(b"-nomacver",))
+            dumped_p12,
+            key=server_key_pem,
+            cert=server_cert_pem,
+            passwd=passwd,
+            extra=(b"-nomacver",),
+        )
 
     def test_load_without_mac(self):
         """
@@ -2402,14 +2486,14 @@ class TestPKCS12(object):
         """
         A PKCS12 with an empty CA certificates list can be exported.
         """
-        passwd = b'Hobie 18'
+        passwd = b"Hobie 18"
         p12 = self.gen_pkcs12(server_cert_pem, server_key_pem)
         p12.set_ca_certificates([])
         assert () == p12.get_ca_certificates()
         dumped_p12 = p12.export(passphrase=passwd, iter=3)
         self.check_recovery(
-            dumped_p12, key=server_key_pem, cert=server_cert_pem,
-            passwd=passwd)
+            dumped_p12, key=server_key_pem, cert=server_cert_pem, passwd=passwd
+        )
 
     def test_export_without_args(self):
         """
@@ -2418,7 +2502,8 @@ class TestPKCS12(object):
         p12 = self.gen_pkcs12(server_cert_pem, server_key_pem, root_cert_pem)
         dumped_p12 = p12.export()  # no args
         self.check_recovery(
-            dumped_p12, key=server_key_pem, cert=server_cert_pem, passwd=b"")
+            dumped_p12, key=server_key_pem, cert=server_cert_pem, passwd=b""
+        )
 
     def test_export_without_bytes(self):
         """
@@ -2429,15 +2514,15 @@ class TestPKCS12(object):
         with pytest.warns(DeprecationWarning) as w:
             simplefilter("always")
             dumped_p12 = p12.export(passphrase=b"randomtext".decode("ascii"))
-            assert (
-                "{0} for passphrase is no longer accepted, use bytes".format(
-                    WARNING_TYPE_EXPECTED
-                ) == str(w[-1].message))
+            msg = "{0} for passphrase is no longer accepted, use bytes".format(
+                WARNING_TYPE_EXPECTED
+            )
+            assert msg == str(w[-1].message)
         self.check_recovery(
             dumped_p12,
             key=server_key_pem,
             cert=server_cert_pem,
-            passwd=b"randomtext"
+            passwd=b"randomtext",
         )
 
     def test_key_cert_mismatch(self):
@@ -2468,6 +2553,7 @@ class TestLoadPublicKey(object):
     """
     Tests for :func:`load_publickey`.
     """
+
     def test_loading_works(self):
         """
         load_publickey loads public keys and sets correct attributes.
@@ -2496,7 +2582,7 @@ class TestLoadPublicKey(object):
         """
         load_publickey works with text strings, not just bytes.
         """
-        serialized = cleartextPublicKeyPEM.decode('ascii')
+        serialized = cleartextPublicKeyPEM.decode("ascii")
         key = load_publickey(FILETYPE_PEM, serialized)
         dumped_pem = dump_publickey(FILETYPE_PEM, key)
 
@@ -2522,7 +2608,8 @@ class TestFunction(object):
         """
         with pytest.raises(TypeError):
             load_privatekey(
-                FILETYPE_PEM, encryptedPrivateKeyPEMPassphrase, object())
+                FILETYPE_PEM, encryptedPrivateKeyPEMPassphrase, object()
+            )
 
     def test_load_privatekey_wrongPassphrase(self):
         """
@@ -2550,8 +2637,10 @@ class TestFunction(object):
         string if given the passphrase.
         """
         key = load_privatekey(
-            FILETYPE_PEM, encryptedPrivateKeyPEM,
-            encryptedPrivateKeyPEMPassphrase)
+            FILETYPE_PEM,
+            encryptedPrivateKeyPEM,
+            encryptedPrivateKeyPEMPassphrase,
+        )
         assert isinstance(key, PKey)
 
     def test_load_privatekey_passphrase_exception(self):
@@ -2559,6 +2648,7 @@ class TestFunction(object):
         If the passphrase callback raises an exception, that exception is
         raised by `load_privatekey`.
         """
+
         def cb(ignored):
             raise ArithmeticError
 
@@ -2576,6 +2666,7 @@ class TestFunction(object):
         def cb(*a):
             called.append(None)
             return b"quack"
+
         with pytest.raises(Error) as err:
             load_privatekey(FILETYPE_PEM, encryptedPrivateKeyPEM, cb)
         assert called
@@ -2592,6 +2683,7 @@ class TestFunction(object):
         def cb(writing):
             called.append(writing)
             return encryptedPrivateKeyPEMPassphrase
+
         key = load_privatekey(FILETYPE_PEM, encryptedPrivateKeyPEM, cb)
         assert isinstance(key, PKey)
         assert called == [False]
@@ -2603,7 +2695,8 @@ class TestFunction(object):
         """
         with pytest.raises(ValueError):
             load_privatekey(
-                FILETYPE_PEM, encryptedPrivateKeyPEM, lambda *args: 3)
+                FILETYPE_PEM, encryptedPrivateKeyPEM, lambda *args: 3
+            )
 
     def test_dump_privatekey_wrong_args(self):
         """
@@ -2664,6 +2757,7 @@ class TestFunction(object):
         `crypto.load_privatekey` should raise an error when the passphrase
         provided by the callback is too long, not silently truncate it.
         """
+
         def cb(ignored):
             return "a" * 1025
 
@@ -2709,7 +2803,8 @@ class TestFunction(object):
         assert dumped_pem2 == cleartextCertificatePEM
         dumped_text = dump_certificate(FILETYPE_TEXT, cert)
         good_text = _runopenssl(
-            dumped_pem, b"x509", b"-noout", b"-text", b"-nameopt", b"")
+            dumped_pem, b"x509", b"-noout", b"-text", b"-nameopt", b""
+        )
         assert dumped_text == good_text
 
     def test_dump_certificate_bad_type(self):
@@ -2788,7 +2883,8 @@ class TestFunction(object):
         `dump_certificate_request` writes a PEM, DER, and text.
         """
         req = load_certificate_request(
-            FILETYPE_PEM, cleartextCertificateRequestPEM)
+            FILETYPE_PEM, cleartextCertificateRequestPEM
+        )
         dumped_pem = dump_certificate_request(FILETYPE_PEM, req)
         assert dumped_pem == cleartextCertificateRequestPEM
         dumped_der = dump_certificate_request(FILETYPE_ASN1, req)
@@ -2799,7 +2895,8 @@ class TestFunction(object):
         assert dumped_pem2 == cleartextCertificateRequestPEM
         dumped_text = dump_certificate_request(FILETYPE_TEXT, req)
         good_text = _runopenssl(
-            dumped_pem, b"req", b"-noout", b"-text", b"-nameopt", b"")
+            dumped_pem, b"req", b"-noout", b"-text", b"-nameopt", b""
+        )
         assert dumped_text == good_text
         with pytest.raises(ValueError):
             dump_certificate_request(100, req)
@@ -2815,6 +2912,7 @@ class TestFunction(object):
         def cb(writing):
             called.append(writing)
             return passphrase
+
         key = load_privatekey(FILETYPE_PEM, cleartextPrivateKeyPEM)
         pem = dump_privatekey(FILETYPE_PEM, key, GOOD_CIPHER, cb)
         assert isinstance(pem, bytes)
@@ -2829,6 +2927,7 @@ class TestFunction(object):
         `dump_privatekey` should not overwrite the exception raised
         by the passphrase callback.
         """
+
         def cb(ignored):
             raise ArithmeticError
 
@@ -2841,6 +2940,7 @@ class TestFunction(object):
         `crypto.dump_privatekey` should raise an error when the passphrase
         provided by the callback is too long, not silently truncate it.
         """
+
         def cb(ignored):
             return "a" * 1025
 
@@ -2946,7 +3046,7 @@ class TestPKCS7(object):
         type name.
         """
         pkcs7 = load_pkcs7_data(FILETYPE_PEM, pkcs7Data)
-        assert pkcs7.get_type_name() == b'pkcs7-signedData'
+        assert pkcs7.get_type_name() == b"pkcs7-signedData"
 
     def test_attribute(self):
         """
@@ -2973,7 +3073,7 @@ class TestNetscapeSPKI(_PKeyInteractionTestsMixin):
         """
         `NetscapeSPKI` can be used to create instances of that type.
         """
-        assert is_consistent_type(NetscapeSPKI, 'NetscapeSPKI')
+        assert is_consistent_type(NetscapeSPKI, "NetscapeSPKI")
 
     def test_construction(self):
         """
@@ -3004,6 +3104,7 @@ class TestRevoked(object):
     """
     Tests for `OpenSSL.crypto.Revoked`.
     """
+
     def test_ignores_unsupported_revoked_cert_extension_get_reason(self):
         """
         The get_reason method on the Revoked class checks to see if the
@@ -3013,7 +3114,7 @@ class TestRevoked(object):
         crl = load_crl(FILETYPE_PEM, crlDataUnsupportedExtension)
         revoked = crl.get_revoked()
         reason = revoked[1].get_reason()
-        assert reason == b'Unspecified'
+        assert reason == b"Unspecified"
 
     def test_ignores_unsupported_revoked_cert_extension_set_new_reason(self):
         crl = load_crl(FILETYPE_PEM, crlDataUnsupportedExtension)
@@ -3030,7 +3131,7 @@ class TestRevoked(object):
         revoked = Revoked()
         assert isinstance(revoked, Revoked)
         assert type(revoked) == Revoked
-        assert revoked.get_serial() == b'00'
+        assert revoked.get_serial() == b"00"
         assert revoked.get_rev_date() is None
         assert revoked.get_reason() is None
 
@@ -3040,17 +3141,17 @@ class TestRevoked(object):
         `OpenSSL.crypto.Revoked`.  Confirm errors are handled with grace.
         """
         revoked = Revoked()
-        ret = revoked.set_serial(b'10b')
+        ret = revoked.set_serial(b"10b")
         assert ret is None
         ser = revoked.get_serial()
-        assert ser == b'010B'
+        assert ser == b"010B"
 
-        revoked.set_serial(b'31ppp')  # a type error would be nice
+        revoked.set_serial(b"31ppp")  # a type error would be nice
         ser = revoked.get_serial()
-        assert ser == b'31'
+        assert ser == b"31"
 
         with pytest.raises(ValueError):
-            revoked.set_serial(b'pqrst')
+            revoked.set_serial(b"pqrst")
         with pytest.raises(TypeError):
             revoked.set_serial(100)
 
@@ -3081,15 +3182,15 @@ class TestRevoked(object):
                 ret = revoked.set_reason(r)
                 assert ret is None
                 reason = revoked.get_reason()
-                assert (
-                    reason.lower().replace(b' ', b'') ==
-                    r.lower().replace(b' ', b''))
+                assert reason.lower().replace(b" ", b"") == r.lower().replace(
+                    b" ", b""
+                )
                 r = reason  # again with the resp of get
 
         revoked.set_reason(None)
         assert revoked.get_reason() is None
 
-    @pytest.mark.parametrize('reason', [object(), 1.0, u'foo'])
+    @pytest.mark.parametrize("reason", [object(), 1.0, u"foo"])
     def test_set_reason_wrong_args(self, reason):
         """
         `Revoked.set_reason` raises `TypeError` if called with an argument
@@ -3106,13 +3207,14 @@ class TestRevoked(object):
         """
         revoked = Revoked()
         with pytest.raises(ValueError):
-            revoked.set_reason(b'blue')
+            revoked.set_reason(b"blue")
 
 
 class TestCRL(object):
     """
     Tests for `OpenSSL.crypto.CRL`.
     """
+
     cert = load_certificate(FILETYPE_PEM, cleartextCertificatePEM)
     pkey = load_privatekey(FILETYPE_PEM, cleartextPrivateKeyPEM)
 
@@ -3121,9 +3223,11 @@ class TestCRL(object):
     intermediate_cert = load_certificate(FILETYPE_PEM, intermediate_cert_pem)
     intermediate_key = load_privatekey(FILETYPE_PEM, intermediate_key_pem)
     intermediate_server_cert = load_certificate(
-        FILETYPE_PEM, intermediate_server_cert_pem)
+        FILETYPE_PEM, intermediate_server_cert_pem
+    )
     intermediate_server_key = load_privatekey(
-        FILETYPE_PEM, intermediate_server_key_pem)
+        FILETYPE_PEM, intermediate_server_key_pem
+    )
 
     def test_construction(self):
         """
@@ -3142,8 +3246,8 @@ class TestCRL(object):
         revoked = Revoked()
         now = datetime.now().strftime("%Y%m%d%H%M%SZ").encode("ascii")
         revoked.set_rev_date(now)
-        revoked.set_serial(b'3ab')
-        revoked.set_reason(b'sUpErSeDEd')
+        revoked.set_serial(b"3ab")
+        revoked.set_reason(b"sUpErSeDEd")
         crl.add_revoked(revoked)
         return crl
 
@@ -3160,13 +3264,17 @@ class TestCRL(object):
         crl = x509.load_pem_x509_crl(dumped_crl, backend)
         revoked = crl.get_revoked_certificate_by_serial_number(0x03AB)
         assert revoked is not None
-        assert crl.issuer == x509.Name([
-            x509.NameAttribute(x509.NameOID.COUNTRY_NAME, u"US"),
-            x509.NameAttribute(x509.NameOID.STATE_OR_PROVINCE_NAME, u"IL"),
-            x509.NameAttribute(x509.NameOID.LOCALITY_NAME, u"Chicago"),
-            x509.NameAttribute(x509.NameOID.ORGANIZATION_NAME, u"Testing"),
-            x509.NameAttribute(x509.NameOID.COMMON_NAME, u"Testing Root CA"),
-        ])
+        assert crl.issuer == x509.Name(
+            [
+                x509.NameAttribute(x509.NameOID.COUNTRY_NAME, u"US"),
+                x509.NameAttribute(x509.NameOID.STATE_OR_PROVINCE_NAME, u"IL"),
+                x509.NameAttribute(x509.NameOID.LOCALITY_NAME, u"Chicago"),
+                x509.NameAttribute(x509.NameOID.ORGANIZATION_NAME, u"Testing"),
+                x509.NameAttribute(
+                    x509.NameOID.COMMON_NAME, u"Testing Root CA"
+                ),
+            ]
+        )
 
     def test_export_der(self):
         """
@@ -3183,13 +3291,17 @@ class TestCRL(object):
         crl = x509.load_der_x509_crl(dumped_crl, backend)
         revoked = crl.get_revoked_certificate_by_serial_number(0x03AB)
         assert revoked is not None
-        assert crl.issuer == x509.Name([
-            x509.NameAttribute(x509.NameOID.COUNTRY_NAME, u"US"),
-            x509.NameAttribute(x509.NameOID.STATE_OR_PROVINCE_NAME, u"IL"),
-            x509.NameAttribute(x509.NameOID.LOCALITY_NAME, u"Chicago"),
-            x509.NameAttribute(x509.NameOID.ORGANIZATION_NAME, u"Testing"),
-            x509.NameAttribute(x509.NameOID.COMMON_NAME, u"Testing Root CA"),
-        ])
+        assert crl.issuer == x509.Name(
+            [
+                x509.NameAttribute(x509.NameOID.COUNTRY_NAME, u"US"),
+                x509.NameAttribute(x509.NameOID.STATE_OR_PROVINCE_NAME, u"IL"),
+                x509.NameAttribute(x509.NameOID.LOCALITY_NAME, u"Chicago"),
+                x509.NameAttribute(x509.NameOID.ORGANIZATION_NAME, u"Testing"),
+                x509.NameAttribute(
+                    x509.NameOID.COMMON_NAME, u"Testing Root CA"
+                ),
+            ]
+        )
 
     # Flaky because we compare the output of running commands which sometimes
     # varies by 1 second
@@ -3206,8 +3318,14 @@ class TestCRL(object):
             self.cert, self.pkey, FILETYPE_ASN1, digest=b"md5"
         )
         text = _runopenssl(
-            dumped_crl, b"crl", b"-noout", b"-text", b"-inform", b"DER",
-            b"-nameopt", b""
+            dumped_crl,
+            b"crl",
+            b"-noout",
+            b"-text",
+            b"-inform",
+            b"DER",
+            b"-nameopt",
+            b"",
         )
 
         # text format
@@ -3224,7 +3342,7 @@ class TestCRL(object):
         crl = self._get_crl()
         dumped_crl = crl.export(self.cert, self.pkey, digest=b"sha1")
         text = _runopenssl(dumped_crl, b"crl", b"-noout", b"-text")
-        text.index(b'Signature Algorithm: sha1')
+        text.index(b"Signature Algorithm: sha1")
 
     def test_export_md5_digest(self):
         """
@@ -3237,7 +3355,7 @@ class TestCRL(object):
         assert 0 == len(catcher)
         dumped_crl = crl.export(self.cert, self.pkey, digest=b"md5")
         text = _runopenssl(dumped_crl, b"crl", b"-noout", b"-text")
-        text.index(b'Signature Algorithm: md5')
+        text.index(b"Signature Algorithm: md5")
 
     def test_export_default_digest(self):
         """
@@ -3303,7 +3421,8 @@ class TestCRL(object):
         crl = CRL()
         with pytest.raises(ValueError):
             crl.export(
-                self.cert, self.pkey, FILETYPE_PEM, 10, b"strange-digest")
+                self.cert, self.pkey, FILETYPE_PEM, 10, b"strange-digest"
+            )
 
     def test_get_revoked(self):
         """
@@ -3315,18 +3434,18 @@ class TestCRL(object):
         revoked = Revoked()
         now = datetime.now().strftime("%Y%m%d%H%M%SZ").encode("ascii")
         revoked.set_rev_date(now)
-        revoked.set_serial(b'3ab')
+        revoked.set_serial(b"3ab")
         crl.add_revoked(revoked)
-        revoked.set_serial(b'100')
-        revoked.set_reason(b'sUpErSeDEd')
+        revoked.set_serial(b"100")
+        revoked.set_reason(b"sUpErSeDEd")
         crl.add_revoked(revoked)
 
         revs = crl.get_revoked()
         assert len(revs) == 2
         assert type(revs[0]) == Revoked
         assert type(revs[1]) == Revoked
-        assert revs[0].get_serial() == b'03AB'
-        assert revs[1].get_serial() == b'0100'
+        assert revs[0].get_serial() == b"03AB"
+        assert revs[1].get_serial() == b"0100"
         assert revs[0].get_rev_date() == now
         assert revs[1].get_rev_date() == now
 
@@ -3338,19 +3457,19 @@ class TestCRL(object):
         crl = load_crl(FILETYPE_PEM, crlData)
         revs = crl.get_revoked()
         assert len(revs) == 2
-        assert revs[0].get_serial() == b'03AB'
+        assert revs[0].get_serial() == b"03AB"
         assert revs[0].get_reason() is None
-        assert revs[1].get_serial() == b'0100'
-        assert revs[1].get_reason() == b'Superseded'
+        assert revs[1].get_serial() == b"0100"
+        assert revs[1].get_reason() == b"Superseded"
 
         der = _runopenssl(crlData, b"crl", b"-outform", b"DER")
         crl = load_crl(FILETYPE_ASN1, der)
         revs = crl.get_revoked()
         assert len(revs) == 2
-        assert revs[0].get_serial() == b'03AB'
+        assert revs[0].get_serial() == b"03AB"
         assert revs[0].get_reason() is None
-        assert revs[1].get_serial() == b'0100'
-        assert revs[1].get_reason() == b'Superseded'
+        assert revs[1].get_serial() == b"0100"
+        assert revs[1].get_reason() == b"Superseded"
 
     def test_load_crl_bad_filetype(self):
         """
@@ -3375,7 +3494,7 @@ class TestCRL(object):
         """
         crl = load_crl(FILETYPE_PEM, crlData)
         assert isinstance(crl.get_issuer(), X509Name)
-        assert crl.get_issuer().CN == 'Testing Root CA'
+        assert crl.get_issuer().CN == "Testing Root CA"
 
     def test_dump_crl(self):
         """
@@ -3398,15 +3517,15 @@ class TestCRL(object):
             # FIXME: This string splicing is an unfortunate implementation
             # detail that has been reported in
             # https://github.com/pyca/pyopenssl/issues/258
-            serial = hex(cert.get_serial_number())[2:].encode('utf-8')
+            serial = hex(cert.get_serial_number())[2:].encode("utf-8")
             revoked.set_serial(serial)
-            revoked.set_reason(b'unspecified')
-            revoked.set_rev_date(b'20140601000000Z')
+            revoked.set_reason(b"unspecified")
+            revoked.set_rev_date(b"20140601000000Z")
             crl.add_revoked(revoked)
         crl.set_version(1)
-        crl.set_lastUpdate(b'20140601000000Z')
-        crl.set_nextUpdate(b'20180601000000Z')
-        crl.sign(issuer_cert, issuer_key, digest=b'sha512')
+        crl.set_lastUpdate(b"20140601000000Z")
+        crl.set_nextUpdate(b"20180601000000Z")
+        crl.sign(issuer_cert, issuer_key, digest=b"sha512")
         return crl
 
     def test_verify_with_revoked(self):
@@ -3418,17 +3537,20 @@ class TestCRL(object):
         store.add_cert(self.root_cert)
         store.add_cert(self.intermediate_cert)
         root_crl = self._make_test_crl(
-            self.root_cert, self.root_key, certs=[self.intermediate_cert])
+            self.root_cert, self.root_key, certs=[self.intermediate_cert]
+        )
         intermediate_crl = self._make_test_crl(
-            self.intermediate_cert, self.intermediate_key, certs=[])
+            self.intermediate_cert, self.intermediate_key, certs=[]
+        )
         store.add_crl(root_crl)
         store.add_crl(intermediate_crl)
         store.set_flags(
-            X509StoreFlags.CRL_CHECK | X509StoreFlags.CRL_CHECK_ALL)
+            X509StoreFlags.CRL_CHECK | X509StoreFlags.CRL_CHECK_ALL
+        )
         store_ctx = X509StoreContext(store, self.intermediate_server_cert)
         with pytest.raises(X509StoreContextError) as err:
             store_ctx.verify_certificate()
-        assert err.value.args[0][2] == 'certificate revoked'
+        assert err.value.args[0][2] == "certificate revoked"
 
     def test_verify_with_missing_crl(self):
         """
@@ -3439,15 +3561,17 @@ class TestCRL(object):
         store.add_cert(self.root_cert)
         store.add_cert(self.intermediate_cert)
         root_crl = self._make_test_crl(
-            self.root_cert, self.root_key, certs=[self.intermediate_cert])
+            self.root_cert, self.root_key, certs=[self.intermediate_cert]
+        )
         store.add_crl(root_crl)
         store.set_flags(
-            X509StoreFlags.CRL_CHECK | X509StoreFlags.CRL_CHECK_ALL)
+            X509StoreFlags.CRL_CHECK | X509StoreFlags.CRL_CHECK_ALL
+        )
         store_ctx = X509StoreContext(store, self.intermediate_server_cert)
         with pytest.raises(X509StoreContextError) as err:
             store_ctx.verify_certificate()
-        assert err.value.args[0][2] == 'unable to get certificate CRL'
-        assert err.value.certificate.get_subject().CN == 'intermediate-service'
+        assert err.value.args[0][2] == "unable to get certificate CRL"
+        assert err.value.certificate.get_subject().CN == "intermediate-service"
 
     def test_convert_from_cryptography(self):
         crypto_crl = x509.load_pem_x509_crl(crlData, backend)
@@ -3468,10 +3592,12 @@ class TestX509StoreContext(object):
     """
     Tests for `OpenSSL.crypto.X509StoreContext`.
     """
+
     root_cert = load_certificate(FILETYPE_PEM, root_cert_pem)
     intermediate_cert = load_certificate(FILETYPE_PEM, intermediate_cert_pem)
     intermediate_server_cert = load_certificate(
-        FILETYPE_PEM, intermediate_server_cert_pem)
+        FILETYPE_PEM, intermediate_server_cert_pem
+    )
 
     def test_valid(self):
         """
@@ -3516,8 +3642,8 @@ class TestX509StoreContext(object):
         with pytest.raises(X509StoreContextError) as exc:
             store_ctx.verify_certificate()
 
-        assert exc.value.args[0][2] == 'self signed certificate'
-        assert exc.value.certificate.get_subject().CN == 'Testing Root CA'
+        assert exc.value.args[0][2] == "self signed certificate"
+        assert exc.value.certificate.get_subject().CN == "Testing Root CA"
 
     def test_invalid_chain_no_root(self):
         """
@@ -3531,8 +3657,8 @@ class TestX509StoreContext(object):
         with pytest.raises(X509StoreContextError) as exc:
             store_ctx.verify_certificate()
 
-        assert exc.value.args[0][2] == 'unable to get issuer certificate'
-        assert exc.value.certificate.get_subject().CN == 'intermediate'
+        assert exc.value.args[0][2] == "unable to get issuer certificate"
+        assert exc.value.certificate.get_subject().CN == "intermediate"
 
     def test_invalid_chain_no_intermediate(self):
         """
@@ -3546,8 +3672,8 @@ class TestX509StoreContext(object):
         with pytest.raises(X509StoreContextError) as exc:
             store_ctx.verify_certificate()
 
-        assert exc.value.args[0][2] == 'unable to get local issuer certificate'
-        assert exc.value.certificate.get_subject().CN == 'intermediate-service'
+        assert exc.value.args[0][2] == "unable to get local issuer certificate"
+        assert exc.value.certificate.get_subject().CN == "intermediate-service"
 
     def test_modification_pre_verify(self):
         """
@@ -3564,8 +3690,8 @@ class TestX509StoreContext(object):
         with pytest.raises(X509StoreContextError) as exc:
             store_ctx.verify_certificate()
 
-        assert exc.value.args[0][2] == 'unable to get issuer certificate'
-        assert exc.value.certificate.get_subject().CN == 'intermediate'
+        assert exc.value.args[0][2] == "unable to get issuer certificate"
+        assert exc.value.certificate.get_subject().CN == "intermediate"
 
         store_ctx.set_store(store_good)
         assert store_ctx.verify_certificate() is None
@@ -3581,7 +3707,7 @@ class TestX509StoreContext(object):
 
         expire_time = self.intermediate_server_cert.get_notAfter()
         expire_datetime = datetime.strptime(
-            expire_time.decode('utf-8'), '%Y%m%d%H%M%SZ'
+            expire_time.decode("utf-8"), "%Y%m%d%H%M%SZ"
         )
         store.set_time(expire_datetime)
 
@@ -3589,7 +3715,7 @@ class TestX509StoreContext(object):
         with pytest.raises(X509StoreContextError) as exc:
             store_ctx.verify_certificate()
 
-        assert exc.value.args[0][2] == 'certificate has expired'
+        assert exc.value.args[0][2] == "certificate has expired"
 
 
 class TestSignVerify(object):
@@ -3606,7 +3732,8 @@ class TestSignVerify(object):
             b"thirteen. Winston Smith, his chin nuzzled into his breast in an "
             b"effort to escape the vile wind, slipped quickly through the "
             b"glass doors of Victory Mansions, though not quickly enough to "
-            b"prevent a swirl of gritty dust from entering along with him.")
+            b"prevent a swirl of gritty dust from entering along with him."
+        )
 
         # sign the content with this private key
         priv_key = load_privatekey(FILETYPE_PEM, root_key_pem)
@@ -3615,7 +3742,7 @@ class TestSignVerify(object):
         # certificate unrelated to priv_key, used to trigger an error
         bad_cert = load_certificate(FILETYPE_PEM, server_cert_pem)
 
-        for digest in ['md5', 'sha1']:
+        for digest in ["md5", "sha1"]:
             sig = sign(priv_key, content, digest)
 
             # Verify the signature of content, will throw an exception if
@@ -3654,22 +3781,20 @@ class TestSignVerify(object):
 
         priv_key = load_privatekey(FILETYPE_PEM, root_key_pem)
         cert = load_certificate(FILETYPE_PEM, root_cert_pem)
-        for digest in ['md5', 'sha1']:
+        for digest in ["md5", "sha1"]:
             with pytest.warns(DeprecationWarning) as w:
                 simplefilter("always")
                 sig = sign(priv_key, content, digest)
-            assert (
-                "{0} for data is no longer accepted, use bytes".format(
-                    WARNING_TYPE_EXPECTED
-                ) == str(w[-1].message))
+            assert "{0} for data is no longer accepted, use bytes".format(
+                WARNING_TYPE_EXPECTED
+            ) == str(w[-1].message)
 
             with pytest.warns(DeprecationWarning) as w:
                 simplefilter("always")
                 verify(cert, sig, content, digest)
-            assert (
-                "{0} for data is no longer accepted, use bytes".format(
-                    WARNING_TYPE_EXPECTED
-                ) == str(w[-1].message))
+            assert "{0} for data is no longer accepted, use bytes".format(
+                WARNING_TYPE_EXPECTED
+            ) == str(w[-1].message)
 
     def test_sign_verify_ecdsa(self):
         """
@@ -3708,7 +3833,8 @@ class TestSignVerify(object):
             b"thirteen. Winston Smith, his chin nuzzled into his breast in an "
             b"effort to escape the vile wind, slipped quickly through the "
             b"glass doors of Victory Mansions, though not quickly enough to "
-            b"prevent a swirl of gritty dust from entering along with him.")
+            b"prevent a swirl of gritty dust from entering along with him."
+        )
 
         priv_key = load_privatekey(FILETYPE_PEM, large_key_pem)
         sign(priv_key, content, "sha1")
@@ -3780,6 +3906,7 @@ class TestEllipticCurveEquality(EqualityTestsMixin):
     """
     Tests `_EllipticCurve`'s implementation of ``==`` and ``!=``.
     """
+
     curve_factory = EllipticCurveFactory()
 
     if curve_factory.curve_name is None:
@@ -3804,6 +3931,7 @@ class TestEllipticCurveHash(object):
     Tests for `_EllipticCurve`'s implementation of hashing (thus use as
     an item in a `dict` or `set`).
     """
+
     curve_factory = EllipticCurveFactory()
 
     if curve_factory.curve_name is None:
@@ -3824,7 +3952,7 @@ class TestEllipticCurveHash(object):
         does not contain that curve.
         """
         curve = get_elliptic_curve(self.curve_factory.curve_name)
-        curves = set([
-            get_elliptic_curve(self.curve_factory.another_curve_name)
-        ])
+        curves = set(
+            [get_elliptic_curve(self.curve_factory.another_curve_name)]
+        )
         assert curve not in curves
diff --git a/tests/test_rand.py b/tests/test_rand.py
index e04a24c..763d711 100644
--- a/tests/test_rand.py
+++ b/tests/test_rand.py
@@ -11,11 +11,7 @@ from OpenSSL import rand
 
 
 class TestRand(object):
-
-    @pytest.mark.parametrize('args', [
-        (b"foo", None),
-        (None, 3),
-    ])
+    @pytest.mark.parametrize("args", [(b"foo", None), (None, 3)])
     def test_add_wrong_args(self, args):
         """
         `OpenSSL.rand.add` raises `TypeError` if called with arguments not of
@@ -28,7 +24,7 @@ class TestRand(object):
         """
         `OpenSSL.rand.add` adds entropy to the PRNG.
         """
-        rand.add(b'hamburger', 3)
+        rand.add(b"hamburger", 3)
 
     def test_status(self):
         """
diff --git a/tests/test_ssl.py b/tests/test_ssl.py
index 2cee928..ba5b638 100644
--- a/tests/test_ssl.py
+++ b/tests/test_ssl.py
@@ -11,7 +11,13 @@ import uuid
 
 from gc import collect, get_referrers
 from errno import (
-    EAFNOSUPPORT, ECONNREFUSED, EINPROGRESS, EWOULDBLOCK, EPIPE, ESHUTDOWN)
+    EAFNOSUPPORT,
+    ECONNREFUSED,
+    EINPROGRESS,
+    EWOULDBLOCK,
+    EPIPE,
+    ESHUTDOWN,
+)
 from sys import platform, getfilesystemencoding
 from socket import AF_INET, AF_INET6, MSG_PEEK, SHUT_RDWR, error, socket
 from os import makedirs
@@ -45,49 +51,93 @@ from OpenSSL.SSL import OPENSSL_VERSION_NUMBER, SSLEAY_VERSION, SSLEAY_CFLAGS
 from OpenSSL.SSL import SSLEAY_PLATFORM, SSLEAY_DIR, SSLEAY_BUILT_ON
 from OpenSSL.SSL import SENT_SHUTDOWN, RECEIVED_SHUTDOWN
 from OpenSSL.SSL import (
-    SSLv2_METHOD, SSLv3_METHOD, SSLv23_METHOD, TLSv1_METHOD,
-    TLSv1_1_METHOD, TLSv1_2_METHOD)
+    SSLv2_METHOD,
+    SSLv3_METHOD,
+    SSLv23_METHOD,
+    TLSv1_METHOD,
+    TLSv1_1_METHOD,
+    TLSv1_2_METHOD,
+)
 from OpenSSL.SSL import OP_SINGLE_DH_USE, OP_NO_SSLv2, OP_NO_SSLv3
 from OpenSSL.SSL import (
-    VERIFY_PEER, VERIFY_FAIL_IF_NO_PEER_CERT, VERIFY_CLIENT_ONCE, VERIFY_NONE)
+    VERIFY_PEER,
+    VERIFY_FAIL_IF_NO_PEER_CERT,
+    VERIFY_CLIENT_ONCE,
+    VERIFY_NONE,
+)
 
 from OpenSSL import SSL
 from OpenSSL.SSL import (
-    SESS_CACHE_OFF, SESS_CACHE_CLIENT, SESS_CACHE_SERVER, SESS_CACHE_BOTH,
-    SESS_CACHE_NO_AUTO_CLEAR, SESS_CACHE_NO_INTERNAL_LOOKUP,
-    SESS_CACHE_NO_INTERNAL_STORE, SESS_CACHE_NO_INTERNAL)
+    SESS_CACHE_OFF,
+    SESS_CACHE_CLIENT,
+    SESS_CACHE_SERVER,
+    SESS_CACHE_BOTH,
+    SESS_CACHE_NO_AUTO_CLEAR,
+    SESS_CACHE_NO_INTERNAL_LOOKUP,
+    SESS_CACHE_NO_INTERNAL_STORE,
+    SESS_CACHE_NO_INTERNAL,
+)
 
 from OpenSSL.SSL import (
-    Error, SysCallError, WantReadError, WantWriteError, ZeroReturnError)
-from OpenSSL.SSL import (
-    Context, Session, Connection, SSLeay_version)
+    Error,
+    SysCallError,
+    WantReadError,
+    WantWriteError,
+    ZeroReturnError,
+)
+from OpenSSL.SSL import Context, Session, Connection, SSLeay_version
 from OpenSSL.SSL import _make_requires
 
 from OpenSSL._util import ffi as _ffi, lib as _lib
 
 from OpenSSL.SSL import (
-    OP_NO_QUERY_MTU, OP_COOKIE_EXCHANGE, OP_NO_TICKET, OP_NO_COMPRESSION,
-    MODE_RELEASE_BUFFERS, NO_OVERLAPPING_PROTOCOLS)
+    OP_NO_QUERY_MTU,
+    OP_COOKIE_EXCHANGE,
+    OP_NO_TICKET,
+    OP_NO_COMPRESSION,
+    MODE_RELEASE_BUFFERS,
+    NO_OVERLAPPING_PROTOCOLS,
+)
 
 from OpenSSL.SSL import (
-    SSL_ST_CONNECT, SSL_ST_ACCEPT, SSL_ST_MASK,
-    SSL_CB_LOOP, SSL_CB_EXIT, SSL_CB_READ, SSL_CB_WRITE, SSL_CB_ALERT,
-    SSL_CB_READ_ALERT, SSL_CB_WRITE_ALERT, SSL_CB_ACCEPT_LOOP,
-    SSL_CB_ACCEPT_EXIT, SSL_CB_CONNECT_LOOP, SSL_CB_CONNECT_EXIT,
-    SSL_CB_HANDSHAKE_START, SSL_CB_HANDSHAKE_DONE)
+    SSL_ST_CONNECT,
+    SSL_ST_ACCEPT,
+    SSL_ST_MASK,
+    SSL_CB_LOOP,
+    SSL_CB_EXIT,
+    SSL_CB_READ,
+    SSL_CB_WRITE,
+    SSL_CB_ALERT,
+    SSL_CB_READ_ALERT,
+    SSL_CB_WRITE_ALERT,
+    SSL_CB_ACCEPT_LOOP,
+    SSL_CB_ACCEPT_EXIT,
+    SSL_CB_CONNECT_LOOP,
+    SSL_CB_CONNECT_EXIT,
+    SSL_CB_HANDSHAKE_START,
+    SSL_CB_HANDSHAKE_DONE,
+)
 
 try:
     from OpenSSL.SSL import (
-        SSL_ST_INIT, SSL_ST_BEFORE, SSL_ST_OK, SSL_ST_RENEGOTIATE
+        SSL_ST_INIT,
+        SSL_ST_BEFORE,
+        SSL_ST_OK,
+        SSL_ST_RENEGOTIATE,
     )
 except ImportError:
     SSL_ST_INIT = SSL_ST_BEFORE = SSL_ST_OK = SSL_ST_RENEGOTIATE = None
 
 from .util import WARNING_TYPE_EXPECTED, NON_ASCII, is_consistent_type
 from .test_crypto import (
-    cleartextCertificatePEM, cleartextPrivateKeyPEM,
-    client_cert_pem, client_key_pem, server_cert_pem, server_key_pem,
-    root_cert_pem)
+    cleartextCertificatePEM,
+    cleartextPrivateKeyPEM,
+    client_cert_pem,
+    client_key_pem,
+    server_cert_pem,
+    server_key_pem,
+    root_cert_pem,
+)
 
 
 # openssl dhparam 1024 -out dh-1024.pem (note that 1024 is a small number of
@@ -148,7 +198,7 @@ def socket_pair():
     """
     # Connect a pair of sockets
     port = socket_any_family()
-    port.bind(('', 0))
+    port.bind(("", 0))
     port.listen(1)
     client = socket(port.family)
     client.setblocking(False)
@@ -191,8 +241,8 @@ def _create_certificate_chain():
         2. A new intermediate certificate signed by cacert (icert)
         3. A new server certificate signed by icert (scert)
     """
-    caext = X509Extension(b'basicConstraints', False, b'CA:true')
-    not_after_date = (datetime.date.today() + datetime.timedelta(days=365))
+    caext = X509Extension(b"basicConstraints", False, b"CA:true")
+    not_after_date = datetime.date.today() + datetime.timedelta(days=365)
     not_after = not_after_date.strftime("%Y%m%d%H%M%SZ").encode("ascii")
 
     # Step 1
@@ -233,8 +283,9 @@ def _create_certificate_chain():
     scert.set_pubkey(skey)
     scert.set_notBefore(b"20000101000000Z")
     scert.set_notAfter(not_after)
-    scert.add_extensions([
-        X509Extension(b'basicConstraints', True, b'CA:false')])
+    scert.add_extensions(
+        [X509Extension(b"basicConstraints", True, b"CA:false")]
+    )
     scert.set_serial_number(0)
     scert.sign(ikey, "sha1")
 
@@ -293,8 +344,10 @@ def interact_in_memory(client_conn, server_conn):
 
         # Copy stuff from each side's send buffer to the other side's
         # receive buffer.
-        for (read, write) in [(client_conn, server_conn),
-                              (server_conn, client_conn)]:
+        for (read, write) in [
+            (client_conn, server_conn),
+            (server_conn, client_conn),
+        ]:
 
             # Give the side a chance to generate some more bytes, or succeed.
             try:
@@ -344,6 +397,7 @@ class TestVersion(object):
     Tests for version information exposed by `OpenSSL.SSL.SSLeay_version` and
     `OpenSSL.SSL.OPENSSL_VERSION_NUMBER`.
     """
+
     def test_OPENSSL_VERSION_NUMBER(self):
         """
         `OPENSSL_VERSION_NUMBER` is an integer with status in the low byte and
@@ -357,8 +411,13 @@ class TestVersion(object):
         number of version strings based on that indicator.
         """
         versions = {}
-        for t in [SSLEAY_VERSION, SSLEAY_CFLAGS, SSLEAY_BUILT_ON,
-                  SSLEAY_PLATFORM, SSLEAY_DIR]:
+        for t in [
+            SSLEAY_VERSION,
+            SSLEAY_CFLAGS,
+            SSLEAY_BUILT_ON,
+            SSLEAY_PLATFORM,
+            SSLEAY_DIR,
+        ]:
             version = SSLeay_version(t)
             versions[version] = t
             assert isinstance(version, bytes)
@@ -371,19 +430,17 @@ def ca_file(tmpdir):
     Create a valid PEM file with CA certificates and return the path.
     """
     key = rsa.generate_private_key(
-        public_exponent=65537,
-        key_size=2048,
-        backend=default_backend()
+        public_exponent=65537, key_size=2048, backend=default_backend()
     )
     public_key = key.public_key()
 
     builder = x509.CertificateBuilder()
-    builder = builder.subject_name(x509.Name([
-        x509.NameAttribute(NameOID.COMMON_NAME, u"pyopenssl.org"),
-    ]))
-    builder = builder.issuer_name(x509.Name([
-        x509.NameAttribute(NameOID.COMMON_NAME, u"pyopenssl.org"),
-    ]))
+    builder = builder.subject_name(
+        x509.Name([x509.NameAttribute(NameOID.COMMON_NAME, u"pyopenssl.org")])
+    )
+    builder = builder.issuer_name(
+        x509.Name([x509.NameAttribute(NameOID.COMMON_NAME, u"pyopenssl.org")])
+    )
     one_day = datetime.timedelta(1, 0, 0)
     builder = builder.not_valid_before(datetime.datetime.today() - one_day)
     builder = builder.not_valid_after(datetime.datetime.today() + one_day)
@@ -394,15 +451,12 @@ def ca_file(tmpdir):
     )
 
     certificate = builder.sign(
-        private_key=key, algorithm=hashes.SHA256(),
-        backend=default_backend()
+        private_key=key, algorithm=hashes.SHA256(), backend=default_backend()
     )
 
     ca_file = tmpdir.join("test.pem")
     ca_file.write_binary(
-        certificate.public_bytes(
-            encoding=serialization.Encoding.PEM,
-        )
+        certificate.public_bytes(encoding=serialization.Encoding.PEM,)
     )
 
     return str(ca_file).encode("ascii")
@@ -420,10 +474,11 @@ class TestContext(object):
     """
     Unit tests for `OpenSSL.SSL.Context`.
     """
-    @pytest.mark.parametrize("cipher_string", [
-        b"hello world:AES128-SHA",
-        u"hello world:AES128-SHA",
-    ])
+
+    @pytest.mark.parametrize(
+        "cipher_string",
+        [b"hello world:AES128-SHA", u"hello world:AES128-SHA"],
+    )
     def test_set_cipher_list(self, context, cipher_string):
         """
         `Context.set_cipher_list` accepts both byte and unicode strings
@@ -453,14 +508,8 @@ class TestContext(object):
         with pytest.raises(Error) as excinfo:
             context.set_cipher_list(b"imaginary-cipher")
         assert excinfo.value.args == (
-                [
-                    (
-                        'SSL routines',
-                        'SSL_CTX_set_cipher_list',
-                        'no cipher match',
-                    ),
-                ],
-            )
+            [("SSL routines", "SSL_CTX_set_cipher_list", "no cipher match",)],
+        )
 
     def test_load_client_ca(self, context, ca_file):
         """
@@ -484,9 +533,7 @@ class TestContext(object):
         """
         Passing the path as unicode raises a warning but works.
         """
-        pytest.deprecated_call(
-            context.load_client_ca, ca_file.decode("ascii")
-        )
+        pytest.deprecated_call(context.load_client_ca, ca_file.decode("ascii"))
 
     def test_set_session_id(self, context):
         """
@@ -502,9 +549,11 @@ class TestContext(object):
             context.set_session_id(b"abc" * 1000)
 
         assert [
-            ("SSL routines",
-             "SSL_CTX_set_session_id_context",
-             "ssl session id context too long")
+            (
+                "SSL routines",
+                "SSL_CTX_set_session_id_context",
+                "ssl session id context too long",
+            )
         ] == e.value.args[0]
 
     def test_set_session_id_unicode(self, context):
@@ -542,7 +591,7 @@ class TestContext(object):
         """
         `Context` can be used to create instances of that type.
         """
-        assert is_consistent_type(Context, 'Context', TLSv1_METHOD)
+        assert is_consistent_type(Context, "Context", TLSv1_METHOD)
 
     def test_use_privatekey(self):
         """
@@ -573,14 +622,12 @@ class TestContext(object):
         key.generate_key(TYPE_RSA, 512)
 
         with open(pemfile, "wt") as pem:
-            pem.write(
-                dump_privatekey(FILETYPE_PEM, key).decode("ascii")
-            )
+            pem.write(dump_privatekey(FILETYPE_PEM, key).decode("ascii"))
 
         ctx = Context(TLSv1_METHOD)
         ctx.use_privatekey_file(pemfile, filetype)
 
-    @pytest.mark.parametrize('filetype', [object(), "", None, 1.0])
+    @pytest.mark.parametrize("filetype", [object(), "", None, 1.0])
     def test_wrong_privatekey_file_wrong_args(self, tmpfile, filetype):
         """
         `Context.use_privatekey_file` raises `TypeError` when called with
@@ -596,8 +643,7 @@ class TestContext(object):
         instance giving the file name to ``Context.use_privatekey_file``.
         """
         self._use_privatekey_file_test(
-            tmpfile + NON_ASCII.encode(getfilesystemencoding()),
-            FILETYPE_PEM,
+            tmpfile + NON_ASCII.encode(getfilesystemencoding()), FILETYPE_PEM,
         )
 
     def test_use_privatekey_file_unicode(self, tmpfile):
@@ -606,8 +652,7 @@ class TestContext(object):
         instance giving the file name to ``Context.use_privatekey_file``.
         """
         self._use_privatekey_file_test(
-            tmpfile.decode(getfilesystemencoding()) + NON_ASCII,
-            FILETYPE_PEM,
+            tmpfile.decode(getfilesystemencoding()) + NON_ASCII, FILETYPE_PEM,
         )
 
     def test_use_certificate_wrong_args(self):
@@ -814,8 +859,8 @@ class TestContext(object):
         key = PKey()
         key.generate_key(TYPE_RSA, 512)
         pem = dump_privatekey(FILETYPE_PEM, key, "blowfish", passphrase)
-        with open(tmpfile, 'w') as fObj:
-            fObj.write(pem.decode('ascii'))
+        with open(tmpfile, "w") as fObj:
+            fObj.write(pem.decode("ascii"))
         return tmpfile
 
     def test_set_passwd_cb_wrong_args(self):
@@ -839,6 +884,7 @@ class TestContext(object):
         def passphraseCallback(maxlen, verify, extra):
             calledWith.append((maxlen, verify, extra))
             return passphrase
+
         context = Context(TLSv1_METHOD)
         context.set_passwd_cb(passphraseCallback)
         context.use_privatekey_file(pemFile)
@@ -926,12 +972,15 @@ class TestContext(object):
 
         def info(conn, where, ret):
             called.append((conn, where, ret))
+
         context = Context(TLSv1_METHOD)
         context.set_info_callback(info)
         context.use_certificate(
-            load_certificate(FILETYPE_PEM, cleartextCertificatePEM))
+            load_certificate(FILETYPE_PEM, cleartextCertificatePEM)
+        )
         context.use_privatekey(
-            load_privatekey(FILETYPE_PEM, cleartextPrivateKeyPEM))
+            load_privatekey(FILETYPE_PEM, cleartextPrivateKeyPEM)
+        )
 
         serverSSL = Connection(context, server)
         serverSSL.set_accept_state()
@@ -944,10 +993,13 @@ class TestContext(object):
         # assert it is called with the right Connection instance.  It would
         # also be good to assert *something* about `where` and `ret`.
         notConnections = [
-            conn for (conn, where, ret) in called
-            if not isinstance(conn, Connection)]
-        assert [] == notConnections, (
-            "Some info callback arguments were not Connection instances.")
+            conn
+            for (conn, where, ret) in called
+            if not isinstance(conn, Connection)
+        ]
+        assert (
+            [] == notConnections
+        ), "Some info callback arguments were not Connection instances."
 
     def _load_verify_locations_test(self, *args):
         """
@@ -963,16 +1015,19 @@ class TestContext(object):
         # connection will fail.
         clientContext.set_verify(
             VERIFY_PEER,
-            lambda conn, cert, errno, depth, preverify_ok: preverify_ok)
+            lambda conn, cert, errno, depth, preverify_ok: preverify_ok,
+        )
 
         clientSSL = Connection(clientContext, client)
         clientSSL.set_connect_state()
 
         serverContext = Context(TLSv1_METHOD)
         serverContext.use_certificate(
-            load_certificate(FILETYPE_PEM, cleartextCertificatePEM))
+            load_certificate(FILETYPE_PEM, cleartextCertificatePEM)
+        )
         serverContext.use_privatekey(
-            load_privatekey(FILETYPE_PEM, cleartextPrivateKeyPEM))
+            load_privatekey(FILETYPE_PEM, cleartextPrivateKeyPEM)
+        )
 
         serverSSL = Connection(serverContext, server)
         serverSSL.set_accept_state()
@@ -984,7 +1039,7 @@ class TestContext(object):
         handshake(clientSSL, serverSSL)
 
         cert = clientSSL.get_peer_certificate()
-        assert cert.get_subject().CN == 'Testing Root CA'
+        assert cert.get_subject().CN == "Testing Root CA"
 
     def _load_verify_cafile(self, cafile):
         """
@@ -993,8 +1048,8 @@ class TestContext(object):
         certificate is used as a trust root for the purposes of verifying
         connections created using that `Context`.
         """
-        with open(cafile, 'w') as fObj:
-            fObj.write(cleartextCertificatePEM.decode('ascii'))
+        with open(cafile, "w") as fObj:
+            fObj.write(cleartextCertificatePEM.decode("ascii"))
 
         self._load_verify_locations_test(cafile)
 
@@ -1035,10 +1090,10 @@ class TestContext(object):
         # Hash values computed manually with c_rehash to avoid depending on
         # c_rehash in the test suite.  One is from OpenSSL 0.9.8, the other
         # from OpenSSL 1.0.0.
-        for name in [b'c7adac82.0', b'c3705638.0']:
+        for name in [b"c7adac82.0", b"c3705638.0"]:
             cafile = join_bytes_or_unicode(capath, name)
-            with open(cafile, 'w') as fObj:
-                fObj.write(cleartextCertificatePEM.decode('ascii'))
+            with open(cafile, "w") as fObj:
+                fObj.write(cleartextCertificatePEM.decode("ascii"))
 
         self._load_verify_locations_test(None, capath)
 
@@ -1074,7 +1129,7 @@ class TestContext(object):
     @pytest.mark.skipif(
         not platform.startswith("linux"),
         reason="Loading fallback paths is a linux-specific behavior to "
-        "accommodate pyca/cryptography manylinux1 wheels"
+        "accommodate pyca/cryptography manylinux1 wheels",
     )
     def test_fallback_default_verify_paths(self, monkeypatch):
         """
@@ -1092,12 +1147,12 @@ class TestContext(object):
         monkeypatch.setattr(
             SSL,
             "_CRYPTOGRAPHY_MANYLINUX1_CA_FILE",
-            _ffi.string(_lib.X509_get_default_cert_file())
+            _ffi.string(_lib.X509_get_default_cert_file()),
         )
         monkeypatch.setattr(
             SSL,
             "_CRYPTOGRAPHY_MANYLINUX1_CA_DIR",
-            _ffi.string(_lib.X509_get_default_cert_dir())
+            _ffi.string(_lib.X509_get_default_cert_dir()),
         )
         context.set_default_verify_paths()
         store = context.get_cert_store()
@@ -1127,9 +1182,9 @@ class TestContext(object):
         monkeypatch.setattr(
             _lib, "SSL_CTX_set_default_verify_paths", lambda x: 1
         )
-        dir_env_var = _ffi.string(
-            _lib.X509_get_default_cert_dir_env()
-        ).decode("ascii")
+        dir_env_var = _ffi.string(_lib.X509_get_default_cert_dir_env()).decode(
+            "ascii"
+        )
         file_env_var = _ffi.string(
             _lib.X509_get_default_cert_file_env()
         ).decode("ascii")
@@ -1138,16 +1193,14 @@ class TestContext(object):
         context.set_default_verify_paths()
 
         monkeypatch.setattr(
-            context,
-            "_fallback_default_verify_paths",
-            raiser(SystemError)
+            context, "_fallback_default_verify_paths", raiser(SystemError)
         )
         context.set_default_verify_paths()
 
     @pytest.mark.skipif(
         platform == "win32",
         reason="set_default_verify_paths appears not to work on Windows.  "
-        "See LP#404343 and LP#404344."
+        "See LP#404343 and LP#404344.",
     )
     def test_set_default_verify_paths(self):
         """
@@ -1165,7 +1218,8 @@ class TestContext(object):
         context.set_default_verify_paths()
         context.set_verify(
             VERIFY_PEER,
-            lambda conn, cert, errno, depth, preverify_ok: preverify_ok)
+            lambda conn, cert, errno, depth, preverify_ok: preverify_ok,
+        )
 
         client = socket_any_family()
         client.connect(("encrypted.google.com", 443))
@@ -1183,9 +1237,7 @@ class TestContext(object):
         """
         context = Context(TLSv1_METHOD)
         context._fallback_default_verify_paths([], [])
-        context._fallback_default_verify_paths(
-            ["/not/a/file"], ["/not/a/dir"]
-        )
+        context._fallback_default_verify_paths(["/not/a/file"], ["/not/a/dir"])
 
     def test_add_extra_chain_cert_invalid_cert(self):
         """
@@ -1225,9 +1277,11 @@ class TestContext(object):
         """
         serverContext = Context(TLSv1_METHOD)
         serverContext.use_privatekey(
-            load_privatekey(FILETYPE_PEM, cleartextPrivateKeyPEM))
+            load_privatekey(FILETYPE_PEM, cleartextPrivateKeyPEM)
+        )
         serverContext.use_certificate(
-            load_certificate(FILETYPE_PEM, cleartextCertificatePEM))
+            load_certificate(FILETYPE_PEM, cleartextCertificatePEM)
+        )
         serverConnection = Connection(serverContext, None)
 
         class VerifyCallback(object):
@@ -1254,9 +1308,11 @@ class TestContext(object):
         """
         serverContext = Context(TLSv1_METHOD)
         serverContext.use_privatekey(
-            load_privatekey(FILETYPE_PEM, cleartextPrivateKeyPEM))
+            load_privatekey(FILETYPE_PEM, cleartextPrivateKeyPEM)
+        )
         serverContext.use_certificate(
-            load_certificate(FILETYPE_PEM, cleartextCertificatePEM))
+            load_certificate(FILETYPE_PEM, cleartextCertificatePEM)
+        )
         serverConnection = Connection(serverContext, None)
 
         def verify_cb_get_subject(conn, cert, errnum, depth, ok):
@@ -1278,14 +1334,17 @@ class TestContext(object):
         """
         serverContext = Context(TLSv1_2_METHOD)
         serverContext.use_privatekey(
-            load_privatekey(FILETYPE_PEM, cleartextPrivateKeyPEM))
+            load_privatekey(FILETYPE_PEM, cleartextPrivateKeyPEM)
+        )
         serverContext.use_certificate(
-            load_certificate(FILETYPE_PEM, cleartextCertificatePEM))
+            load_certificate(FILETYPE_PEM, cleartextCertificatePEM)
+        )
 
         clientContext = Context(TLSv1_2_METHOD)
 
         def verify_callback(*args):
             raise Exception("silly verify failure")
+
         clientContext.set_verify(VERIFY_PEER, verify_callback)
 
         with pytest.raises(Exception) as exc:
@@ -1310,17 +1369,17 @@ class TestContext(object):
 
         # Dump the CA certificate to a file because that's the only way to load
         # it as a trusted CA in the client context.
-        for cert, name in [(cacert, 'ca.pem'),
-                           (icert, 'i.pem'),
-                           (scert, 's.pem')]:
-            with tmpdir.join(name).open('w') as f:
-                f.write(dump_certificate(FILETYPE_PEM, cert).decode('ascii'))
-
-        for key, name in [(cakey, 'ca.key'),
-                          (ikey, 'i.key'),
-                          (skey, 's.key')]:
-            with tmpdir.join(name).open('w') as f:
-                f.write(dump_privatekey(FILETYPE_PEM, key).decode('ascii'))
+        for cert, name in [
+            (cacert, "ca.pem"),
+            (icert, "i.pem"),
+            (scert, "s.pem"),
+        ]:
+            with tmpdir.join(name).open("w") as f:
+                f.write(dump_certificate(FILETYPE_PEM, cert).decode("ascii"))
+
+        for key, name in [(cakey, "ca.key"), (ikey, "i.key"), (skey, "s.key")]:
+            with tmpdir.join(name).open("w") as f:
+                f.write(dump_privatekey(FILETYPE_PEM, key).decode("ascii"))
 
         # Create the server context
         serverContext = Context(TLSv1_METHOD)
@@ -1332,7 +1391,8 @@ class TestContext(object):
         # Create the client
         clientContext = Context(TLSv1_METHOD)
         clientContext.set_verify(
-            VERIFY_PEER | VERIFY_FAIL_IF_NO_PEER_CERT, verify_cb)
+            VERIFY_PEER | VERIFY_FAIL_IF_NO_PEER_CERT, verify_cb
+        )
         clientContext.load_verify_locations(str(tmpdir.join("ca.pem")))
 
         # Try it out.
@@ -1356,14 +1416,14 @@ class TestContext(object):
         caFile = join_bytes_or_unicode(certdir, "ca.pem")
 
         # Write out the chain file.
-        with open(chainFile, 'wb') as fObj:
+        with open(chainFile, "wb") as fObj:
             # Most specific to least general.
             fObj.write(dump_certificate(FILETYPE_PEM, scert))
             fObj.write(dump_certificate(FILETYPE_PEM, icert))
             fObj.write(dump_certificate(FILETYPE_PEM, cacert))
 
-        with open(caFile, 'w') as fObj:
-            fObj.write(dump_certificate(FILETYPE_PEM, cacert).decode('ascii'))
+        with open(caFile, "w") as fObj:
+            fObj.write(dump_certificate(FILETYPE_PEM, cacert).decode("ascii"))
 
         serverContext = Context(TLSv1_METHOD)
         serverContext.use_certificate_chain_file(chainFile)
@@ -1371,7 +1431,8 @@ class TestContext(object):
 
         clientContext = Context(TLSv1_METHOD)
         clientContext.set_verify(
-            VERIFY_PEER | VERIFY_FAIL_IF_NO_PEER_CERT, verify_cb)
+            VERIFY_PEER | VERIFY_FAIL_IF_NO_PEER_CERT, verify_cb
+        )
         clientContext.load_verify_locations(caFile)
 
         self._handshake_test(serverContext, clientContext)
@@ -1423,10 +1484,11 @@ class TestContext(object):
         context = Context(TLSv1_METHOD)
         assert context.get_verify_mode() == 0
         context.set_verify(
-            VERIFY_PEER | VERIFY_CLIENT_ONCE, lambda *args: None)
+            VERIFY_PEER | VERIFY_CLIENT_ONCE, lambda *args: None
+        )
         assert context.get_verify_mode() == (VERIFY_PEER | VERIFY_CLIENT_ONCE)
 
-    @pytest.mark.parametrize('mode', [None, 1.0, object(), 'mode'])
+    @pytest.mark.parametrize("mode", [None, 1.0, object(), "mode"])
     def test_set_verify_wrong_mode_arg(self, mode):
         """
         `Context.set_verify` raises `TypeError` if the first argument is
@@ -1436,7 +1498,7 @@ class TestContext(object):
         with pytest.raises(TypeError):
             context.set_verify(mode=mode, callback=lambda *args: None)
 
-    @pytest.mark.parametrize('callback', [None, 1.0, 'mode', ('foo', 'bar')])
+    @pytest.mark.parametrize("callback", [None, 1.0, "mode", ("foo", "bar")])
     def test_set_verify_wrong_callable_arg(self, callback):
         """
         `Context.set_verify` raises `TypeError` if the second argument
@@ -1547,7 +1609,7 @@ class TestContext(object):
         """
         context = Context(TLSv1_METHOD)
         with pytest.raises(TypeError):
-            context.set_tlsext_use_srtp(text_type('SRTP_AES128_CM_SHA1_80'))
+            context.set_tlsext_use_srtp(text_type("SRTP_AES128_CM_SHA1_80"))
 
     def test_set_tlsext_use_srtp_invalid_profile(self):
         """
@@ -1557,7 +1619,7 @@ class TestContext(object):
         """
         context = Context(TLSv1_METHOD)
         with pytest.raises(Error):
-            context.set_tlsext_use_srtp(b'SRTP_BOGUS')
+            context.set_tlsext_use_srtp(b"SRTP_BOGUS")
 
     def test_set_tlsext_use_srtp_valid(self):
         """
@@ -1566,7 +1628,7 @@ class TestContext(object):
         It does not return anything.
         """
         context = Context(TLSv1_METHOD)
-        assert context.set_tlsext_use_srtp(b'SRTP_AES128_CM_SHA1_80') is None
+        assert context.set_tlsext_use_srtp(b"SRTP_AES128_CM_SHA1_80") is None
 
 
 class TestServerNameCallback(object):
@@ -1574,11 +1636,13 @@ class TestServerNameCallback(object):
     Tests for `Context.set_tlsext_servername_callback` and its
     interaction with `Connection`.
     """
+
     def test_old_callback_forgotten(self):
         """
         If `Context.set_tlsext_servername_callback` is used to specify
         a new callback, the one it replaces is dereferenced.
         """
+
         def callback(connection):  # pragma: no cover
             pass
 
@@ -1616,6 +1680,7 @@ class TestServerNameCallback(object):
 
         def servername(conn):
             args.append((conn, conn.get_servername()))
+
         context = Context(TLSv1_METHOD)
         context.set_tlsext_servername_callback(servername)
 
@@ -1627,7 +1692,8 @@ class TestServerNameCallback(object):
         # Necessary to actually accept the connection
         context.use_privatekey(load_privatekey(FILETYPE_PEM, server_key_pem))
         context.use_certificate(
-            load_certificate(FILETYPE_PEM, server_cert_pem))
+            load_certificate(FILETYPE_PEM, server_cert_pem)
+        )
 
         # Do a little connection to trigger the logic
         server = Connection(context, None)
@@ -1651,13 +1717,15 @@ class TestServerNameCallback(object):
 
         def servername(conn):
             args.append((conn, conn.get_servername()))
+
         context = Context(TLSv1_METHOD)
         context.set_tlsext_servername_callback(servername)
 
         # Necessary to actually accept the connection
         context.use_privatekey(load_privatekey(FILETYPE_PEM, server_key_pem))
         context.use_certificate(
-            load_certificate(FILETYPE_PEM, server_cert_pem))
+            load_certificate(FILETYPE_PEM, server_cert_pem)
+        )
 
         # Do a little connection to trigger the logic
         server = Connection(context, None)
@@ -1679,6 +1747,7 @@ class TestNextProtoNegotiation(object):
     """
     Test for Next Protocol Negotiation in PyOpenSSL.
     """
+
     def test_npn_success(self):
         """
         Tests that clients and servers that agree on the negotiated next
@@ -1690,11 +1759,11 @@ class TestNextProtoNegotiation(object):
 
         def advertise(conn):
             advertise_args.append((conn,))
-            return [b'http/1.1', b'spdy/2']
+            return [b"http/1.1", b"spdy/2"]
 
         def select(conn, options):
             select_args.append((conn, options))
-            return b'spdy/2'
+            return b"spdy/2"
 
         server_context = Context(TLSv1_METHOD)
         server_context.set_npn_advertise_callback(advertise)
@@ -1704,9 +1773,11 @@ class TestNextProtoNegotiation(object):
 
         # Necessary to actually accept the connection
         server_context.use_privatekey(
-            load_privatekey(FILETYPE_PEM, server_key_pem))
+            load_privatekey(FILETYPE_PEM, server_key_pem)
+        )
         server_context.use_certificate(
-            load_certificate(FILETYPE_PEM, server_cert_pem))
+            load_certificate(FILETYPE_PEM, server_cert_pem)
+        )
 
         # Do a little connection to trigger the logic
         server = Connection(server_context, None)
@@ -1718,10 +1789,10 @@ class TestNextProtoNegotiation(object):
         interact_in_memory(server, client)
 
         assert advertise_args == [(server,)]
-        assert select_args == [(client, [b'http/1.1', b'spdy/2'])]
+        assert select_args == [(client, [b"http/1.1", b"spdy/2"])]
 
-        assert server.get_next_proto_negotiated() == b'spdy/2'
-        assert client.get_next_proto_negotiated() == b'spdy/2'
+        assert server.get_next_proto_negotiated() == b"spdy/2"
+        assert client.get_next_proto_negotiated() == b"spdy/2"
 
     def test_npn_client_fail(self):
         """
@@ -1733,11 +1804,11 @@ class TestNextProtoNegotiation(object):
 
         def advertise(conn):
             advertise_args.append((conn,))
-            return [b'http/1.1', b'spdy/2']
+            return [b"http/1.1", b"spdy/2"]
 
         def select(conn, options):
             select_args.append((conn, options))
-            return b''
+            return b""
 
         server_context = Context(TLSv1_METHOD)
         server_context.set_npn_advertise_callback(advertise)
@@ -1747,9 +1818,11 @@ class TestNextProtoNegotiation(object):
 
         # Necessary to actually accept the connection
         server_context.use_privatekey(
-            load_privatekey(FILETYPE_PEM, server_key_pem))
+            load_privatekey(FILETYPE_PEM, server_key_pem)
+        )
         server_context.use_certificate(
-            load_certificate(FILETYPE_PEM, server_cert_pem))
+            load_certificate(FILETYPE_PEM, server_cert_pem)
+        )
 
         # Do a little connection to trigger the logic
         server = Connection(server_context, None)
@@ -1763,7 +1836,7 @@ class TestNextProtoNegotiation(object):
             interact_in_memory(server, client)
 
         assert advertise_args == [(server,)]
-        assert select_args == [(client, [b'http/1.1', b'spdy/2'])]
+        assert select_args == [(client, [b"http/1.1", b"spdy/2"])]
 
     def test_npn_select_error(self):
         """
@@ -1774,7 +1847,7 @@ class TestNextProtoNegotiation(object):
 
         def advertise(conn):
             advertise_args.append((conn,))
-            return [b'http/1.1', b'spdy/2']
+            return [b"http/1.1", b"spdy/2"]
 
         def select(conn, options):
             raise TypeError
@@ -1787,9 +1860,11 @@ class TestNextProtoNegotiation(object):
 
         # Necessary to actually accept the connection
         server_context.use_privatekey(
-            load_privatekey(FILETYPE_PEM, server_key_pem))
+            load_privatekey(FILETYPE_PEM, server_key_pem)
+        )
         server_context.use_certificate(
-            load_certificate(FILETYPE_PEM, server_cert_pem))
+            load_certificate(FILETYPE_PEM, server_cert_pem)
+        )
 
         # Do a little connection to trigger the logic
         server = Connection(server_context, None)
@@ -1801,7 +1876,9 @@ class TestNextProtoNegotiation(object):
         # If the callback throws an exception it should be raised here.
         with pytest.raises(TypeError):
             interact_in_memory(server, client)
-        assert advertise_args == [(server,), ]
+        assert advertise_args == [
+            (server,),
+        ]
 
     def test_npn_advertise_error(self):
         """
@@ -1818,7 +1895,7 @@ class TestNextProtoNegotiation(object):
             Assert later that no args are actually appended.
             """
             select_args.append((conn, options))
-            return b''
+            return b""
 
         server_context = Context(TLSv1_METHOD)
         server_context.set_npn_advertise_callback(advertise)
@@ -1828,9 +1905,11 @@ class TestNextProtoNegotiation(object):
 
         # Necessary to actually accept the connection
         server_context.use_privatekey(
-            load_privatekey(FILETYPE_PEM, server_key_pem))
+            load_privatekey(FILETYPE_PEM, server_key_pem)
+        )
         server_context.use_certificate(
-            load_certificate(FILETYPE_PEM, server_cert_pem))
+            load_certificate(FILETYPE_PEM, server_cert_pem)
+        )
 
         # Do a little connection to trigger the logic
         server = Connection(server_context, None)
@@ -1849,6 +1928,7 @@ class TestApplicationLayerProtoNegotiation(object):
     """
     Tests for ALPN in PyOpenSSL.
     """
+
     def test_alpn_success(self):
         """
         Clients and servers that agree on the negotiated ALPN protocol can
@@ -1859,19 +1939,21 @@ class TestApplicationLayerProtoNegotiation(object):
 
         def select(conn, options):
             select_args.append((conn, options))
-            return b'spdy/2'
+            return b"spdy/2"
 
         client_context = Context(TLSv1_METHOD)
-        client_context.set_alpn_protos([b'http/1.1', b'spdy/2'])
+        client_context.set_alpn_protos([b"http/1.1", b"spdy/2"])
 
         server_context = Context(TLSv1_METHOD)
         server_context.set_alpn_select_callback(select)
 
         # Necessary to actually accept the connection
         server_context.use_privatekey(
-            load_privatekey(FILETYPE_PEM, server_key_pem))
+            load_privatekey(FILETYPE_PEM, server_key_pem)
+        )
         server_context.use_certificate(
-            load_certificate(FILETYPE_PEM, server_cert_pem))
+            load_certificate(FILETYPE_PEM, server_cert_pem)
+        )
 
         # Do a little connection to trigger the logic
         server = Connection(server_context, None)
@@ -1882,10 +1964,10 @@ class TestApplicationLayerProtoNegotiation(object):
 
         interact_in_memory(server, client)
 
-        assert select_args == [(server, [b'http/1.1', b'spdy/2'])]
+        assert select_args == [(server, [b"http/1.1", b"spdy/2"])]
 
-        assert server.get_alpn_proto_negotiated() == b'spdy/2'
-        assert client.get_alpn_proto_negotiated() == b'spdy/2'
+        assert server.get_alpn_proto_negotiated() == b"spdy/2"
+        assert client.get_alpn_proto_negotiated() == b"spdy/2"
 
     def test_alpn_set_on_connection(self):
         """
@@ -1896,7 +1978,7 @@ class TestApplicationLayerProtoNegotiation(object):
 
         def select(conn, options):
             select_args.append((conn, options))
-            return b'spdy/2'
+            return b"spdy/2"
 
         # Setup the client context but don't set any ALPN protocols.
         client_context = Context(TLSv1_METHOD)
@@ -1906,9 +1988,11 @@ class TestApplicationLayerProtoNegotiation(object):
 
         # Necessary to actually accept the connection
         server_context.use_privatekey(
-            load_privatekey(FILETYPE_PEM, server_key_pem))
+            load_privatekey(FILETYPE_PEM, server_key_pem)
+        )
         server_context.use_certificate(
-            load_certificate(FILETYPE_PEM, server_cert_pem))
+            load_certificate(FILETYPE_PEM, server_cert_pem)
+        )
 
         # Do a little connection to trigger the logic
         server = Connection(server_context, None)
@@ -1916,15 +2000,15 @@ class TestApplicationLayerProtoNegotiation(object):
 
         # Set the ALPN protocols on the client connection.
         client = Connection(client_context, None)
-        client.set_alpn_protos([b'http/1.1', b'spdy/2'])
+        client.set_alpn_protos([b"http/1.1", b"spdy/2"])
         client.set_connect_state()
 
         interact_in_memory(server, client)
 
-        assert select_args == [(server, [b'http/1.1', b'spdy/2'])]
+        assert select_args == [(server, [b"http/1.1", b"spdy/2"])]
 
-        assert server.get_alpn_proto_negotiated() == b'spdy/2'
-        assert client.get_alpn_proto_negotiated() == b'spdy/2'
+        assert server.get_alpn_proto_negotiated() == b"spdy/2"
+        assert client.get_alpn_proto_negotiated() == b"spdy/2"
 
     def test_alpn_server_fail(self):
         """
@@ -1935,19 +2019,21 @@ class TestApplicationLayerProtoNegotiation(object):
 
         def select(conn, options):
             select_args.append((conn, options))
-            return b''
+            return b""
 
         client_context = Context(TLSv1_METHOD)
-        client_context.set_alpn_protos([b'http/1.1', b'spdy/2'])
+        client_context.set_alpn_protos([b"http/1.1", b"spdy/2"])
 
         server_context = Context(TLSv1_METHOD)
         server_context.set_alpn_select_callback(select)
 
         # Necessary to actually accept the connection
         server_context.use_privatekey(
-            load_privatekey(FILETYPE_PEM, server_key_pem))
+            load_privatekey(FILETYPE_PEM, server_key_pem)
+        )
         server_context.use_certificate(
-            load_certificate(FILETYPE_PEM, server_cert_pem))
+            load_certificate(FILETYPE_PEM, server_cert_pem)
+        )
 
         # Do a little connection to trigger the logic
         server = Connection(server_context, None)
@@ -1960,7 +2046,7 @@ class TestApplicationLayerProtoNegotiation(object):
         with pytest.raises(Error):
             interact_in_memory(server, client)
 
-        assert select_args == [(server, [b'http/1.1', b'spdy/2'])]
+        assert select_args == [(server, [b"http/1.1", b"spdy/2"])]
 
     def test_alpn_no_server_overlap(self):
         """
@@ -1975,16 +2061,18 @@ class TestApplicationLayerProtoNegotiation(object):
             return NO_OVERLAPPING_PROTOCOLS
 
         client_context = Context(SSLv23_METHOD)
-        client_context.set_alpn_protos([b'http/1.1', b'spdy/2'])
+        client_context.set_alpn_protos([b"http/1.1", b"spdy/2"])
 
         server_context = Context(SSLv23_METHOD)
         server_context.set_alpn_select_callback(refusal)
 
         # Necessary to actually accept the connection
         server_context.use_privatekey(
-            load_privatekey(FILETYPE_PEM, server_key_pem))
+            load_privatekey(FILETYPE_PEM, server_key_pem)
+        )
         server_context.use_certificate(
-            load_certificate(FILETYPE_PEM, server_cert_pem))
+            load_certificate(FILETYPE_PEM, server_cert_pem)
+        )
 
         # Do a little connection to trigger the logic
         server = Connection(server_context, None)
@@ -1996,9 +2084,9 @@ class TestApplicationLayerProtoNegotiation(object):
         # Do the dance.
         interact_in_memory(server, client)
 
-        assert refusal_args == [(server, [b'http/1.1', b'spdy/2'])]
+        assert refusal_args == [(server, [b"http/1.1", b"spdy/2"])]
 
-        assert client.get_alpn_proto_negotiated() == b''
+        assert client.get_alpn_proto_negotiated() == b""
 
     def test_alpn_select_cb_returns_invalid_value(self):
         """
@@ -2013,16 +2101,18 @@ class TestApplicationLayerProtoNegotiation(object):
             return u"can't return unicode"
 
         client_context = Context(SSLv23_METHOD)
-        client_context.set_alpn_protos([b'http/1.1', b'spdy/2'])
+        client_context.set_alpn_protos([b"http/1.1", b"spdy/2"])
 
         server_context = Context(SSLv23_METHOD)
         server_context.set_alpn_select_callback(invalid_cb)
 
         # Necessary to actually accept the connection
         server_context.use_privatekey(
-            load_privatekey(FILETYPE_PEM, server_key_pem))
+            load_privatekey(FILETYPE_PEM, server_key_pem)
+        )
         server_context.use_certificate(
-            load_certificate(FILETYPE_PEM, server_cert_pem))
+            load_certificate(FILETYPE_PEM, server_cert_pem)
+        )
 
         # Do a little connection to trigger the logic
         server = Connection(server_context, None)
@@ -2035,9 +2125,9 @@ class TestApplicationLayerProtoNegotiation(object):
         with pytest.raises(TypeError):
             interact_in_memory(server, client)
 
-        assert invalid_cb_args == [(server, [b'http/1.1', b'spdy/2'])]
+        assert invalid_cb_args == [(server, [b"http/1.1", b"spdy/2"])]
 
-        assert client.get_alpn_proto_negotiated() == b''
+        assert client.get_alpn_proto_negotiated() == b""
 
     def test_alpn_no_server(self):
         """
@@ -2045,15 +2135,17 @@ class TestApplicationLayerProtoNegotiation(object):
         because the server doesn't offer ALPN, no protocol is negotiated.
         """
         client_context = Context(TLSv1_METHOD)
-        client_context.set_alpn_protos([b'http/1.1', b'spdy/2'])
+        client_context.set_alpn_protos([b"http/1.1", b"spdy/2"])
 
         server_context = Context(TLSv1_METHOD)
 
         # Necessary to actually accept the connection
         server_context.use_privatekey(
-            load_privatekey(FILETYPE_PEM, server_key_pem))
+            load_privatekey(FILETYPE_PEM, server_key_pem)
+        )
         server_context.use_certificate(
-            load_certificate(FILETYPE_PEM, server_cert_pem))
+            load_certificate(FILETYPE_PEM, server_cert_pem)
+        )
 
         # Do a little connection to trigger the logic
         server = Connection(server_context, None)
@@ -2065,7 +2157,7 @@ class TestApplicationLayerProtoNegotiation(object):
         # Do the dance.
         interact_in_memory(server, client)
 
-        assert client.get_alpn_proto_negotiated() == b''
+        assert client.get_alpn_proto_negotiated() == b""
 
     def test_alpn_callback_exception(self):
         """
@@ -2078,16 +2170,18 @@ class TestApplicationLayerProtoNegotiation(object):
             raise TypeError()
 
         client_context = Context(TLSv1_METHOD)
-        client_context.set_alpn_protos([b'http/1.1', b'spdy/2'])
+        client_context.set_alpn_protos([b"http/1.1", b"spdy/2"])
 
         server_context = Context(TLSv1_METHOD)
         server_context.set_alpn_select_callback(select)
 
         # Necessary to actually accept the connection
         server_context.use_privatekey(
-            load_privatekey(FILETYPE_PEM, server_key_pem))
+            load_privatekey(FILETYPE_PEM, server_key_pem)
+        )
         server_context.use_certificate(
-            load_certificate(FILETYPE_PEM, server_cert_pem))
+            load_certificate(FILETYPE_PEM, server_cert_pem)
+        )
 
         # Do a little connection to trigger the logic
         server = Connection(server_context, None)
@@ -2098,13 +2192,14 @@ class TestApplicationLayerProtoNegotiation(object):
 
         with pytest.raises(TypeError):
             interact_in_memory(server, client)
-        assert select_args == [(server, [b'http/1.1', b'spdy/2'])]
+        assert select_args == [(server, [b"http/1.1", b"spdy/2"])]
 
 
 class TestSession(object):
     """
     Unit tests for :py:obj:`OpenSSL.SSL.Session`.
     """
+
     def test_construction(self):
         """
         :py:class:`Session` can be constructed with no arguments, creating
@@ -2118,6 +2213,7 @@ class TestConnection(object):
     """
     Unit tests for `OpenSSL.SSL.Connection`.
     """
+
     # XXX get_peer_certificate -> None
     # XXX sock_shutdown
     # XXX master_key -> TypeError
@@ -2137,9 +2233,9 @@ class TestConnection(object):
         `Connection` can be used to create instances of that type.
         """
         ctx = Context(TLSv1_METHOD)
-        assert is_consistent_type(Connection, 'Connection', ctx, None)
+        assert is_consistent_type(Connection, "Connection", ctx, None)
 
-    @pytest.mark.parametrize('bad_context', [object(), 'context', None, 1])
+    @pytest.mark.parametrize("bad_context", [object(), "context", None, 1])
     def test_wrong_args(self, bad_context):
         """
         `Connection.__init__` raises `TypeError` if called with a non-`Context`
@@ -2148,7 +2244,7 @@ class TestConnection(object):
         with pytest.raises(TypeError):
             Connection(bad_context)
 
-    @pytest.mark.parametrize('bad_bio', [object(), None, 1, [1, 2, 3]])
+    @pytest.mark.parametrize("bad_bio", [object(), None, 1, [1, 2, 3]])
     def test_bio_write_wrong_args(self, bad_bio):
         """
         `Connection.bio_write` raises `TypeError` if called with a non-bytes
@@ -2166,10 +2262,10 @@ class TestConnection(object):
         """
         context = Context(TLSv1_METHOD)
         connection = Connection(context, None)
-        connection.bio_write(b'xy')
-        connection.bio_write(bytearray(b'za'))
+        connection.bio_write(b"xy")
+        connection.bio_write(bytearray(b"za"))
         with pytest.warns(DeprecationWarning):
-            connection.bio_write(u'deprecated')
+            connection.bio_write(u"deprecated")
 
     def test_get_context(self):
         """
@@ -2241,10 +2337,10 @@ class TestConnection(object):
         passed.
         """
         server, client = loopback()
-        server.send(b'xy')
-        assert client.recv(2, MSG_PEEK) == b'xy'
-        assert client.recv(2, MSG_PEEK) == b'xy'
-        assert client.recv(2) == b'xy'
+        server.send(b"xy")
+        assert client.recv(2, MSG_PEEK) == b"xy"
+        assert client.recv(2, MSG_PEEK) == b"xy"
+        assert client.recv(2) == b"xy"
 
     def test_connect_wrong_args(self):
         """
@@ -2276,7 +2372,7 @@ class TestConnection(object):
         `Connection.connect` establishes a connection to the specified address.
         """
         port = socket_any_family()
-        port.bind(('', 0))
+        port.bind(("", 0))
         port.listen(3)
 
         clientSSL = Connection(Context(TLSv1_METHOD), socket(port.family))
@@ -2285,7 +2381,7 @@ class TestConnection(object):
 
     @pytest.mark.skipif(
         platform == "darwin",
-        reason="connect_ex sometimes causes a kernel panic on OS X 10.6.4"
+        reason="connect_ex sometimes causes a kernel panic on OS X 10.6.4",
     )
     def test_connect_ex(self):
         """
@@ -2293,7 +2389,7 @@ class TestConnection(object):
         errno instead of raising an exception.
         """
         port = socket_any_family()
-        port.bind(('', 0))
+        port.bind(("", 0))
         port.listen(3)
 
         clientSSL = Connection(Context(TLSv1_METHOD), socket(port.family))
@@ -2313,7 +2409,7 @@ class TestConnection(object):
         ctx.use_certificate(load_certificate(FILETYPE_PEM, server_cert_pem))
         port = socket_any_family()
         portSSL = Connection(ctx, port)
-        portSSL.bind(('', 0))
+        portSSL.bind(("", 0))
         portSSL.listen(3)
 
         clientSSL = Connection(Context(TLSv1_METHOD), socket(port.family))
@@ -2375,9 +2471,11 @@ class TestConnection(object):
         server_ctx = Context(TLSv1_METHOD)
         client_ctx = Context(TLSv1_METHOD)
         server_ctx.use_privatekey(
-            load_privatekey(FILETYPE_PEM, server_key_pem))
+            load_privatekey(FILETYPE_PEM, server_key_pem)
+        )
         server_ctx.use_certificate(
-            load_certificate(FILETYPE_PEM, server_cert_pem))
+            load_certificate(FILETYPE_PEM, server_cert_pem)
+        )
         server = Connection(server_ctx, None)
         client = Connection(client_ctx, None)
         handshake_in_memory(client, server)
@@ -2407,10 +2505,12 @@ class TestConnection(object):
         client = loopback_client_factory(client)
 
         assert server.get_state_string() in [
-            b"before/accept initialization", b"before SSL initialization"
+            b"before/accept initialization",
+            b"before SSL initialization",
         ]
         assert client.get_state_string() in [
-            b"before/connect initialization", b"before SSL initialization"
+            b"before/connect initialization",
+            b"before SSL initialization",
         ]
 
     def test_app_data(self):
@@ -2565,17 +2665,17 @@ class TestConnection(object):
             server.set_accept_state()
             return server
 
-        originalServer, originalClient = loopback(
-            server_factory=makeServer)
+        originalServer, originalClient = loopback(server_factory=makeServer)
         originalSession = originalClient.get_session()
 
         def makeClient(socket):
             client = loopback_client_factory(socket)
             client.set_session(originalSession)
             return client
+
         resumedServer, resumedClient = loopback(
-            server_factory=makeServer,
-            client_factory=makeClient)
+            server_factory=makeServer, client_factory=makeClient
+        )
 
         # This is a proxy: in general, we have no access to any unique
         # identifier for the session (new enough versions of OpenSSL expose
@@ -2621,7 +2721,8 @@ class TestConnection(object):
             return client
 
         originalServer, originalClient = loopback(
-            server_factory=makeServer, client_factory=makeOriginalClient)
+            server_factory=makeServer, client_factory=makeOriginalClient
+        )
         originalSession = originalClient.get_session()
 
         def makeClient(socket):
@@ -2657,7 +2758,8 @@ class TestConnection(object):
                 raise
         else:
             pytest.fail(
-                "Failed to fill socket buffer, cannot test BIO want write")
+                "Failed to fill socket buffer, cannot test BIO want write"
+            )
 
         ctx = Context(TLSv1_METHOD)
         conn = Connection(ctx, client_socket)
@@ -2736,8 +2838,10 @@ class TestConnection(object):
         name of the currently used cipher.
         """
         server, client = loopback()
-        server_cipher_name, client_cipher_name = \
-            server.get_cipher_name(), client.get_cipher_name()
+        server_cipher_name, client_cipher_name = (
+            server.get_cipher_name(),
+            client.get_cipher_name(),
+        )
 
         assert isinstance(server_cipher_name, text_type)
         assert isinstance(client_cipher_name, text_type)
@@ -2759,8 +2863,10 @@ class TestConnection(object):
         the protocol name of the currently used cipher.
         """
         server, client = loopback()
-        server_cipher_version, client_cipher_version = \
-            server.get_cipher_version(), client.get_cipher_version()
+        server_cipher_version, client_cipher_version = (
+            server.get_cipher_version(),
+            client.get_cipher_version(),
+        )
 
         assert isinstance(server_cipher_version, text_type)
         assert isinstance(client_cipher_version, text_type)
@@ -2782,8 +2888,10 @@ class TestConnection(object):
         of the currently used cipher.
         """
         server, client = loopback()
-        server_cipher_bits, client_cipher_bits = \
-            server.get_cipher_bits(), client.get_cipher_bits()
+        server_cipher_bits, client_cipher_bits = (
+            server.get_cipher_bits(),
+            client.get_cipher_bits(),
+        )
 
         assert isinstance(server_cipher_bits, int)
         assert isinstance(client_cipher_bits, int)
@@ -2828,7 +2936,7 @@ class TestConnection(object):
         with pytest.raises(WantReadError):
             conn.bio_read(1024)
 
-    @pytest.mark.parametrize('bufsize', [1.0, None, object(), 'bufsize'])
+    @pytest.mark.parametrize("bufsize", [1.0, None, object(), "bufsize"])
     def test_bio_read_wrong_args(self, bufsize):
         """
         `Connection.bio_read` raises `TypeError` if passed a non-integer
@@ -2859,6 +2967,7 @@ class TestConnectionGetCipherList(object):
     """
     Tests for `Connection.get_cipher_list`.
     """
+
     def test_result(self):
         """
         `Connection.get_cipher_list` returns a list of `bytes` giving the
@@ -2875,14 +2984,16 @@ class VeryLarge(bytes):
     """
     Mock object so that we don't have to allocate 2**31 bytes
     """
+
     def __len__(self):
-        return 2**31
+        return 2 ** 31
 
 
 class TestConnectionSend(object):
     """
     Tests for `Connection.send`.
     """
+
     def test_wrong_args(self):
         """
         When called with arguments other than string argument for its first
@@ -2900,9 +3011,9 @@ class TestConnectionSend(object):
         and returns the number of bytes sent.
         """
         server, client = loopback()
-        count = server.send(b'xy')
+        count = server.send(b"xy")
         assert count == 2
-        assert client.recv(2) == b'xy'
+        assert client.recv(2) == b"xy"
 
     def test_text(self):
         """
@@ -2913,12 +3024,11 @@ class TestConnectionSend(object):
         with pytest.warns(DeprecationWarning) as w:
             simplefilter("always")
             count = server.send(b"xy".decode("ascii"))
-            assert (
-                "{0} for buf is no longer accepted, use bytes".format(
-                    WARNING_TYPE_EXPECTED
-                ) == str(w[-1].message))
+            assert "{0} for buf is no longer accepted, use bytes".format(
+                WARNING_TYPE_EXPECTED
+            ) == str(w[-1].message)
         assert count == 2
-        assert client.recv(2) == b'xy'
+        assert client.recv(2) == b"xy"
 
     def test_short_memoryview(self):
         """
@@ -2927,9 +3037,9 @@ class TestConnectionSend(object):
         of bytes sent.
         """
         server, client = loopback()
-        count = server.send(memoryview(b'xy'))
+        count = server.send(memoryview(b"xy"))
         assert count == 2
-        assert client.recv(2) == b'xy'
+        assert client.recv(2) == b"xy"
 
     def test_short_bytearray(self):
         """
@@ -2937,9 +3047,9 @@ class TestConnectionSend(object):
         it and returns the number of bytes sent.
         """
         server, client = loopback()
-        count = server.send(bytearray(b'xy'))
+        count = server.send(bytearray(b"xy"))
         assert count == 2
-        assert client.recv(2) == b'xy'
+        assert client.recv(2) == b"xy"
 
     @skip_if_py3
     def test_short_buffer(self):
@@ -2949,13 +3059,13 @@ class TestConnectionSend(object):
         of bytes sent.
         """
         server, client = loopback()
-        count = server.send(buffer(b'xy'))
+        count = server.send(buffer(b"xy"))  # noqa: F821
         assert count == 2
-        assert client.recv(2) == b'xy'
+        assert client.recv(2) == b"xy"
 
     @pytest.mark.skipif(
-        sys.maxsize < 2**31,
-        reason="sys.maxsize < 2**31 - test requires 64 bit"
+        sys.maxsize < 2 ** 31,
+        reason="sys.maxsize < 2**31 - test requires 64 bit",
     )
     def test_buf_too_large(self):
         """
@@ -2981,6 +3091,7 @@ class TestConnectionRecvInto(object):
     """
     Tests for `Connection.recv_into`.
     """
+
     def _no_length_test(self, factory):
         """
         Assert that when the given buffer is passed to `Connection.recv_into`,
@@ -2990,10 +3101,10 @@ class TestConnectionRecvInto(object):
         output_buffer = factory(5)
 
         server, client = loopback()
-        server.send(b'xy')
+        server.send(b"xy")
 
         assert client.recv_into(output_buffer) == 2
-        assert output_buffer == bytearray(b'xy\x00\x00\x00')
+        assert output_buffer == bytearray(b"xy\x00\x00\x00")
 
     def test_bytearray_no_length(self):
         """
@@ -3011,10 +3122,10 @@ class TestConnectionRecvInto(object):
         output_buffer = factory(10)
 
         server, client = loopback()
-        server.send(b'abcdefghij')
+        server.send(b"abcdefghij")
 
         assert client.recv_into(output_buffer, 5) == 5
-        assert output_buffer == bytearray(b'abcde\x00\x00\x00\x00\x00')
+        assert output_buffer == bytearray(b"abcde\x00\x00\x00\x00\x00")
 
     def test_bytearray_respects_length(self):
         """
@@ -3033,12 +3144,12 @@ class TestConnectionRecvInto(object):
         output_buffer = factory(5)
 
         server, client = loopback()
-        server.send(b'abcdefghij')
+        server.send(b"abcdefghij")
 
         assert client.recv_into(output_buffer) == 5
-        assert output_buffer == bytearray(b'abcde')
+        assert output_buffer == bytearray(b"abcde")
         rest = client.recv(5)
-        assert b'fghij' == rest
+        assert b"fghij" == rest
 
     def test_bytearray_doesnt_overfill(self):
         """
@@ -3059,12 +3170,12 @@ class TestConnectionRecvInto(object):
 
     def test_peek(self):
         server, client = loopback()
-        server.send(b'xy')
+        server.send(b"xy")
 
         for _ in range(2):
             output_buffer = bytearray(5)
             assert client.recv_into(output_buffer, flags=MSG_PEEK) == 2
-            assert output_buffer == bytearray(b'xy\x00\x00\x00')
+            assert output_buffer == bytearray(b"xy\x00\x00\x00")
 
     def test_memoryview_no_length(self):
         """
@@ -3103,6 +3214,7 @@ class TestConnectionSendall(object):
     """
     Tests for `Connection.sendall`.
     """
+
     def test_wrong_args(self):
         """
         When called with arguments other than a string argument for its first
@@ -3120,8 +3232,8 @@ class TestConnectionSendall(object):
         passed to it.
         """
         server, client = loopback()
-        server.sendall(b'x')
-        assert client.recv(1) == b'x'
+        server.sendall(b"x")
+        assert client.recv(1) == b"x"
 
     def test_text(self):
         """
@@ -3132,10 +3244,9 @@ class TestConnectionSendall(object):
         with pytest.warns(DeprecationWarning) as w:
             simplefilter("always")
             server.sendall(b"x".decode("ascii"))
-            assert (
-                "{0} for buf is no longer accepted, use bytes".format(
-                    WARNING_TYPE_EXPECTED
-                ) == str(w[-1].message))
+            assert "{0} for buf is no longer accepted, use bytes".format(
+                WARNING_TYPE_EXPECTED
+            ) == str(w[-1].message)
         assert client.recv(1) == b"x"
 
     def test_short_memoryview(self):
@@ -3144,8 +3255,8 @@ class TestConnectionSendall(object):
         `Connection.sendall` transmits all of them.
         """
         server, client = loopback()
-        server.sendall(memoryview(b'x'))
-        assert client.recv(1) == b'x'
+        server.sendall(memoryview(b"x"))
+        assert client.recv(1) == b"x"
 
     @skip_if_py3
     def test_short_buffers(self):
@@ -3154,9 +3265,9 @@ class TestConnectionSendall(object):
         `Connection.sendall` transmits all of them.
         """
         server, client = loopback()
-        count = server.sendall(buffer(b'xy'))
+        count = server.sendall(buffer(b"xy"))  # noqa: F821
         assert count == 2
-        assert client.recv(2) == b'xy'
+        assert client.recv(2) == b"xy"
 
     def test_long(self):
         """
@@ -3167,7 +3278,7 @@ class TestConnectionSendall(object):
         # Should be enough, underlying SSL_write should only do 16k at a time.
         # On Windows, after 32k of bytes the write will block (forever
         # - because no one is yet reading).
-        message = b'x' * (1024 * 32 - 1) + b'y'
+        message = b"x" * (1024 * 32 - 1) + b"y"
         server.sendall(message)
         accum = []
         received = 0
@@ -3175,7 +3286,7 @@ class TestConnectionSendall(object):
             data = client.recv(1024)
             accum.append(data)
             received += len(data)
-        assert message == b''.join(accum)
+        assert message == b"".join(accum)
 
     def test_closed(self):
         """
@@ -3196,6 +3307,7 @@ class TestConnectionRenegotiate(object):
     """
     Tests for SSL renegotiation APIs.
     """
+
     def test_total_renegotiations(self):
         """
         `Connection.total_renegotiations` returns `0` before any renegotiations
@@ -3239,12 +3351,13 @@ class TestError(object):
     """
     Unit tests for `OpenSSL.SSL.Error`.
     """
+
     def test_type(self):
         """
         `Error` is an exception type.
         """
         assert issubclass(Error, Exception)
-        assert Error.__name__ == 'Error'
+        assert Error.__name__ == "Error"
 
 
 class TestConstants(object):
@@ -3255,9 +3368,10 @@ class TestConstants(object):
     OpenSSL APIs.  The only assertions it seems can be made about them is
     their values.
     """
+
     @pytest.mark.skipif(
         OP_NO_QUERY_MTU is None,
-        reason="OP_NO_QUERY_MTU unavailable - OpenSSL version may be too old"
+        reason="OP_NO_QUERY_MTU unavailable - OpenSSL version may be too old",
     )
     def test_op_no_query_mtu(self):
         """
@@ -3269,7 +3383,7 @@ class TestConstants(object):
     @pytest.mark.skipif(
         OP_COOKIE_EXCHANGE is None,
         reason="OP_COOKIE_EXCHANGE unavailable - "
-        "OpenSSL version may be too old"
+        "OpenSSL version may be too old",
     )
     def test_op_cookie_exchange(self):
         """
@@ -3280,7 +3394,7 @@ class TestConstants(object):
 
     @pytest.mark.skipif(
         OP_NO_TICKET is None,
-        reason="OP_NO_TICKET unavailable - OpenSSL version may be too old"
+        reason="OP_NO_TICKET unavailable - OpenSSL version may be too old",
     )
     def test_op_no_ticket(self):
         """
@@ -3291,7 +3405,9 @@ class TestConstants(object):
 
     @pytest.mark.skipif(
         OP_NO_COMPRESSION is None,
-        reason="OP_NO_COMPRESSION unavailable - OpenSSL version may be too old"
+        reason=(
+            "OP_NO_COMPRESSION unavailable - OpenSSL version may be too old"
+        ),
     )
     def test_op_no_compression(self):
         """
@@ -3365,6 +3481,7 @@ class TestMemoryBIO(object):
     """
     Tests for `OpenSSL.SSL.Connection` using a memory BIO.
     """
+
     def _server(self, sock):
         """
         Create a new server-side SSL `Connection` object wrapped around `sock`.
@@ -3375,13 +3492,15 @@ class TestMemoryBIO(object):
         server_ctx.set_options(OP_NO_SSLv2 | OP_NO_SSLv3 | OP_SINGLE_DH_USE)
         server_ctx.set_verify(
             VERIFY_PEER | VERIFY_FAIL_IF_NO_PEER_CERT | VERIFY_CLIENT_ONCE,
-            verify_cb
+            verify_cb,
         )
         server_store = server_ctx.get_cert_store()
         server_ctx.use_privatekey(
-            load_privatekey(FILETYPE_PEM, server_key_pem))
+            load_privatekey(FILETYPE_PEM, server_key_pem)
+        )
         server_ctx.use_certificate(
-            load_certificate(FILETYPE_PEM, server_cert_pem))
+            load_certificate(FILETYPE_PEM, server_cert_pem)
+        )
         server_ctx.check_privatekey()
         server_store.add_cert(load_certificate(FILETYPE_PEM, root_cert_pem))
         # Here the Connection is actually created.  If None is passed as the
@@ -3400,13 +3519,15 @@ class TestMemoryBIO(object):
         client_ctx.set_options(OP_NO_SSLv2 | OP_NO_SSLv3 | OP_SINGLE_DH_USE)
         client_ctx.set_verify(
             VERIFY_PEER | VERIFY_FAIL_IF_NO_PEER_CERT | VERIFY_CLIENT_ONCE,
-            verify_cb
+            verify_cb,
         )
         client_store = client_ctx.get_cert_store()
         client_ctx.use_privatekey(
-            load_privatekey(FILETYPE_PEM, client_key_pem))
+            load_privatekey(FILETYPE_PEM, client_key_pem)
+        )
         client_ctx.use_certificate(
-            load_certificate(FILETYPE_PEM, client_cert_pem))
+            load_certificate(FILETYPE_PEM, client_cert_pem)
+        )
         client_ctx.check_privatekey()
         client_store.add_cert(load_certificate(FILETYPE_PEM, root_cert_pem))
         client_conn = Connection(client_ctx, sock)
@@ -3443,39 +3564,41 @@ class TestMemoryBIO(object):
         assert client_conn.client_random() != client_conn.server_random()
 
         # Export key material for other uses.
-        cekm = client_conn.export_keying_material(b'LABEL', 32)
-        sekm = server_conn.export_keying_material(b'LABEL', 32)
+        cekm = client_conn.export_keying_material(b"LABEL", 32)
+        sekm = server_conn.export_keying_material(b"LABEL", 32)
         assert cekm is not None
         assert sekm is not None
         assert cekm == sekm
         assert len(sekm) == 32
 
         # Export key material for other uses with additional context.
-        cekmc = client_conn.export_keying_material(b'LABEL', 32, b'CONTEXT')
-        sekmc = server_conn.export_keying_material(b'LABEL', 32, b'CONTEXT')
+        cekmc = client_conn.export_keying_material(b"LABEL", 32, b"CONTEXT")
+        sekmc = server_conn.export_keying_material(b"LABEL", 32, b"CONTEXT")
         assert cekmc is not None
         assert sekmc is not None
         assert cekmc == sekmc
         assert cekmc != cekm
         assert sekmc != sekm
         # Export with alternate label
-        cekmt = client_conn.export_keying_material(b'test', 32, b'CONTEXT')
-        sekmt = server_conn.export_keying_material(b'test', 32, b'CONTEXT')
+        cekmt = client_conn.export_keying_material(b"test", 32, b"CONTEXT")
+        sekmt = server_conn.export_keying_material(b"test", 32, b"CONTEXT")
         assert cekmc != cekmt
         assert sekmc != sekmt
 
         # Here are the bytes we'll try to send.
-        important_message = b'One if by land, two if by sea.'
+        important_message = b"One if by land, two if by sea."
 
         server_conn.write(important_message)
-        assert (
-            interact_in_memory(client_conn, server_conn) ==
-            (client_conn, important_message))
+        assert interact_in_memory(client_conn, server_conn) == (
+            client_conn,
+            important_message,
+        )
 
         client_conn.write(important_message[::-1])
-        assert (
-            interact_in_memory(client_conn, server_conn) ==
-            (server_conn, important_message[::-1]))
+        assert interact_in_memory(client_conn, server_conn) == (
+            server_conn,
+            important_message[::-1],
+        )
 
     def test_socket_connect(self):
         """
@@ -3608,9 +3731,11 @@ class TestMemoryBIO(object):
         client sides, `Connection.get_client_ca_list` returns an empty list
         after the connection is set up.
         """
+
         def no_ca(ctx):
             ctx.set_client_ca_list([])
             return []
+
         self._check_client_ca_list(no_ca)
 
     def test_set_one_ca_list(self):
@@ -3627,6 +3752,7 @@ class TestMemoryBIO(object):
         def single_ca(ctx):
             ctx.set_client_ca_list([cadesc])
             return [cadesc]
+
         self._check_client_ca_list(single_ca)
 
     def test_set_multiple_ca_list(self):
@@ -3647,6 +3773,7 @@ class TestMemoryBIO(object):
             L = [sedesc, cldesc]
             ctx.set_client_ca_list(L)
             return L
+
         self._check_client_ca_list(multiple_ca)
 
     def test_reset_ca_list(self):
@@ -3667,6 +3794,7 @@ class TestMemoryBIO(object):
             ctx.set_client_ca_list([sedesc, cldesc])
             ctx.set_client_ca_list([cadesc])
             return [cadesc]
+
         self._check_client_ca_list(changed_ca)
 
     def test_mutated_ca_list(self):
@@ -3686,6 +3814,7 @@ class TestMemoryBIO(object):
             ctx.set_client_ca_list([cadesc])
             L.append(sedesc)
             return [cadesc]
+
         self._check_client_ca_list(mutated_ca)
 
     def test_add_client_ca_wrong_args(self):
@@ -3708,6 +3837,7 @@ class TestMemoryBIO(object):
         def single_ca(ctx):
             ctx.add_client_ca(cacert)
             return [cadesc]
+
         self._check_client_ca_list(single_ca)
 
     def test_multiple_add_client_ca(self):
@@ -3725,6 +3855,7 @@ class TestMemoryBIO(object):
             ctx.add_client_ca(cacert)
             ctx.add_client_ca(secert)
             return [cadesc, sedesc]
+
         self._check_client_ca_list(multiple_ca)
 
     def test_set_and_add_client_ca(self):
@@ -3745,6 +3876,7 @@ class TestMemoryBIO(object):
             ctx.set_client_ca_list([cadesc, sedesc])
             ctx.add_client_ca(clcert)
             return [cadesc, sedesc, cldesc]
+
         self._check_client_ca_list(mixed_set_add_ca)
 
     def test_set_after_add_client_ca(self):
@@ -3765,6 +3897,7 @@ class TestMemoryBIO(object):
             ctx.set_client_ca_list([cadesc])
             ctx.add_client_ca(secert)
             return [cadesc, sedesc]
+
         self._check_client_ca_list(set_replaces_add_ca)
 
 
@@ -3772,6 +3905,7 @@ class TestInfoConstants(object):
     """
     Tests for assorted constants exposed for use in info callbacks.
     """
+
     def test_integers(self):
         """
         All of the info constants are integers.
@@ -3781,17 +3915,31 @@ class TestInfoConstants(object):
         info callback matches up with the constant exposed by OpenSSL.SSL.
         """
         for const in [
-            SSL_ST_CONNECT, SSL_ST_ACCEPT, SSL_ST_MASK,
-            SSL_CB_LOOP, SSL_CB_EXIT, SSL_CB_READ, SSL_CB_WRITE, SSL_CB_ALERT,
-            SSL_CB_READ_ALERT, SSL_CB_WRITE_ALERT, SSL_CB_ACCEPT_LOOP,
-            SSL_CB_ACCEPT_EXIT, SSL_CB_CONNECT_LOOP, SSL_CB_CONNECT_EXIT,
-            SSL_CB_HANDSHAKE_START, SSL_CB_HANDSHAKE_DONE
+            SSL_ST_CONNECT,
+            SSL_ST_ACCEPT,
+            SSL_ST_MASK,
+            SSL_CB_LOOP,
+            SSL_CB_EXIT,
+            SSL_CB_READ,
+            SSL_CB_WRITE,
+            SSL_CB_ALERT,
+            SSL_CB_READ_ALERT,
+            SSL_CB_WRITE_ALERT,
+            SSL_CB_ACCEPT_LOOP,
+            SSL_CB_ACCEPT_EXIT,
+            SSL_CB_CONNECT_LOOP,
+            SSL_CB_CONNECT_EXIT,
+            SSL_CB_HANDSHAKE_START,
+            SSL_CB_HANDSHAKE_DONE,
         ]:
             assert isinstance(const, int)
 
         # These constants don't exist on OpenSSL 1.1.0
         for const in [
-            SSL_ST_INIT, SSL_ST_BEFORE, SSL_ST_OK, SSL_ST_RENEGOTIATE
+            SSL_ST_INIT,
+            SSL_ST_BEFORE,
+            SSL_ST_OK,
+            SSL_ST_RENEGOTIATE,
         ]:
             assert const is None or isinstance(const, int)
 
@@ -3801,6 +3949,7 @@ class TestRequires(object):
     Tests for the decorator factory used to conditionally raise
     NotImplementedError when older OpenSSLs are used.
     """
+
     def test_available(self):
         """
         When the OpenSSL functionality is available the decorated functions
@@ -3838,6 +3987,7 @@ class TestOCSP(object):
     """
     Tests for PyOpenSSL's OCSP stapling support.
     """
+
     sample_ocsp_data = b"this is totally ocsp data"
 
     def _client_connection(self, callback, data, request_ocsp=True):
@@ -3882,6 +4032,7 @@ class TestOCSP(object):
         the client does not send the OCSP request, neither callback gets
         called.
         """
+
         def ocsp_callback(*args, **kwargs):  # pragma: nocover
             pytest.fail("Should not be called")
 
@@ -3907,7 +4058,7 @@ class TestOCSP(object):
         handshake_in_memory(client, server)
 
         assert len(called) == 1
-        assert called[0] == b''
+        assert called[0] == b""
 
     def test_client_receives_servers_data(self):
         """
@@ -3990,7 +4141,7 @@ class TestOCSP(object):
         client_calls = []
 
         def server_callback(*args):
-            return b''
+            return b""
 
         def client_callback(conn, ocsp_data, ignored):
             client_calls.append(ocsp_data)
@@ -4001,12 +4152,13 @@ class TestOCSP(object):
         handshake_in_memory(client, server)
 
         assert len(client_calls) == 1
-        assert client_calls[0] == b''
+        assert client_calls[0] == b""
 
     def test_client_returns_false_terminates_handshake(self):
         """
         If the client returns False from its callback, the handshake fails.
         """
+
         def server_callback(*args):
             return self.sample_ocsp_data
 
@@ -4023,6 +4175,7 @@ class TestOCSP(object):
         """
         The callbacks thrown in the client callback bubble up to the caller.
         """
+
         class SentinelException(Exception):
             pass
 
@@ -4042,6 +4195,7 @@ class TestOCSP(object):
         """
         The callbacks thrown in the server callback bubble up to the caller.
         """
+
         class SentinelException(Exception):
             pass
 
@@ -4061,8 +4215,9 @@ class TestOCSP(object):
         """
         The server callback must return a bytestring, or a TypeError is thrown.
         """
+
         def server_callback(*args):
-            return self.sample_ocsp_data.decode('ascii')
+            return self.sample_ocsp_data.decode("ascii")
 
         def client_callback(*args):  # pragma: nocover
             pytest.fail("Should not be called")
diff --git a/tests/test_util.py b/tests/test_util.py
index 91847e0..6224448 100644
--- a/tests/test_util.py
+++ b/tests/test_util.py
@@ -7,6 +7,7 @@ class TestErrors(object):
     """
     Tests for handling of certain OpenSSL error cases.
     """
+
     def test_exception_from_error_queue_nonexistent_reason(self):
         """
         :func:`exception_from_error_queue` raises ``ValueError`` when it
diff --git a/tests/util.py b/tests/util.py
index 65b905a..75d2c8d 100644
--- a/tests/util.py
+++ b/tests/util.py
@@ -59,7 +59,7 @@ class EqualityTestsMixin(object):
         An object compares equal to itself using the C{==} operator.
         """
         o = self.anInstance()
-        assert (o == o)
+        assert o == o
 
     def test_identicalNe(self):
         """
@@ -75,7 +75,7 @@ class EqualityTestsMixin(object):
         """
         a = self.anInstance()
         b = self.anInstance()
-        assert (a == b)
+        assert a == b
 
     def test_sameNe(self):
         """
@@ -102,7 +102,7 @@ class EqualityTestsMixin(object):
         """
         a = self.anInstance()
         b = self.anotherInstance()
-        assert (a != b)
+        assert a != b
 
     def test_anotherTypeEq(self):
         """
@@ -120,13 +120,14 @@ class EqualityTestsMixin(object):
         """
         a = self.anInstance()
         b = object()
-        assert (a != b)
+        assert a != b
 
     def test_delegatedEq(self):
         """
         The result of comparison using C{==} is delegated to the right-hand
         operand if it is of an unrelated type.
         """
+
         class Delegate(object):
             def __eq__(self, other):
                 # Do something crazy and obvious.
@@ -141,6 +142,7 @@ class EqualityTestsMixin(object):
         The result of comparison using C{!=} is delegated to the right-hand
         operand if it is of an unrelated type.
         """
+
         class Delegate(object):
             def __ne__(self, other):
                 # Do something crazy and obvious.