Upgrade f-strings with flynt

25 files changed, 129 insertions, 157 deletions

diff --git a/doc/src/tools/make_sqlstate_docs.py b/doc/src/tools/make_sqlstate_docs.py
index ce6d2e7..16fd9c9 100644
--- a/doc/src/tools/make_sqlstate_docs.py
+++ b/doc/src/tools/make_sqlstate_docs.py
@@ -25,8 +25,8 @@ def main():
     for k in sorted(sqlstate_errors):
         exc = sqlstate_errors[k]
         lines.append(Line(
-            "``%s``" % k, "`!%s`" % exc.__name__,
-            "`!%s`" % get_base_exception(exc).__name__, k))
+            f"``{k}``", f"`!{exc.__name__}`",
+            f"`!{get_base_exception(exc).__name__}`", k))
 
     widths = [max(len(l[c]) for l in lines) for c in range(3)]
     h = Line(*(['=' * w for w in widths] + [None]))
@@ -39,7 +39,7 @@ def main():
     for l in lines:
         cls = l.sqlstate[:2] if l.sqlstate else None
         if cls and cls != sqlclass:
-            print("**Class {}**: {}".format(cls, sqlclasses[cls]))
+            print(f"**Class {cls}**: {sqlclasses[cls]}")
             print(h1)
             sqlclass = cls
 
diff --git a/lib/_json.py b/lib/_json.py
index 1664d06..4ceaba0 100644
--- a/lib/_json.py
+++ b/lib/_json.py
@@ -163,7 +163,7 @@ def _create_json_typecasters(oid, array_oid, loads=None, name='JSON'):
 
     JSON = new_type((oid, ), name, typecast_json)
     if array_oid is not None:
-        JSONARRAY = new_array_type((array_oid, ), "%sARRAY" % name, JSON)
+        JSONARRAY = new_array_type((array_oid, ), f"{name}ARRAY", JSON)
     else:
         JSONARRAY = None
 
@@ -194,6 +194,6 @@ def _get_json_oids(conn_or_curs, name='json'):
         conn.rollback()
 
     if not r:
-        raise conn.ProgrammingError("%s data type not found" % name)
+        raise conn.ProgrammingError(f"{name} data type not found")
 
     return r
diff --git a/lib/_range.py b/lib/_range.py
index 1db11f8..a59bab8 100644
--- a/lib/_range.py
+++ b/lib/_range.py
@@ -47,7 +47,7 @@ class Range:
     def __init__(self, lower=None, upper=None, bounds='[)', empty=False):
         if not empty:
             if bounds not in ('[)', '(]', '()', '[]'):
-                raise ValueError("bound flags not valid: %r" % bounds)
+                raise ValueError(f"bound flags not valid: {bounds!r}")
 
             self._lower = lower
             self._upper = upper
@@ -57,7 +57,7 @@ class Range:
 
     def __repr__(self):
         if self._bounds is None:
-            return "%s(empty=True)" % self.__class__.__name__
+            return f"{self.__class__.__name__}(empty=True)"
         else:
             return "{}({!r}, {!r}, {!r})".format(self.__class__.__name__,
                 self._lower, self._upper, self._bounds)
@@ -391,7 +391,7 @@ where typname = %s and ns.nspname = %s;
 
         if not rec:
             raise ProgrammingError(
-                "PostgreSQL type '%s' not found" % name)
+                f"PostgreSQL type '{name}' not found")
 
         type, subtype, array = rec
 
@@ -423,7 +423,7 @@ where typname = %s and ns.nspname = %s;
 
         m = self._re_range.match(s)
         if m is None:
-            raise InterfaceError("failed to parse range: '%s'" % s)
+            raise InterfaceError(f"failed to parse range: '{s}'")
 
         lower = m.group(3)
         if lower is None:
@@ -503,8 +503,7 @@ class NumberRangeAdapter(RangeAdapter):
         else:
             upper = ''
 
-        return ("'{}{},{}{}'".format(
-            r._bounds[0], lower, upper, r._bounds[1])).encode('ascii')
+        return (f"'{r._bounds[0]}{lower},{upper}{r._bounds[1]}'").encode('ascii')
 
 
 # TODO: probably won't work with infs, nans and other tricky cases.
diff --git a/lib/extras.py b/lib/extras.py
index 3f1da84..3fa6255 100644
--- a/lib/extras.py
+++ b/lib/extras.py
@@ -529,7 +529,7 @@ class ReplicationCursor(_replicationCursor):
     def create_replication_slot(self, slot_name, slot_type=None, output_plugin=None):
         """Create streaming replication slot."""
 
-        command = "CREATE_REPLICATION_SLOT %s " % quote_ident(slot_name, self)
+        command = f"CREATE_REPLICATION_SLOT {quote_ident(slot_name, self)} "
 
         if slot_type is None:
             slot_type = self.connection.replication_type
@@ -540,7 +540,7 @@ class ReplicationCursor(_replicationCursor):
                     "output plugin name is required to create "
                     "logical replication slot")
 
-            command += "LOGICAL %s" % quote_ident(output_plugin, self)
+            command += f"LOGICAL {quote_ident(output_plugin, self)}"
 
         elif slot_type == REPLICATION_PHYSICAL:
             if output_plugin is not None:
@@ -552,14 +552,14 @@ class ReplicationCursor(_replicationCursor):
 
         else:
             raise psycopg2.ProgrammingError(
-                "unrecognized replication type: %s" % repr(slot_type))
+                f"unrecognized replication type: {repr(slot_type)}")
 
         self.execute(command)
 
     def drop_replication_slot(self, slot_name):
         """Drop streaming replication slot."""
 
-        command = "DROP_REPLICATION_SLOT %s" % quote_ident(slot_name, self)
+        command = f"DROP_REPLICATION_SLOT {quote_ident(slot_name, self)}"
         self.execute(command)
 
     def start_replication(
@@ -574,7 +574,7 @@ class ReplicationCursor(_replicationCursor):
 
         if slot_type == REPLICATION_LOGICAL:
             if slot_name:
-                command += "SLOT %s " % quote_ident(slot_name, self)
+                command += f"SLOT {quote_ident(slot_name, self)} "
             else:
                 raise psycopg2.ProgrammingError(
                     "slot name is required for logical replication")
@@ -583,19 +583,18 @@ class ReplicationCursor(_replicationCursor):
 
         elif slot_type == REPLICATION_PHYSICAL:
             if slot_name:
-                command += "SLOT %s " % quote_ident(slot_name, self)
+                command += f"SLOT {quote_ident(slot_name, self)} "
             # don't add "PHYSICAL", before 9.4 it was just START_REPLICATION XXX/XXX
 
         else:
             raise psycopg2.ProgrammingError(
-                "unrecognized replication type: %s" % repr(slot_type))
+                f"unrecognized replication type: {repr(slot_type)}")
 
         if type(start_lsn) is str:
             lsn = start_lsn.split('/')
-            lsn = "{:X}/{:08X}".format(int(lsn[0], 16), int(lsn[1], 16))
+            lsn = f"{int(lsn[0], 16):X}/{int(lsn[1], 16):08X}"
         else:
-            lsn = "{:X}/{:08X}".format((start_lsn >> 32) & 0xFFFFFFFF,
-                               start_lsn & 0xFFFFFFFF)
+            lsn = f"{start_lsn >> 32 & 4294967295:X}/{start_lsn & 4294967295:08X}"
 
         command += lsn
 
@@ -615,7 +614,7 @@ class ReplicationCursor(_replicationCursor):
             for k, v in options.items():
                 if not command.endswith('('):
                     command += ", "
-                command += "{} {}".format(quote_ident(k, self), _A(str(v)))
+                command += f"{quote_ident(k, self)} {_A(str(v))}"
             command += ")"
 
         self.start_replication_expert(
@@ -643,10 +642,10 @@ class UUID_adapter:
             return self
 
     def getquoted(self):
-        return ("'%s'::uuid" % self._uuid).encode('utf8')
+        return (f"'{self._uuid}'::uuid").encode('utf8')
 
     def __str__(self):
-        return "'%s'::uuid" % self._uuid
+        return f"'{self._uuid}'::uuid"
 
 
 def register_uuid(oids=None, conn_or_curs=None):
@@ -768,7 +767,7 @@ def wait_select(conn):
             elif state == POLL_WRITE:
                 select.select([], [conn.fileno()], [])
             else:
-                raise conn.OperationalError("bad state from poll: %s" % state)
+                raise conn.OperationalError(f"bad state from poll: {state}")
         except KeyboardInterrupt:
             conn.cancel()
             # the loop will be broken by a server error
@@ -909,12 +908,11 @@ class HstoreAdapter:
         rv0, rv1 = [], []
 
         # get the oid for the hstore
-        curs.execute("""\
-SELECT t.oid, %s
+        curs.execute(f"""SELECT t.oid, {typarray}
 FROM pg_type t JOIN pg_namespace ns
     ON typnamespace = ns.oid
 WHERE typname = 'hstore';
-""" % typarray)
+""")
         for oids in curs:
             rv0.append(oids[0])
             rv1.append(oids[1])
@@ -1008,7 +1006,7 @@ class CompositeCaster:
         self.typecaster = _ext.new_type((oid,), name, self.parse)
         if array_oid:
             self.array_typecaster = _ext.new_array_type(
-                (array_oid,), "%sARRAY" % name, self.typecaster)
+                (array_oid,), f"{name}ARRAY", self.typecaster)
         else:
             self.array_typecaster = None
 
@@ -1052,7 +1050,7 @@ class CompositeCaster:
         rv = []
         for m in self._re_tokenize.finditer(s):
             if m is None:
-                raise psycopg2.InterfaceError("can't parse type: %r" % s)
+                raise psycopg2.InterfaceError(f"can't parse type: {s!r}")
             if m.group(1) is not None:
                 rv.append(None)
             elif m.group(2) is not None:
@@ -1107,7 +1105,7 @@ ORDER BY attnum;
 
         if not recs:
             raise psycopg2.ProgrammingError(
-                "PostgreSQL type '%s' not found" % name)
+                f"PostgreSQL type '{name}' not found")
 
         type_oid = recs[0][0]
         array_oid = recs[0][1]
diff --git a/lib/sql.py b/lib/sql.py
index aeff748..47c825b 100644
--- a/lib/sql.py
+++ b/lib/sql.py
@@ -106,7 +106,7 @@ class Composed(Composable):
         for i in seq:
             if not isinstance(i, Composable):
                 raise TypeError(
-                    "Composed elements must be Composable, got %r instead" % i)
+                    f"Composed elements must be Composable, got {i!r} instead")
             wrapped.append(i)
 
         super().__init__(wrapped)
@@ -344,9 +344,7 @@ class Identifier(Composable):
                 "the Identifier wraps more than one than one string")
 
     def __repr__(self):
-        return "{}({})".format(
-            self.__class__.__name__,
-            ', '.join(map(repr, self._wrapped)))
+        return f"{self.__class__.__name__}({', '.join(map(repr, self._wrapped))})"
 
     def as_string(self, context):
         return '.'.join(ext.quote_ident(s, context) for s in self._wrapped)
@@ -427,10 +425,10 @@ class Placeholder(Composable):
     def __init__(self, name=None):
         if isinstance(name, str):
             if ')' in name:
-                raise ValueError("invalid name: %r" % name)
+                raise ValueError(f"invalid name: {name!r}")
 
         elif name is not None:
-            raise TypeError("expected string or None as name, got %r" % name)
+            raise TypeError(f"expected string or None as name, got {name!r}")
 
         super().__init__(name)
 
@@ -440,12 +438,11 @@ class Placeholder(Composable):
         return self._wrapped
 
     def __repr__(self):
-        return "Placeholder({!r})".format(
-            self._wrapped if self._wrapped is not None else '')
+        return f"Placeholder({self._wrapped if self._wrapped is not None else ''!r})"
 
     def as_string(self, context):
         if self._wrapped is not None:
-            return "%%(%s)s" % self._wrapped
+            return f"%{self._wrapped['%s']}"
         else:
             return "%s"
 
diff --git a/scripts/appveyor.py b/scripts/appveyor.py
index d2cb76d..7c9d3ba 100755
--- a/scripts/appveyor.py
+++ b/scripts/appveyor.py
@@ -439,10 +439,7 @@ def check_libpq_version():
         .decode('ascii')
         .rstrip()
     )
-    assert want_ver == got_ver, "libpq version mismatch: {!r} != {!r}".format(
-        want_ver,
-        got_ver,
-    )
+    assert want_ver == got_ver, f"libpq version mismatch: {want_ver!r} != {got_ver!r}"
 
 
 def run_test_suite():
@@ -684,7 +681,7 @@ def which(name):
             if os.path.isfile(fn):
                 return fn
 
-    raise Exception("couldn't find program on path: %s" % name)
+    raise Exception(f"couldn't find program on path: {name}")
 
 
 class Options:
@@ -846,7 +843,7 @@ class Options:
     def dist_dir(self):
         """The directory where to build packages to distribute."""
         return (
-            self.package_dir / 'dist' / ('psycopg2-%s' % self.package_version)
+            self.package_dir / 'dist' / (f'psycopg2-{self.package_version}')
         )
 
 
diff --git a/scripts/make_errorcodes.py b/scripts/make_errorcodes.py
index 49ae8d5..0c07f37 100755
--- a/scripts/make_errorcodes.py
+++ b/scripts/make_errorcodes.py
@@ -25,7 +25,7 @@ from collections import defaultdict
 
 def main():
     if len(sys.argv) != 2:
-        print("usage: %s /path/to/errorcodes.py" % sys.argv[0], file=sys.stderr)
+        print(f"usage: {sys.argv[0]} /path/to/errorcodes.py", file=sys.stderr)
         return 2
 
     filename = sys.argv[1]
@@ -84,7 +84,7 @@ def parse_errors_txt(url):
             continue
 
         # We don't expect anything else
-        raise ValueError("unexpected line:\n%s" % line)
+        raise ValueError(f"unexpected line:\n{line}")
 
     return classes, errors
 
@@ -101,9 +101,7 @@ def fetch_errors(versions):
     for version in versions:
         print(version, file=sys.stderr)
         tver = tuple(map(int, version.split()[0].split('.')))
-        tag = '{}{}_STABLE'.format(
-            (tver[0] >= 10 and 'REL_' or 'REL'),
-            version.replace('.', '_'))
+        tag = f"{tver[0] >= 10 and 'REL_' or 'REL'}{version.replace('.', '_')}_STABLE"
         c1, e1 = parse_errors_txt(errors_txt_url % tag)
         classes.update(c1)
 
@@ -141,11 +139,11 @@ def generate_module_data(classes, errors):
 
     for clscode, clslabel in sorted(classes.items()):
         yield ""
-        yield "# %s" % clslabel
+        yield f"# {clslabel}"
 
         for errcode, errlabel in sorted(errors[clscode].items()):
             if errlabel in seen:
-                raise Exception("error label already seen: %s" % errlabel)
+                raise Exception(f"error label already seen: {errlabel}")
             seen.add(errlabel)
             yield f"{errlabel} = {errcode!r}"
 
diff --git a/scripts/make_errors.py b/scripts/make_errors.py
index e36d00a..0b795fa 100755
--- a/scripts/make_errors.py
+++ b/scripts/make_errors.py
@@ -68,7 +68,7 @@ def parse_errors_txt(url):
             continue
 
         # We don't expect anything else
-        raise ValueError("unexpected line:\n%s" % line)
+        raise ValueError(f"unexpected line:\n{line}")
 
     return classes, errors
 
@@ -85,9 +85,7 @@ def fetch_errors(versions):
     for version in versions:
         print(version, file=sys.stderr)
         tver = tuple(map(int, version.split()[0].split('.')))
-        tag = '{}{}_STABLE'.format(
-            (tver[0] >= 10 and 'REL_' or 'REL'),
-            version.replace('.', '_'))
+        tag = f"{tver[0] >= 10 and 'REL_' or 'REL'}{version.replace('.', '_')}_STABLE"
         c1, e1 = parse_errors_txt(errors_txt_url % tag)
         classes.update(c1)
 
@@ -118,7 +116,7 @@ def generate_module_data(classes, errors):
             # success and warning - never raised
             continue
 
-        yield "\n/* %s */" % clslabel
+        yield f"\n/* {clslabel} */"
 
         for errcode, errlabel in sorted(errors[clscode].items()):
             if errcode in specific:
@@ -126,7 +124,7 @@ def generate_module_data(classes, errors):
             else:
                 clsname = errlabel.title().replace('_', '')
             if clsname in seen:
-                raise Exception("class already existing: %s" % clsname)
+                raise Exception(f"class already existing: {clsname}")
             seen.add(clsname)
 
             yield tmpl % {
diff --git a/scripts/refcounter.py b/scripts/refcounter.py
index 683a0c0..efe69a3 100755
--- a/scripts/refcounter.py
+++ b/scripts/refcounter.py
@@ -36,7 +36,7 @@ def main():
     if opt.suite:
         test = getattr(test, opt.suite)
 
-    sys.stdout.write("test suite %s\n" % test.__name__)
+    sys.stdout.write(f"test suite {test.__name__}\n")
 
     for i in range(1, opt.nruns + 1):
         sys.stdout.write("test suite run %d of %d\n" % (i, opt.nruns))
diff --git a/setup.py b/setup.py
index 80d7391..a563fd1 100644
--- a/setup.py
+++ b/setup.py
@@ -114,8 +114,7 @@ For further information please check the 'doc/src/install.rst' file (also at
                 stdout=subprocess.PIPE,
                 stderr=subprocess.PIPE)
         except OSError:
-            raise Warning("Unable to find 'pg_config' file in '%s'" %
-                          self.pg_config_exe)
+            raise Warning(f"Unable to find 'pg_config' file in '{self.pg_config_exe}'")
         pg_config_process.stdin.close()
         result = pg_config_process.stdout.readline().strip()
         if not result:
@@ -396,8 +395,7 @@ For further information please check the 'doc/src/install.rst' file (also at
                 pgpatch = int(pgpatch)
             else:
                 sys.stderr.write(
-                    "Error: could not determine PostgreSQL version from '%s'"
-                    % pgversion)
+                    f"Error: could not determine PostgreSQL version from '{pgversion}'")
                 sys.exit(1)
 
             define_macros.append(("PG_VERSION_NUM", "%d%02d%02d" %
@@ -419,7 +417,7 @@ For further information please check the 'doc/src/install.rst' file (also at
 
         except Warning:
             w = sys.exc_info()[1]  # work around py 2/3 different syntax
-            sys.stderr.write("Error: %s\n" % w)
+            sys.stderr.write(f"Error: {w}\n")
             sys.exit(1)
 
         if hasattr(self, "finalize_" + sys.platform):
@@ -512,7 +510,7 @@ version_flags.append('pq3')     # no more a choice
 version_flags.append('ext')     # no more a choice
 
 if version_flags:
-    PSYCOPG_VERSION_EX = PSYCOPG_VERSION + " (%s)" % ' '.join(version_flags)
+    PSYCOPG_VERSION_EX = PSYCOPG_VERSION + f" ({' '.join(version_flags)})"
 else:
     PSYCOPG_VERSION_EX = PSYCOPG_VERSION
 
diff --git a/tests/dbapi20.py b/tests/dbapi20.py
index b96af09..5a98b4a 100644
--- a/tests/dbapi20.py
+++ b/tests/dbapi20.py
@@ -101,10 +101,10 @@ class DatabaseAPI20Test(unittest.TestCase):
     connect_kw_args = {} # Keyword arguments for connect
     table_prefix = 'dbapi20test_' # If you need to specify a prefix for tables
 
-    ddl1 = 'create table %sbooze (name varchar(20))' % table_prefix
-    ddl2 = 'create table %sbarflys (name varchar(20))' % table_prefix
-    xddl1 = 'drop table %sbooze' % table_prefix
-    xddl2 = 'drop table %sbarflys' % table_prefix
+    ddl1 = f'create table {table_prefix}booze (name varchar(20))'
+    ddl2 = f'create table {table_prefix}barflys (name varchar(20))'
+    xddl1 = f'drop table {table_prefix}booze'
+    xddl2 = f'drop table {table_prefix}barflys'
 
     lowerfunc = 'lower' # Name of stored procedure to convert string->lowercase
 
@@ -265,7 +265,7 @@ class DatabaseAPI20Test(unittest.TestCase):
             cur1.execute("insert into %sbooze values ('Victoria Bitter')" % (
                 self.table_prefix
                 ))
-            cur2.execute("select name from %sbooze" % self.table_prefix)
+            cur2.execute(f"select name from {self.table_prefix}booze")
             booze = cur2.fetchall()
             self.assertEqual(len(booze),1)
             self.assertEqual(len(booze[0]),1)
@@ -282,7 +282,7 @@ class DatabaseAPI20Test(unittest.TestCase):
                 'cursor.description should be none after executing a '
                 'statement that can return no rows (such as DDL)'
                 )
-            cur.execute('select name from %sbooze' % self.table_prefix)
+            cur.execute(f'select name from {self.table_prefix}booze')
             self.assertEqual(len(cur.description),1,
                 'cursor.description describes too many columns'
                 )
@@ -322,7 +322,7 @@ class DatabaseAPI20Test(unittest.TestCase):
                 'cursor.rowcount should == number or rows inserted, or '
                 'set to -1 after executing an insert statement'
                 )
-            cur.execute("select name from %sbooze" % self.table_prefix)
+            cur.execute(f"select name from {self.table_prefix}booze")
             self.failUnless(cur.rowcount in (-1,1),
                 'cursor.rowcount should == number of rows returned, or '
                 'set to -1 after executing a select statement'
@@ -385,24 +385,22 @@ class DatabaseAPI20Test(unittest.TestCase):
 
     def _paraminsert(self,cur):
         self.executeDDL1(cur)
-        cur.execute("insert into %sbooze values ('Victoria Bitter')" % (
-            self.table_prefix
-            ))
+        cur.execute(f"insert into {self.table_prefix}booze values ('Victoria Bitter')")
         self.failUnless(cur.rowcount in (-1,1))
 
         if self.driver.paramstyle == 'qmark':
             cur.execute(
-                'insert into %sbooze values (?)' % self.table_prefix,
+                f'insert into {self.table_prefix}booze values (?)',
                 ("Cooper's",)
                 )
         elif self.driver.paramstyle == 'numeric':
             cur.execute(
-                'insert into %sbooze values (:1)' % self.table_prefix,
+                f'insert into {self.table_prefix}booze values (:1)',
                 ("Cooper's",)
                 )
         elif self.driver.paramstyle == 'named':
             cur.execute(
-                'insert into %sbooze values (:beer)' % self.table_prefix,
+                f'insert into {self.table_prefix}booze values (:beer)',
                 {'beer':"Cooper's"}
                 )
         elif self.driver.paramstyle == 'format':
@@ -412,14 +410,14 @@ class DatabaseAPI20Test(unittest.TestCase):
                 )
         elif self.driver.paramstyle == 'pyformat':
             cur.execute(
-                'insert into %sbooze values (%%(beer)s)' % self.table_prefix,
+                f"insert into %sbooze values (%{self.table_prefix['beer']})",
                 {'beer':"Cooper's"}
                 )
         else:
             self.fail('Invalid paramstyle')
         self.failUnless(cur.rowcount in (-1,1))
 
-        cur.execute('select name from %sbooze' % self.table_prefix)
+        cur.execute(f'select name from {self.table_prefix}booze')
         res = cur.fetchall()
         self.assertEqual(len(res),2,'cursor.fetchall returned too few rows')
         beers = [res[0][0],res[1][0]]
@@ -442,17 +440,17 @@ class DatabaseAPI20Test(unittest.TestCase):
             margs = [ {'beer': "Cooper's"}, {'beer': "Boag's"} ]
             if self.driver.paramstyle == 'qmark':
                 cur.executemany(
-                    'insert into %sbooze values (?)' % self.table_prefix,
+                    f'insert into {self.table_prefix}booze values (?)',
                     largs
                     )
             elif self.driver.paramstyle == 'numeric':
                 cur.executemany(
-                    'insert into %sbooze values (:1)' % self.table_prefix,
+                    f'insert into {self.table_prefix}booze values (:1)',
                     largs
                     )
             elif self.driver.paramstyle == 'named':
                 cur.executemany(
-                    'insert into %sbooze values (:beer)' % self.table_prefix,
+                    f'insert into {self.table_prefix}booze values (:beer)',
                     margs
                     )
             elif self.driver.paramstyle == 'format':
@@ -462,9 +460,7 @@ class DatabaseAPI20Test(unittest.TestCase):
                     )
             elif self.driver.paramstyle == 'pyformat':
                 cur.executemany(
-                    'insert into %sbooze values (%%(beer)s)' % (
-                        self.table_prefix
-                        ),
+                    f"insert into %sbooze values (%{self.table_prefix['beer']})",
                     margs
                     )
             else:
@@ -473,7 +469,7 @@ class DatabaseAPI20Test(unittest.TestCase):
                 'insert using cursor.executemany set cursor.rowcount to '
                 'incorrect value %r' % cur.rowcount
                 )
-            cur.execute('select name from %sbooze' % self.table_prefix)
+            cur.execute(f'select name from {self.table_prefix}booze')
             res = cur.fetchall()
             self.assertEqual(len(res),2,
                 'cursor.fetchall retrieved incorrect number of rows'
@@ -499,7 +495,7 @@ class DatabaseAPI20Test(unittest.TestCase):
             self.executeDDL1(cur)
             self.assertRaises(self.driver.Error,cur.fetchone)
 
-            cur.execute('select name from %sbooze' % self.table_prefix)
+            cur.execute(f'select name from {self.table_prefix}booze')
             self.assertEqual(cur.fetchone(),None,
                 'cursor.fetchone should return None if a query retrieves '
                 'no rows'
@@ -513,7 +509,7 @@ class DatabaseAPI20Test(unittest.TestCase):
                 ))
             self.assertRaises(self.driver.Error,cur.fetchone)
 
-            cur.execute('select name from %sbooze' % self.table_prefix)
+            cur.execute(f'select name from {self.table_prefix}booze')
             r = cur.fetchone()
             self.assertEqual(len(r),1,
                 'cursor.fetchone should have retrieved a single row'
@@ -560,7 +556,7 @@ class DatabaseAPI20Test(unittest.TestCase):
             for sql in self._populate():
                 cur.execute(sql)
 
-            cur.execute('select name from %sbooze' % self.table_prefix)
+            cur.execute(f'select name from {self.table_prefix}booze')
             r = cur.fetchmany()
             self.assertEqual(len(r),1,
                 'cursor.fetchmany retrieved incorrect number of rows, '
@@ -584,7 +580,7 @@ class DatabaseAPI20Test(unittest.TestCase):
 
             # Same as above, using cursor.arraysize
             cur.arraysize=4
-            cur.execute('select name from %sbooze' % self.table_prefix)
+            cur.execute(f'select name from {self.table_prefix}booze')
             r = cur.fetchmany() # Should get 4 rows
             self.assertEqual(len(r),4,
                 'cursor.arraysize not being honoured by fetchmany'
@@ -596,7 +592,7 @@ class DatabaseAPI20Test(unittest.TestCase):
             self.failUnless(cur.rowcount in (-1,6))
 
             cur.arraysize=6
-            cur.execute('select name from %sbooze' % self.table_prefix)
+            cur.execute(f'select name from {self.table_prefix}booze')
             rows = cur.fetchmany() # Should get all rows
             self.failUnless(cur.rowcount in (-1,6))
             self.assertEqual(len(rows),6)
@@ -618,7 +614,7 @@ class DatabaseAPI20Test(unittest.TestCase):
             self.failUnless(cur.rowcount in (-1,6))
 
             self.executeDDL2(cur)
-            cur.execute('select name from %sbarflys' % self.table_prefix)
+            cur.execute(f'select name from {self.table_prefix}barflys')
             r = cur.fetchmany() # Should get empty sequence
             self.assertEqual(len(r),0,
                 'cursor.fetchmany should return an empty sequence if '
@@ -646,7 +642,7 @@ class DatabaseAPI20Test(unittest.TestCase):
             # after executing a a statement that cannot return rows
             self.assertRaises(self.driver.Error,cur.fetchall)
 
-            cur.execute('select name from %sbooze' % self.table_prefix)
+            cur.execute(f'select name from {self.table_prefix}booze')
             rows = cur.fetchall()
             self.failUnless(cur.rowcount in (-1,len(self.samples)))
             self.assertEqual(len(rows),len(self.samples),
@@ -667,7 +663,7 @@ class DatabaseAPI20Test(unittest.TestCase):
             self.failUnless(cur.rowcount in (-1,len(self.samples)))
 
             self.executeDDL2(cur)
-            cur.execute('select name from %sbarflys' % self.table_prefix)
+            cur.execute(f'select name from {self.table_prefix}barflys')
             rows = cur.fetchall()
             self.failUnless(cur.rowcount in (-1,0))
             self.assertEqual(len(rows),0,
@@ -686,7 +682,7 @@ class DatabaseAPI20Test(unittest.TestCase):
             for sql in self._populate():
                 cur.execute(sql)
 
-            cur.execute('select name from %sbooze' % self.table_prefix)
+            cur.execute(f'select name from {self.table_prefix}booze')
             rows1  = cur.fetchone()
             rows23 = cur.fetchmany(2)
             rows4  = cur.fetchone()
@@ -803,8 +799,8 @@ class DatabaseAPI20Test(unittest.TestCase):
         try:
             cur = con.cursor()
             self.executeDDL1(cur)
-            cur.execute('insert into %sbooze values (NULL)' % self.table_prefix)
-            cur.execute('select name from %sbooze' % self.table_prefix)
+            cur.execute(f'insert into {self.table_prefix}booze values (NULL)')
+            cur.execute(f'select name from {self.table_prefix}booze')
             r = cur.fetchall()
             self.assertEqual(len(r),1)
             self.assertEqual(len(r[0]),1)
diff --git a/tests/test_connection.py b/tests/test_connection.py
index 5fb7670..dc1d446 100755
--- a/tests/test_connection.py
+++ b/tests/test_connection.py
@@ -383,8 +383,7 @@ class ConnectionTests(ConnectingTestCase):
         dir = tempfile.mkdtemp()
         try:
             with open(os.path.join(dir, "mptest.py"), 'w') as f:
-                f.write("""\
-import time
+                f.write(f"""import time
 import psycopg2
 
 def thread():
@@ -396,7 +395,7 @@ def thread():
 
 def process():
     time.sleep(0.2)
-""".format(dsn=dsn))
+""")
 
             script = ("""\
 import sys
@@ -1732,8 +1731,7 @@ class SignalTestCase(ConnectingTestCase):
             """)
 
     def _test_bug_551(self, query):
-        script = ("""\
-import os
+        script = f"""import os
 import sys
 import time
 import signal
@@ -1766,7 +1764,7 @@ t.start()
 
 while True:
     cur.execute({query!r}, ("Hello, world!",))
-""".format(dsn=dsn, query=query))
+"""
 
         proc = sp.Popen([sys.executable, '-c', script],
             stdout=sp.PIPE, stderr=sp.PIPE)
diff --git a/tests/test_copy.py b/tests/test_copy.py
index e48e3bd..a8e8ff9 100755
--- a/tests/test_copy.py
+++ b/tests/test_copy.py
@@ -317,8 +317,7 @@ class CopyTests(ConnectingTestCase):
     @slow
     def test_copy_from_segfault(self):
         # issue #219
-        script = ("""\
-import psycopg2
+        script = f"""import psycopg2
 conn = psycopg2.connect({dsn!r})
 curs = conn.cursor()
 curs.execute("create table copy_segf (id int)")
@@ -327,7 +326,7 @@ try:
 except psycopg2.ProgrammingError:
     pass
 conn.close()
-""".format(dsn=dsn))
+"""
 
         proc = Popen([sys.executable, '-c', script])
         proc.communicate()
@@ -336,8 +335,7 @@ conn.close()
     @slow
     def test_copy_to_segfault(self):
         # issue #219
-        script = ("""\
-import psycopg2
+        script = f"""import psycopg2
 conn = psycopg2.connect({dsn!r})
 curs = conn.cursor()
 curs.execute("create table copy_segf (id int)")
@@ -346,7 +344,7 @@ try:
 except psycopg2.ProgrammingError:
     pass
 conn.close()
-""".format(dsn=dsn))
+"""
 
         proc = Popen([sys.executable, '-c', script], stdout=PIPE)
         proc.communicate()
diff --git a/tests/test_cursor.py b/tests/test_cursor.py
index 1b5b620..391af56 100755
--- a/tests/test_cursor.py
+++ b/tests/test_cursor.py
@@ -88,21 +88,21 @@ class CursorTests(ConnectingTestCase):
                 return s
 
         # unicode query with non-ascii data
-        cur.execute("SELECT '%s';" % snowman)
+        cur.execute(f"SELECT '{snowman}';")
         self.assertEqual(snowman.encode('utf8'), b(cur.fetchone()[0]))
-        self.assertQuotedEqual(("SELECT '%s';" % snowman).encode('utf8'),
-            cur.mogrify("SELECT '%s';" % snowman))
+        self.assertQuotedEqual(f"SELECT '{snowman}';".encode('utf8'),
+            cur.mogrify(f"SELECT '{snowman}';"))
 
         # unicode args
         cur.execute("SELECT %s;", (snowman,))
         self.assertEqual(snowman.encode("utf-8"), b(cur.fetchone()[0]))
-        self.assertQuotedEqual(("SELECT '%s';" % snowman).encode('utf8'),
+        self.assertQuotedEqual(f"SELECT '{snowman}';".encode('utf8'),
             cur.mogrify("SELECT %s;", (snowman,)))
 
         # unicode query and args
         cur.execute("SELECT %s;", (snowman,))
         self.assertEqual(snowman.encode("utf-8"), b(cur.fetchone()[0]))
-        self.assertQuotedEqual(("SELECT '%s';" % snowman).encode('utf8'),
+        self.assertQuotedEqual(f"SELECT '{snowman}';".encode('utf8'),
             cur.mogrify("SELECT %s;", (snowman,)))
 
     def test_mogrify_decimal_explodes(self):
@@ -282,12 +282,12 @@ class CursorTests(ConnectingTestCase):
         cur = self.conn.cursor()
 
         # Set up the temporary function
-        cur.execute('''
-            CREATE FUNCTION {}({} INT)
+        cur.execute(f'''
+            CREATE FUNCTION {procname}({escaped_paramname} INT)
             RETURNS INT AS
                 'SELECT $1 * $1'
             LANGUAGE SQL
-        '''.format(procname, escaped_paramname))
+        ''')
 
         # Make sure callproc works right
         cur.callproc(procname, {paramname: 2})
@@ -573,8 +573,7 @@ class NamedCursorTests(ConnectingTestCase):
         time.sleep(0.2)
         t2 = next(i)[0]
         self.assert_((t2 - t1).microseconds * 1e-6 < 0.1,
-            "named cursor records fetched in 2 roundtrips (delta: %s)"
-            % (t2 - t1))
+            f"named cursor records fetched in 2 roundtrips (delta: {t2 - t1})")
 
     @skip_before_postgres(8, 0)
     def test_iter_named_cursor_default_itersize(self):
diff --git a/tests/test_dates.py b/tests/test_dates.py
index fb50abe..29c37b0 100755
--- a/tests/test_dates.py
+++ b/tests/test_dates.py
@@ -379,7 +379,7 @@ class DatetimeTests(ConnectingTestCase, CommonDatetimeTestsMixin):
             cur)
 
         def f(val):
-            cur.execute("select '%s'::text" % val)
+            cur.execute(f"select '{val}'::text")
             return cur.fetchone()[0]
 
         self.assertRaises(OverflowError, f, '100000000000000000:00:00')
diff --git a/tests/test_extras_dictcursor.py b/tests/test_extras_dictcursor.py
index e52ad4a..4c63db7 100755
--- a/tests/test_extras_dictcursor.py
+++ b/tests/test_extras_dictcursor.py
@@ -621,7 +621,7 @@ class NamedTupleCursorTest(ConnectingTestCase):
             recs = []
             curs = self.conn.cursor()
             for i in range(10):
-                curs.execute("select 1 as f%s" % i)
+                curs.execute(f"select 1 as f{i}")
                 recs.append(curs.fetchone())
 
             # Still in cache
diff --git a/tests/test_green.py b/tests/test_green.py
index e4e93a6..fa9f298 100755
--- a/tests/test_green.py
+++ b/tests/test_green.py
@@ -137,7 +137,7 @@ class GreenTestCase(ConnectingTestCase):
                 elif state == POLL_WRITE:
                     select.select([], [conn.fileno()], [], 0.1)
                 else:
-                    raise conn.OperationalError("bad state from poll: %s" % state)
+                    raise conn.OperationalError(f"bad state from poll: {state}")
 
         stub = self.set_stub_wait_callback(self.conn, wait)
         cur = self.conn.cursor()
@@ -182,7 +182,7 @@ class CallbackErrorTestCase(ConnectingTestCase):
                 elif state == POLL_WRITE:
                     select.select([], [conn.fileno()], [])
                 else:
-                    raise conn.OperationalError("bad state from poll: %s" % state)
+                    raise conn.OperationalError(f"bad state from poll: {state}")
             except KeyboardInterrupt:
                 conn.cancel()
                 # the loop will be broken by a server error
diff --git a/tests/test_lobject.py b/tests/test_lobject.py
index 6088b28..8d94656 100755
--- a/tests/test_lobject.py
+++ b/tests/test_lobject.py
@@ -207,7 +207,7 @@ class LargeObjectTests(LargeObjectTestCase):
         data1 = lo.read()
         # avoid dumping megacraps in the console in case of error
         self.assert_(data == data1,
-            "{!r}... != {!r}...".format(data[:100], data1[:100]))
+            f"{data[:100]!r}... != {data1[:100]!r}...")
 
     def test_seek_tell(self):
         lo = self.conn.lobject()
diff --git a/tests/test_module.py b/tests/test_module.py
index dc96e23..717cf50 100755
--- a/tests/test_module.py
+++ b/tests/test_module.py
@@ -120,7 +120,7 @@ class ConnectTestCase(unittest.TestCase):
 
     def test_int_port_param(self):
         psycopg2.connect(database='sony', port=6543)
-        dsn = " %s " % self.args[0]
+        dsn = f" {self.args[0]} "
         self.assert_(" dbname=sony " in dsn, dsn)
         self.assert_(" port=6543 " in dsn, dsn)
 
@@ -327,12 +327,12 @@ class TestExtensionModule(unittest.TestCase):
         pkgdir = os.path.dirname(psycopg2.__file__)
         pardir = os.path.dirname(pkgdir)
         self.assert_(pardir in sys.path)
-        script = ("""
+        script = f"""
 import sys
-sys.path.remove({!r})
-sys.path.insert(0, {!r})
+sys.path.remove({pardir!r})
+sys.path.insert(0, {pkgdir!r})
 import _psycopg
-""".format(pardir, pkgdir))
+"""
 
         proc = Popen([sys.executable, '-c', script])
         proc.communicate()
diff --git a/tests/test_notify.py b/tests/test_notify.py
index f6c514b..a3586f8 100755
--- a/tests/test_notify.py
+++ b/tests/test_notify.py
@@ -56,7 +56,7 @@ class NotifiesTests(ConnectingTestCase):
         if payload is None:
             payload = ''
         else:
-            payload = ", %r" % payload
+            payload = f", {payload!r}"
 
         script = ("""\
 import time
diff --git a/tests/test_quote.py b/tests/test_quote.py
index 7489b3f..98ec494 100755
--- a/tests/test_quote.py
+++ b/tests/test_quote.py
@@ -98,8 +98,7 @@ class QuotingTestCase(ConnectingTestCase):
         server_encoding = curs.fetchone()[0]
         if server_encoding != "UTF8":
             return self.skipTest(
-                "Unicode test skipped since server encoding is %s"
-                % server_encoding)
+                f"Unicode test skipped since server encoding is {server_encoding}")
 
         data = """some data with \t chars
         to escape into, 'quotes', \u20ac euro sign and \\ a backslash too.
diff --git a/tests/test_replication.py b/tests/test_replication.py
index 657fa60..569ed39 100755
--- a/tests/test_replication.py
+++ b/tests/test_replication.py
@@ -244,9 +244,9 @@ class AsyncReplicationTest(ReplicationTestCase):
 
         def consume(msg):
             # just check the methods
-            "{}: {}".format(cur.io_timestamp, repr(msg))
-            "{}: {}".format(cur.feedback_timestamp, repr(msg))
-            "{}: {}".format(cur.wal_end, repr(msg))
+            f"{cur.io_timestamp}: {repr(msg)}"
+            f"{cur.feedback_timestamp}: {repr(msg)}"
+            f"{cur.wal_end}: {repr(msg)}"
 
             self.msg_count += 1
             if self.msg_count > 3:
diff --git a/tests/test_types_extras.py b/tests/test_types_extras.py
index 942785c..c653020 100755
--- a/tests/test_types_extras.py
+++ b/tests/test_types_extras.py
@@ -711,7 +711,7 @@ class AdaptTypeTestCase(ConnectingTestCase):
     def _create_type(self, name, fields):
         curs = self.conn.cursor()
         try:
-            curs.execute("drop type %s cascade;" % name)
+            curs.execute(f"drop type {name} cascade;")
         except psycopg2.ProgrammingError:
             self.conn.rollback()
 
@@ -1300,14 +1300,14 @@ class RangeCasterTestCase(ConnectingTestCase):
     def test_cast_null(self):
         cur = self.conn.cursor()
         for type in self.builtin_ranges:
-            cur.execute("select NULL::%s" % type)
+            cur.execute(f"select NULL::{type}")
             r = cur.fetchone()[0]
             self.assertEqual(r, None)
 
     def test_cast_empty(self):
         cur = self.conn.cursor()
         for type in self.builtin_ranges:
-            cur.execute("select 'empty'::%s" % type)
+            cur.execute(f"select 'empty'::{type}")
             r = cur.fetchone()[0]
             self.assert_(isinstance(r, Range), type)
             self.assert_(r.isempty)
@@ -1315,7 +1315,7 @@ class RangeCasterTestCase(ConnectingTestCase):
     def test_cast_inf(self):
         cur = self.conn.cursor()
         for type in self.builtin_ranges:
-            cur.execute("select '(,)'::%s" % type)
+            cur.execute(f"select '(,)'::{type}")
             r = cur.fetchone()[0]
             self.assert_(isinstance(r, Range), type)
             self.assert_(not r.isempty)
@@ -1325,7 +1325,7 @@ class RangeCasterTestCase(ConnectingTestCase):
     def test_cast_numbers(self):
         cur = self.conn.cursor()
         for type in ('int4range', 'int8range'):
-            cur.execute("select '(10,20)'::%s" % type)
+            cur.execute(f"select '(10,20)'::{type}")
             r = cur.fetchone()[0]
             self.assert_(isinstance(r, NumericRange))
             self.assert_(not r.isempty)
diff --git a/tests/testconfig.py b/tests/testconfig.py
index 511f1fb..ed6132a 100644
--- a/tests/testconfig.py
+++ b/tests/testconfig.py
@@ -23,15 +23,15 @@ if green:
     psycopg2.extensions.set_wait_callback(wait_callback)
 
 # Construct a DSN to connect to the test database:
-dsn = 'dbname=%s' % dbname
+dsn = f'dbname={dbname}'
 if dbhost is not None:
-    dsn += ' host=%s' % dbhost
+    dsn += f' host={dbhost}'
 if dbport is not None:
-    dsn += ' port=%s' % dbport
+    dsn += f' port={dbport}'
 if dbuser is not None:
-    dsn += ' user=%s' % dbuser
+    dsn += f' user={dbuser}'
 if dbpass is not None:
-    dsn += ' password=%s' % dbpass
+    dsn += f' password={dbpass}'
 
 # Don't run replication tests if REPL_DSN is not set, default to normal DSN if
 # set to empty string.
diff --git a/tests/testutils.py b/tests/testutils.py
index be6098c..007fda2 100644
--- a/tests/testutils.py
+++ b/tests/testutils.py
@@ -100,8 +100,7 @@ class ConnectingTestCase(unittest.TestCase):
             self._conns
         except AttributeError as e:
             raise AttributeError(
-                "%s (did you forget to call ConnectingTestCase.setUp()?)"
-                % e)
+                f"{e} (did you forget to call ConnectingTestCase.setUp()?)")
 
         if 'dsn' in kwargs:
             conninfo = kwargs.pop('dsn')
@@ -134,7 +133,7 @@ class ConnectingTestCase(unittest.TestCase):
             # Otherwise we tried to run some bad operation in the connection
             # (e.g. bug #482) and we'd rather know that.
             if e.pgcode is None:
-                return self.skipTest("replication db not configured: %s" % e)
+                return self.skipTest(f"replication db not configured: {e}")
             else:
                 raise
 
@@ -324,7 +323,7 @@ def skip_after_libpq(*ver):
         v = libpq_version()
         decorator = unittest.skipIf(
             v >= int("%d%02d%02d" % ver),
-            "skipped because libpq %s" % v,
+            f"skipped because libpq {v}",
         )
         return decorator(cls)
     return skip_after_libpq_
@@ -335,8 +334,7 @@ def skip_before_python(*ver):
     def skip_before_python_(cls):
         decorator = unittest.skipIf(
             sys.version_info[:len(ver)] < ver,
-            "skipped because Python %s"
-            % ".".join(map(str, sys.version_info[:len(ver)])),
+            f"skipped because Python {'.'.join(map(str, sys.version_info[:len(ver)]))}",
         )
         return decorator(cls)
     return skip_before_python_
@@ -347,8 +345,7 @@ def skip_from_python(*ver):
     def skip_from_python_(cls):
         decorator = unittest.skipIf(
             sys.version_info[:len(ver)] >= ver,
-            "skipped because Python %s"
-            % ".".join(map(str, sys.version_info[:len(ver)])),
+            f"skipped because Python {'.'.join(map(str, sys.version_info[:len(ver)]))}",
         )
         return decorator(cls)
     return skip_from_python_
@@ -415,7 +412,7 @@ def crdb_version(conn, __crdb_version=[]):
         m = re.search(r"\bv(\d+)\.(\d+)\.(\d+)", sver)
         if not m:
             raise ValueError(
-                "can't parse CockroachDB version from %s" % sver)
+                f"can't parse CockroachDB version from {sver}")
 
         ver = int(m.group(1)) * 10000 + int(m.group(2)) * 100 + int(m.group(3))
         __crdb_version.append(ver)
@@ -439,7 +436,7 @@ def skip_if_crdb(reason, conn=None, version=None):
 
     """
     if not isinstance(reason, str):
-        raise TypeError("reason should be a string, got %r instead" % reason)
+        raise TypeError(f"reason should be a string, got {reason!r} instead")
 
     if conn is not None:
         ver = crdb_version(conn)