Merge branch 'fix-imports'

13 files changed, 54 insertions, 101 deletions

diff --git a/tests/test_async.py b/tests/test_async.py
index 894d810..057deac 100755
--- a/tests/test_async.py
+++ b/tests/test_async.py
@@ -23,15 +23,15 @@
 # FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
 # License for more details.
 
+import gc
+import time
 import unittest
-from .testutils import skip_before_postgres, slow
+import warnings
 
 import psycopg2
 from psycopg2 import extensions as ext
 
-import time
-
-from .testutils import ConnectingTestCase, StringIO
+from .testutils import ConnectingTestCase, StringIO, skip_before_postgres, slow
 
 
 class PollableStub(object):
@@ -338,7 +338,6 @@ class AsyncTests(ConnectingTestCase):
         # on high load on linux: probably because the kernel has more
         # buffers ready. A warning may be useful during development,
         # but an error is bad during regression testing.
-        import warnings
         warnings.warn("sending a large query didn't trigger block on write.")
 
     def test_sync_poll(self):
@@ -427,7 +426,6 @@ class AsyncTests(ConnectingTestCase):
         self.assert_(self.conn.notices)
 
     def test_async_cursor_gone(self):
-        import gc
         cur = self.conn.cursor()
         cur.execute("select 42;")
         del cur
diff --git a/tests/test_connection.py b/tests/test_connection.py
index 1c35e8b..0ad7d37 100755
--- a/tests/test_connection.py
+++ b/tests/test_connection.py
@@ -35,11 +35,8 @@ from operator import attrgetter
 from weakref import ref
 
 import psycopg2
-import psycopg2.errorcodes
+import psycopg2.extras
 from psycopg2 import extensions as ext
-from psycopg2 import ProgrammingError
-from psycopg2.extensions import Xid
-from psycopg2.extras import RealDictConnection
 
 from .testutils import (
     unittest, skip_if_no_superuser, skip_before_postgres,
@@ -296,7 +293,6 @@ class ConnectionTests(ConnectingTestCase):
         self.assert_(not notices, "%d notices raised" % len(notices))
 
     def test_connect_cursor_factory(self):
-        import psycopg2.extras
         conn = self.connect(cursor_factory=psycopg2.extras.DictCursor)
         cur = conn.cursor()
         cur.execute("select 1 as a")
@@ -369,7 +365,7 @@ class ParseDsnTestCase(ConnectingTestCase):
             dict(user='tester', password='secret', dbname='test'),
             "simple DSN parsed")
 
-        self.assertRaises(ProgrammingError, ext.parse_dsn,
+        self.assertRaises(psycopg2.ProgrammingError, ext.parse_dsn,
                           "dbname=test 2 user=tester password=secret")
 
         self.assertEqual(
@@ -383,7 +379,7 @@ class ParseDsnTestCase(ConnectingTestCase):
         try:
             # unterminated quote after dbname:
             ext.parse_dsn("dbname='test 2 user=tester password=secret")
-        except ProgrammingError as e:
+        except psycopg2.ProgrammingError as e:
             raised = True
             self.assertTrue(str(e).find('secret') < 0,
                             "DSN was not exposed in error message")
@@ -1124,27 +1120,27 @@ class ConnectionTwoPhaseTests(ConnectingTestCase):
             cnn.tpc_rollback(xid)
 
     def test_xid_construction(self):
-        x1 = Xid(74, 'foo', 'bar')
+        x1 = ext.Xid(74, 'foo', 'bar')
         self.assertEqual(74, x1.format_id)
         self.assertEqual('foo', x1.gtrid)
         self.assertEqual('bar', x1.bqual)
 
     def test_xid_from_string(self):
-        x2 = Xid.from_string('42_Z3RyaWQ=_YnF1YWw=')
+        x2 = ext.Xid.from_string('42_Z3RyaWQ=_YnF1YWw=')
         self.assertEqual(42, x2.format_id)
         self.assertEqual('gtrid', x2.gtrid)
         self.assertEqual('bqual', x2.bqual)
 
-        x3 = Xid.from_string('99_xxx_yyy')
+        x3 = ext.Xid.from_string('99_xxx_yyy')
         self.assertEqual(None, x3.format_id)
         self.assertEqual('99_xxx_yyy', x3.gtrid)
         self.assertEqual(None, x3.bqual)
 
     def test_xid_to_string(self):
-        x1 = Xid.from_string('42_Z3RyaWQ=_YnF1YWw=')
+        x1 = ext.Xid.from_string('42_Z3RyaWQ=_YnF1YWw=')
         self.assertEqual(str(x1), '42_Z3RyaWQ=_YnF1YWw=')
 
-        x2 = Xid.from_string('99_xxx_yyy')
+        x2 = ext.Xid.from_string('99_xxx_yyy')
         self.assertEqual(str(x2), '99_xxx_yyy')
 
     def test_xid_unicode(self):
@@ -1180,7 +1176,7 @@ class ConnectionTwoPhaseTests(ConnectingTestCase):
         self.assertRaises(psycopg2.ProgrammingError, cnn.cancel)
 
     def test_tpc_recover_non_dbapi_connection(self):
-        cnn = self.connect(connection_factory=RealDictConnection)
+        cnn = self.connect(connection_factory=psycopg2.extras.RealDictConnection)
         cnn.tpc_begin('dict-connection')
         cnn.tpc_prepare()
         cnn.reset()
diff --git a/tests/test_copy.py b/tests/test_copy.py
index e800aed..05513f5 100755
--- a/tests/test_copy.py
+++ b/tests/test_copy.py
@@ -22,6 +22,7 @@
 # FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
 # License for more details.
 
+import io
 import sys
 import string
 import unittest
@@ -31,17 +32,11 @@ from subprocess import Popen, PIPE
 
 import psycopg2
 import psycopg2.extensions
-from .testutils import skip_copy_if_green
+from .testutils import skip_copy_if_green, TextIOBase
 from .testconfig import dsn
 
 
-if sys.version_info[0] < 3:
-    _base = object
-else:
-    from io import TextIOBase as _base
-
-
-class MinimalRead(_base):
+class MinimalRead(TextIOBase):
     """A file wrapper exposing the minimal interface to copy from."""
     def __init__(self, f):
         self.f = f
@@ -53,7 +48,7 @@ class MinimalRead(_base):
         return self.f.readline()
 
 
-class MinimalWrite(_base):
+class MinimalWrite(TextIOBase):
     """A file wrapper exposing the minimal interface to copy to."""
     def __init__(self, f):
         self.f = f
@@ -148,7 +143,6 @@ class CopyTests(ConnectingTestCase):
         curs.execute('insert into tcopy values (%s, %s)',
             (42, abin))
 
-        import io
         f = io.StringIO()
         curs.copy_to(f, 'tcopy', columns=('data',))
         f.seek(0)
@@ -170,7 +164,6 @@ class CopyTests(ConnectingTestCase):
         curs.execute('insert into tcopy values (%s, %s)',
             (42, abin))
 
-        import io
         f = io.BytesIO()
         curs.copy_to(f, 'tcopy', columns=('data',))
         f.seek(0)
@@ -190,7 +183,6 @@ class CopyTests(ConnectingTestCase):
                 + list(range(160, 256))).decode('latin1')
             about = abin.replace('\\', '\\\\')
 
-        import io
         f = io.StringIO()
         f.write(about)
         f.seek(0)
@@ -351,7 +343,7 @@ conn.close()
         self.assertEqual(0, proc.returncode)
 
     def test_copy_from_propagate_error(self):
-        class BrokenRead(_base):
+        class BrokenRead(TextIOBase):
             def read(self, size):
                 return 1 / 0
 
@@ -368,7 +360,7 @@ conn.close()
             self.assert_('ZeroDivisionError' in str(e))
 
     def test_copy_to_propagate_error(self):
-        class BrokenWrite(_base):
+        class BrokenWrite(TextIOBase):
             def write(self, data):
                 return 1 / 0
 
diff --git a/tests/test_cursor.py b/tests/test_cursor.py
index 675699c..47b41e6 100755
--- a/tests/test_cursor.py
+++ b/tests/test_cursor.py
@@ -22,6 +22,8 @@
 # FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
 # License for more details.
 
+import gc
+import sys
 import time
 import ctypes
 import pickle
@@ -115,7 +117,6 @@ class CursorTests(ConnectingTestCase):
         # more than once from a dict.
         cur = self.conn.cursor()
         foo = (lambda x: x)('foo') * 10
-        import sys
         nref1 = sys.getrefcount(foo)
         cur.mogrify("select %(foo)s, %(foo)s, %(foo)s", {'foo': foo})
         nref2 = sys.getrefcount(foo)
@@ -168,7 +169,6 @@ class CursorTests(ConnectingTestCase):
         curs = self.conn.cursor()
         w = ref(curs)
         del curs
-        import gc
         gc.collect()
         self.assert_(w() is None)
 
diff --git a/tests/test_dates.py b/tests/test_dates.py
index 0c1c504..5829822 100755
--- a/tests/test_dates.py
+++ b/tests/test_dates.py
@@ -23,14 +23,20 @@
 # License for more details.
 
 import math
+import pickle
 from datetime import date, datetime, time, timedelta
 
 import psycopg2
-import psycopg2.tz
 from psycopg2.tz import FixedOffsetTimezone, ZERO
 import unittest
 from .testutils import ConnectingTestCase, skip_before_postgres
 
+try:
+    from mx.DateTime import Date, Time, DateTime, DateTimeDeltaFrom
+except ImportError:
+    # Tests will be skipped
+    pass
+
 
 def total_seconds(d):
     """Return total number of seconds of a timedelta as a float."""
@@ -278,7 +284,7 @@ class DatetimeTests(ConnectingTestCase, CommonDatetimeTestsMixin):
         self.assertEqual(None, dt.tzinfo)
 
     def test_type_roundtrip_datetimetz(self):
-        tz = psycopg2.tz.FixedOffsetTimezone(8 * 60)
+        tz = FixedOffsetTimezone(8 * 60)
         dt1 = datetime(2010, 5, 3, 10, 20, 30, tzinfo=tz)
         dt2 = self._test_type_roundtrip(dt1)
         self.assertNotEqual(None, dt2.tzinfo)
@@ -289,7 +295,7 @@ class DatetimeTests(ConnectingTestCase, CommonDatetimeTestsMixin):
         self.assertEqual(None, tm.tzinfo)
 
     def test_type_roundtrip_timetz(self):
-        tz = psycopg2.tz.FixedOffsetTimezone(8 * 60)
+        tz = FixedOffsetTimezone(8 * 60)
         tm1 = time(10, 20, 30, tzinfo=tz)
         tm2 = self._test_type_roundtrip(tm1)
         self.assertNotEqual(None, tm2.tzinfo)
@@ -487,7 +493,6 @@ class mxDateTimeTests(ConnectingTestCase, CommonDatetimeTestsMixin):
 
     def test_parse_time_timezone(self):
         # Time zone information is ignored.
-        from mx.DateTime import Time
         expected = Time(13, 30, 29)
         self.assertEqual(expected, self.TIME("13:30:29+01", self.curs))
         self.assertEqual(expected, self.TIME("13:30:29-01", self.curs))
@@ -498,7 +503,6 @@ class mxDateTimeTests(ConnectingTestCase, CommonDatetimeTestsMixin):
 
     def test_parse_datetime_timezone(self):
         # Time zone information is ignored.
-        from mx.DateTime import DateTime
         expected = DateTime(2007, 1, 1, 13, 30, 29)
         self.assertEqual(
             expected, self.DATETIME("2007-01-01 13:30:29+01", self.curs))
@@ -522,19 +526,16 @@ class mxDateTimeTests(ConnectingTestCase, CommonDatetimeTestsMixin):
         self.assertEqual(value.second, 5)
 
     def test_adapt_time(self):
-        from mx.DateTime import Time
         value = self.execute('select (%s)::time::text',
                              [Time(13, 30, 29)])
         self.assertEqual(value, '13:30:29')
 
     def test_adapt_datetime(self):
-        from mx.DateTime import DateTime
         value = self.execute('select (%s)::timestamp::text',
                              [DateTime(2007, 1, 1, 13, 30, 29.123456)])
         self.assertEqual(value, '2007-01-01 13:30:29.123456')
 
     def test_adapt_bc_datetime(self):
-        from mx.DateTime import DateTime
         value = self.execute('select (%s)::timestamp::text',
                              [DateTime(-41, 1, 1, 13, 30, 29.123456)])
         # microsecs for BC timestamps look not available in PG < 8.4
@@ -544,7 +545,6 @@ class mxDateTimeTests(ConnectingTestCase, CommonDatetimeTestsMixin):
             '0042-01-01 13:30:29 BC'), value)
 
     def test_adapt_timedelta(self):
-        from mx.DateTime import DateTimeDeltaFrom
         value = self.execute('select extract(epoch from (%s)::interval)',
                              [DateTimeDeltaFrom(days=42,
                                                 seconds=45296.123456)])
@@ -553,7 +553,6 @@ class mxDateTimeTests(ConnectingTestCase, CommonDatetimeTestsMixin):
         self.assertEqual(int(round((value - seconds) * 1000000)), 123456)
 
     def test_adapt_negative_timedelta(self):
-        from mx.DateTime import DateTimeDeltaFrom
         value = self.execute('select extract(epoch from (%s)::interval)',
                              [DateTimeDeltaFrom(days=-42,
                                                 seconds=45296.123456)])
@@ -571,35 +570,27 @@ class mxDateTimeTests(ConnectingTestCase, CommonDatetimeTestsMixin):
         self.assertEqual(type(o1[0]), type(o2[0]))
 
     def test_type_roundtrip_date(self):
-        from mx.DateTime import Date
         self._test_type_roundtrip(Date(2010, 5, 3))
 
     def test_type_roundtrip_datetime(self):
-        from mx.DateTime import DateTime
         self._test_type_roundtrip(DateTime(2010, 5, 3, 10, 20, 30))
 
     def test_type_roundtrip_time(self):
-        from mx.DateTime import Time
         self._test_type_roundtrip(Time(10, 20, 30))
 
     def test_type_roundtrip_interval(self):
-        from mx.DateTime import DateTimeDeltaFrom
         self._test_type_roundtrip(DateTimeDeltaFrom(seconds=30))
 
     def test_type_roundtrip_date_array(self):
-        from mx.DateTime import Date
         self._test_type_roundtrip_array(Date(2010, 5, 3))
 
     def test_type_roundtrip_datetime_array(self):
-        from mx.DateTime import DateTime
         self._test_type_roundtrip_array(DateTime(2010, 5, 3, 10, 20, 30))
 
     def test_type_roundtrip_time_array(self):
-        from mx.DateTime import Time
         self._test_type_roundtrip_array(Time(10, 20, 30))
 
     def test_type_roundtrip_interval_array(self):
-        from mx.DateTime import DateTimeDeltaFrom
         self._test_type_roundtrip_array(DateTimeDeltaFrom(seconds=30))
 
 
@@ -659,8 +650,6 @@ class FixedOffsetTimezoneTests(unittest.TestCase):
 
     def test_pickle(self):
         # ticket #135
-        import pickle
-
         tz11 = FixedOffsetTimezone(60)
         tz12 = FixedOffsetTimezone(120)
         for proto in [-1, 0, 1, 2]:
diff --git a/tests/test_errcodes.py b/tests/test_errcodes.py
index c510f72..676d12d 100755
--- a/tests/test_errcodes.py
+++ b/tests/test_errcodes.py
@@ -25,14 +25,6 @@
 import unittest
 from .testutils import ConnectingTestCase, slow, reload
 
-try:
-    reload
-except NameError:
-    try:
-        from importlib import reload
-    except ImportError:
-        from imp import reload
-
 from threading import Thread
 from psycopg2 import errorcodes
 
diff --git a/tests/test_green.py b/tests/test_green.py
index 0f45efb..76ee1c8 100755
--- a/tests/test_green.py
+++ b/tests/test_green.py
@@ -24,6 +24,7 @@
 
 import select
 import unittest
+import warnings
 import psycopg2
 import psycopg2.extensions
 import psycopg2.extras
@@ -81,7 +82,6 @@ class GreenTestCase(ConnectingTestCase):
         # on high load on linux: probably because the kernel has more
         # buffers ready. A warning may be useful during development,
         # but an error is bad during regression testing.
-        import warnings
         warnings.warn("sending a large query didn't trigger block on write.")
 
     def test_error_in_callback(self):
diff --git a/tests/test_ipaddress.py b/tests/test_ipaddress.py
index ec67866..bf39421 100755
--- a/tests/test_ipaddress.py
+++ b/tests/test_ipaddress.py
@@ -23,16 +23,15 @@ import psycopg2
 import psycopg2.extras
 
 try:
-    import ipaddress
+    import ipaddress as ip
 except ImportError:
     # Python 2
-    ipaddress = None
+    ip = None
 
 
-@unittest.skipIf(ipaddress is None, "'ipaddress' module not available")
+@unittest.skipIf(ip is None, "'ipaddress' module not available")
 class NetworkingTestCase(testutils.ConnectingTestCase):
     def test_inet_cast(self):
-        import ipaddress as ip
         cur = self.conn.cursor()
         psycopg2.extras.register_ipaddress(cur)
 
@@ -51,7 +50,6 @@ class NetworkingTestCase(testutils.ConnectingTestCase):
 
     @testutils.skip_before_postgres(8, 2)
     def test_inet_array_cast(self):
-        import ipaddress as ip
         cur = self.conn.cursor()
         psycopg2.extras.register_ipaddress(cur)
         cur.execute("select '{NULL,127.0.0.1,::ffff:102:300/128}'::inet[]")
@@ -63,7 +61,6 @@ class NetworkingTestCase(testutils.ConnectingTestCase):
         self.assert_(isinstance(l[2], ip.IPv6Interface), l)
 
     def test_inet_adapt(self):
-        import ipaddress as ip
         cur = self.conn.cursor()
         psycopg2.extras.register_ipaddress(cur)
 
@@ -74,7 +71,6 @@ class NetworkingTestCase(testutils.ConnectingTestCase):
         self.assertEquals(cur.fetchone()[0], '::ffff:102:300/128')
 
     def test_cidr_cast(self):
-        import ipaddress as ip
         cur = self.conn.cursor()
         psycopg2.extras.register_ipaddress(cur)
 
@@ -93,7 +89,6 @@ class NetworkingTestCase(testutils.ConnectingTestCase):
 
     @testutils.skip_before_postgres(8, 2)
     def test_cidr_array_cast(self):
-        import ipaddress as ip
         cur = self.conn.cursor()
         psycopg2.extras.register_ipaddress(cur)
         cur.execute("select '{NULL,127.0.0.1,::ffff:102:300/128}'::cidr[]")
@@ -105,7 +100,6 @@ class NetworkingTestCase(testutils.ConnectingTestCase):
         self.assert_(isinstance(l[2], ip.IPv6Network), l)
 
     def test_cidr_adapt(self):
-        import ipaddress as ip
         cur = self.conn.cursor()
         psycopg2.extras.register_ipaddress(cur)
 
diff --git a/tests/test_module.py b/tests/test_module.py
index c9b9c6b..fd8ae46 100755
--- a/tests/test_module.py
+++ b/tests/test_module.py
@@ -25,6 +25,7 @@
 import gc
 import os
 import sys
+import pickle
 from subprocess import Popen
 from weakref import ref
 
@@ -285,7 +286,6 @@ class ExceptionsTestCase(ConnectingTestCase):
         self.assertEqual(e.diag.severity_nonlocalized, 'ERROR')
 
     def test_pickle(self):
-        import pickle
         cur = self.conn.cursor()
         try:
             cur.execute("select * from nonexist")
@@ -300,7 +300,6 @@ class ExceptionsTestCase(ConnectingTestCase):
 
     def test_pickle_connection_error(self):
         # segfaults on psycopg 2.5.1 - see ticket #170
-        import pickle
         try:
             psycopg2.connect('dbname=nosuchdatabasemate')
         except psycopg2.Error as exc:
diff --git a/tests/test_replication.py b/tests/test_replication.py
index 7cb4327..697d53c 100755
--- a/tests/test_replication.py
+++ b/tests/test_replication.py
@@ -22,6 +22,7 @@
 # FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
 # License for more details.
 
+import time
 from select import select
 
 import psycopg2
@@ -47,7 +48,6 @@ class ReplicationTestCase(ConnectingTestCase):
         # first close all connections, as they might keep the slot(s) active
         super(ReplicationTestCase, self).tearDown()
 
-        import time
         time.sleep(0.025)  # sometimes the slot is still active, wait a little
 
         if self._slots:
diff --git a/tests/test_types_basic.py b/tests/test_types_basic.py
index ff1dba0..13d733f 100755
--- a/tests/test_types_basic.py
+++ b/tests/test_types_basic.py
@@ -22,8 +22,10 @@
 # FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
 # License for more details.
 
+import string
 import ctypes
 import decimal
+import datetime
 import platform
 
 import sys
@@ -155,7 +157,6 @@ class TypesBasicTests(ConnectingTestCase):
 
     def testEmptyArrayRegression(self):
         # ticket #42
-        import datetime
         curs = self.conn.cursor()
         curs.execute(
             "create table array_test "
@@ -478,9 +479,6 @@ class AdaptSubclassTest(unittest.TestCase):
             del psycopg2.extensions.adapters[A, psycopg2.extensions.ISQLQuote]
 
     def test_conform_subclass_precedence(self):
-
-        import psycopg2.extensions as ext
-
         class foo(tuple):
             def __conform__(self, proto):
                 return self
@@ -488,7 +486,7 @@ class AdaptSubclassTest(unittest.TestCase):
             def getquoted(self):
                 return 'bar'
 
-        self.assertEqual(ext.adapt(foo((1, 2, 3))).getquoted(), 'bar')
+        self.assertEqual(adapt(foo((1, 2, 3))).getquoted(), 'bar')
 
 
 @unittest.skipIf(
@@ -556,7 +554,6 @@ class ByteaParserTest(unittest.TestCase):
             self.assertEqual(rv, bytes(range(256)))
 
     def test_escaped_mixed(self):
-        import string
         buf = ''.join(("\\%03o" % i) for i in range(32))
         buf += string.ascii_letters
         buf += ''.join('\\' + c for c in string.ascii_letters)
diff --git a/tests/test_types_extras.py b/tests/test_types_extras.py
index a10d476..66d4ddf 100755
--- a/tests/test_types_extras.py
+++ b/tests/test_types_extras.py
@@ -16,6 +16,8 @@
 
 import re
 import sys
+import json
+import uuid
 import warnings
 from decimal import Decimal
 from datetime import date, datetime
@@ -32,7 +34,7 @@ import psycopg2.extensions as ext
 from psycopg2._json import _get_json_oids
 from psycopg2.extras import (
     CompositeCaster, DateRange, DateTimeRange, DateTimeTZRange, HstoreAdapter,
-    Inet, Json, NumericRange, Range, RealDictConnection, json,
+    Inet, Json, NumericRange, Range, RealDictConnection,
     register_composite, register_hstore, register_range,
 )
 from psycopg2.tz import FixedOffsetTimezone
@@ -48,7 +50,6 @@ class TypesExtrasTests(ConnectingTestCase):
 
     @skip_if_no_uuid
     def testUUID(self):
-        import uuid
         psycopg2.extras.register_uuid()
         u = uuid.UUID('9c6d5a77-7256-457e-9461-347b4358e350')
         s = self.execute("SELECT %s AS foo", (u,))
@@ -59,7 +60,6 @@ class TypesExtrasTests(ConnectingTestCase):
 
     @skip_if_no_uuid
     def testUUIDARRAY(self):
-        import uuid
         psycopg2.extras.register_uuid()
         u = [uuid.UUID('9c6d5a77-7256-457e-9461-347b4358e350'),
              uuid.UUID('9c6d5a77-7256-457e-9461-347b4358e352')]
@@ -1019,7 +1019,6 @@ def skip_if_no_jsonb_type(f):
 class JsonbTestCase(ConnectingTestCase):
     @staticmethod
     def myloads(s):
-        import json
         rv = json.loads(s)
         rv['test'] = 1
         return rv
diff --git a/tests/testutils.py b/tests/testutils.py
index 8dab1b6..959b3dd 100644
--- a/tests/testutils.py
+++ b/tests/testutils.py
@@ -32,23 +32,28 @@ import platform
 import unittest
 from functools import wraps
 from ctypes.util import find_library
-from .testconfig import dsn, repl_dsn
-from psycopg2 import ProgrammingError
+
+import psycopg2
+import psycopg2.errors
+import psycopg2.extensions
 from psycopg2.compat import text_type
 
-from .testconfig import green
+from .testconfig import green, dsn, repl_dsn
 
 # Python 2/3 compatibility
 
 if sys.version_info[0] == 2:
     # Python 2
     from StringIO import StringIO
+    TextIOBase = object
     long = long
     reload = reload
     unichr = unichr
+
 else:
     # Python 3
     from io import StringIO         # noqa
+    from io import TextIOBase       # noqa
     from importlib import reload    # noqa
     long = int
     unichr = chr
@@ -116,7 +121,6 @@ class ConnectingTestCase(unittest.TestCase):
             conninfo = kwargs.pop('dsn')
         else:
             conninfo = dsn
-        import psycopg2
         conn = psycopg2.connect(conninfo, **kwargs)
         self._conns.append(conn)
         return conn
@@ -135,7 +139,6 @@ class ConnectingTestCase(unittest.TestCase):
 
         if 'dsn' not in kwargs:
             kwargs['dsn'] = repl_dsn
-        import psycopg2
         try:
             conn = self.connect(**kwargs)
             if conn.async_ == 1:
@@ -164,7 +167,6 @@ class ConnectingTestCase(unittest.TestCase):
 
     # for use with async connections only
     def wait(self, cur_or_conn):
-        import psycopg2.extensions
         pollable = cur_or_conn
         if not hasattr(pollable, 'poll'):
             pollable = cur_or_conn.connection
@@ -221,7 +223,7 @@ def decorate_all_tests(obj, *decorators):
 
 @decorate_all_tests
 def skip_if_no_uuid(f):
-    """Decorator to skip a test if uuid is not supported by Py/PG."""
+    """Decorator to skip a test if uuid is not supported by PG."""
     @wraps(f)
     def skip_if_no_uuid_(self):
         try:
@@ -248,7 +250,7 @@ def skip_if_tpc_disabled(f):
         cur = cnn.cursor()
         try:
             cur.execute("SHOW max_prepared_transactions;")
-        except ProgrammingError:
+        except psycopg2.ProgrammingError:
             return self.skipTest(
                 "server too old: two phase transactions not supported.")
         else:
@@ -306,7 +308,6 @@ def skip_after_postgres(*ver):
 
 
 def libpq_version():
-    import psycopg2
     v = psycopg2.__libpq_version__
     if v >= 90100:
         v = min(v, psycopg2.extensions.libpq_version())
@@ -372,12 +373,8 @@ def skip_if_no_superuser(f):
     def skip_if_no_superuser_(self):
         try:
             return f(self)
-        except ProgrammingError as e:
-            import psycopg2.errorcodes
-            if e.pgcode == psycopg2.errorcodes.INSUFFICIENT_PRIVILEGE:
-                self.skipTest("skipped because not superuser")
-            else:
-                raise
+        except psycopg2.errors.InsufficientPrivilege:
+            self.skipTest("skipped because not superuser")
 
     return skip_if_no_superuser_