Move imports to the top of the module across tests

Allows removing many duplicate imports and better follows PEP8
guidelines:

https://www.python.org/dev/peps/pep-0008/#imports

> Imports are always put at the top of the file, just after any module
> comments and docstrings, and before module globals and constants.

15 files changed, 48 insertions, 171 deletions

diff --git a/tests/test_async_keyword.py b/tests/test_async_keyword.py
index 7a2e040..d86fa5e 100755
--- a/tests/test_async_keyword.py
+++ b/tests/test_async_keyword.py
@@ -24,6 +24,7 @@
 # License for more details.
 
 import time
+from select import select
 
 import psycopg2
 from psycopg2 import extras
@@ -205,7 +206,6 @@ class AsyncReplicationTest(ReplicationTestCase):
         self.assertRaises(psycopg2.ProgrammingError, cur.consume_stream, consume)
 
         def process_stream():
-            from select import select
             while True:
                 msg = cur.read_message()
                 if msg:
diff --git a/tests/test_connection.py b/tests/test_connection.py
index 32088e7..1c35e8b 100755
--- a/tests/test_connection.py
+++ b/tests/test_connection.py
@@ -22,18 +22,24 @@
 # FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
 # License for more details.
 
-import re
+import ctypes
+import gc
 import os
+import re
+import subprocess as sp
 import sys
-import time
-import ctypes
 import threading
-import subprocess as sp
+import time
+from collections import deque
 from operator import attrgetter
+from weakref import ref
 
 import psycopg2
 import psycopg2.errorcodes
 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,
@@ -149,8 +155,6 @@ class ConnectionTests(ConnectingTestCase):
 
     @slow
     def test_notices_deque(self):
-        from collections import deque
-
         conn = self.conn
         self.conn.notices = deque()
         cur = conn.cursor()
@@ -255,8 +259,6 @@ class ConnectionTests(ConnectingTestCase):
         conn.close()
 
     def test_weakref(self):
-        from weakref import ref
-        import gc
         conn = psycopg2.connect(dsn)
         w = ref(conn)
         conn.close()
@@ -362,8 +364,6 @@ class ConnectionTests(ConnectingTestCase):
 
 class ParseDsnTestCase(ConnectingTestCase):
     def test_parse_dsn(self):
-        from psycopg2 import ProgrammingError
-
         self.assertEqual(
             ext.parse_dsn('dbname=test user=tester password=secret'),
             dict(user='tester', password='secret', dbname='test'),
@@ -1124,16 +1124,12 @@ class ConnectionTwoPhaseTests(ConnectingTestCase):
             cnn.tpc_rollback(xid)
 
     def test_xid_construction(self):
-        from psycopg2.extensions import Xid
-
         x1 = 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):
-        from psycopg2.extensions import Xid
-
         x2 = Xid.from_string('42_Z3RyaWQ=_YnF1YWw=')
         self.assertEqual(42, x2.format_id)
         self.assertEqual('gtrid', x2.gtrid)
@@ -1145,8 +1141,6 @@ class ConnectionTwoPhaseTests(ConnectingTestCase):
         self.assertEqual(None, x3.bqual)
 
     def test_xid_to_string(self):
-        from psycopg2.extensions import Xid
-
         x1 = Xid.from_string('42_Z3RyaWQ=_YnF1YWw=')
         self.assertEqual(str(x1), '42_Z3RyaWQ=_YnF1YWw=')
 
@@ -1186,7 +1180,6 @@ class ConnectionTwoPhaseTests(ConnectingTestCase):
         self.assertRaises(psycopg2.ProgrammingError, cnn.cancel)
 
     def test_tpc_recover_non_dbapi_connection(self):
-        from psycopg2.extras import RealDictConnection
         cnn = self.connect(connection_factory=RealDictConnection)
         cnn.tpc_begin('dict-connection')
         cnn.tpc_prepare()
diff --git a/tests/test_cursor.py b/tests/test_cursor.py
index 6b5b5f8..675699c 100755
--- a/tests/test_cursor.py
+++ b/tests/test_cursor.py
@@ -28,6 +28,9 @@ import pickle
 import psycopg2
 import psycopg2.extensions
 import unittest
+from datetime import date
+from decimal import Decimal
+from weakref import ref
 from .testutils import (ConnectingTestCase, skip_before_postgres,
     skip_if_no_getrefcount, slow, skip_if_no_superuser,
     skip_if_windows)
@@ -101,8 +104,6 @@ class CursorTests(ConnectingTestCase):
             cur.mogrify(u"SELECT %s;", (snowman,)))
 
     def test_mogrify_decimal_explodes(self):
-        from decimal import Decimal
-
         conn = self.conn
         cur = conn.cursor()
         self.assertEqual(b'SELECT 10.3;',
@@ -143,10 +144,8 @@ class CursorTests(ConnectingTestCase):
         self.assertEqual(42, curs.cast(20, '42'))
         self.assertAlmostEqual(3.14, curs.cast(700, '3.14'))
 
-        from decimal import Decimal
         self.assertEqual(Decimal('123.45'), curs.cast(1700, '123.45'))
 
-        from datetime import date
         self.assertEqual(date(2011, 1, 2), curs.cast(1082, '2011-01-02'))
         self.assertEqual("who am i?", curs.cast(705, 'who am i?'))  # unknown
 
@@ -166,7 +165,6 @@ class CursorTests(ConnectingTestCase):
         self.assertEqual("foofoo", curs2.cast(705, 'foo'))
 
     def test_weakref(self):
-        from weakref import ref
         curs = self.conn.cursor()
         w = ref(curs)
         del curs
diff --git a/tests/test_dates.py b/tests/test_dates.py
index fdc2874..0c1c504 100755
--- a/tests/test_dates.py
+++ b/tests/test_dates.py
@@ -23,7 +23,10 @@
 # License for more details.
 
 import math
+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
@@ -130,7 +133,6 @@ class DatetimeTests(ConnectingTestCase, CommonDatetimeTestsMixin):
         self.assertEqual(value.microsecond, 123456)
 
     def check_time_tz(self, str_offset, offset):
-        from datetime import time, timedelta
         base = time(13, 30, 29)
         base_str = '13:30:29'
 
@@ -161,7 +163,6 @@ class DatetimeTests(ConnectingTestCase, CommonDatetimeTestsMixin):
         self.check_time_tz("-01:15:59", -60 * (60 + 16))
 
     def check_datetime_tz(self, str_offset, offset):
-        from datetime import datetime, timedelta
         base = datetime(2007, 1, 1, 13, 30, 29)
         base_str = '2007-01-01 13:30:29'
 
@@ -229,25 +230,21 @@ class DatetimeTests(ConnectingTestCase, CommonDatetimeTestsMixin):
         self.assertEqual(str(value), '9999-12-31')
 
     def test_adapt_date(self):
-        from datetime import date
         value = self.execute('select (%s)::date::text',
                              [date(2007, 1, 1)])
         self.assertEqual(value, '2007-01-01')
 
     def test_adapt_time(self):
-        from 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 datetime import datetime
         value = self.execute('select (%s)::timestamp::text',
                              [datetime(2007, 1, 1, 13, 30, 29)])
         self.assertEqual(value, '2007-01-01 13:30:29')
 
     def test_adapt_timedelta(self):
-        from datetime import timedelta
         value = self.execute('select extract(epoch from (%s)::interval)',
                              [timedelta(days=42, seconds=45296,
                                         microseconds=123456)])
@@ -256,7 +253,6 @@ class DatetimeTests(ConnectingTestCase, CommonDatetimeTestsMixin):
         self.assertEqual(int(round((value - seconds) * 1000000)), 123456)
 
     def test_adapt_negative_timedelta(self):
-        from datetime import timedelta
         value = self.execute('select extract(epoch from (%s)::interval)',
                              [timedelta(days=-42, seconds=45296,
                                         microseconds=123456)])
@@ -275,17 +271,13 @@ class DatetimeTests(ConnectingTestCase, CommonDatetimeTestsMixin):
         self.assertEqual(type(o1[0]), type(o2[0]))
 
     def test_type_roundtrip_date(self):
-        from datetime import date
         self._test_type_roundtrip(date(2010, 5, 3))
 
     def test_type_roundtrip_datetime(self):
-        from datetime import datetime
         dt = self._test_type_roundtrip(datetime(2010, 5, 3, 10, 20, 30))
         self.assertEqual(None, dt.tzinfo)
 
     def test_type_roundtrip_datetimetz(self):
-        from datetime import datetime
-        import psycopg2.tz
         tz = psycopg2.tz.FixedOffsetTimezone(8 * 60)
         dt1 = datetime(2010, 5, 3, 10, 20, 30, tzinfo=tz)
         dt2 = self._test_type_roundtrip(dt1)
@@ -293,13 +285,10 @@ class DatetimeTests(ConnectingTestCase, CommonDatetimeTestsMixin):
         self.assertEqual(dt1, dt2)
 
     def test_type_roundtrip_time(self):
-        from datetime import time
         tm = self._test_type_roundtrip(time(10, 20, 30))
         self.assertEqual(None, tm.tzinfo)
 
     def test_type_roundtrip_timetz(self):
-        from datetime import time
-        import psycopg2.tz
         tz = psycopg2.tz.FixedOffsetTimezone(8 * 60)
         tm1 = time(10, 20, 30, tzinfo=tz)
         tm2 = self._test_type_roundtrip(tm1)
@@ -307,34 +296,26 @@ class DatetimeTests(ConnectingTestCase, CommonDatetimeTestsMixin):
         self.assertEqual(tm1, tm2)
 
     def test_type_roundtrip_interval(self):
-        from datetime import timedelta
         self._test_type_roundtrip(timedelta(seconds=30))
 
     def test_type_roundtrip_date_array(self):
-        from datetime import date
         self._test_type_roundtrip_array(date(2010, 5, 3))
 
     def test_type_roundtrip_datetime_array(self):
-        from datetime import datetime
         self._test_type_roundtrip_array(datetime(2010, 5, 3, 10, 20, 30))
 
     def test_type_roundtrip_datetimetz_array(self):
-        from datetime import datetime
         self._test_type_roundtrip_array(
             datetime(2010, 5, 3, 10, 20, 30, tzinfo=FixedOffsetTimezone(0)))
 
     def test_type_roundtrip_time_array(self):
-        from datetime import time
         self._test_type_roundtrip_array(time(10, 20, 30))
 
     def test_type_roundtrip_interval_array(self):
-        from datetime import timedelta
         self._test_type_roundtrip_array(timedelta(seconds=30))
 
     @skip_before_postgres(8, 1)
     def test_time_24(self):
-        from datetime import time
-
         t = self.execute("select '24:00'::time;")
         self.assertEqual(t, time(0, 0))
 
@@ -399,8 +380,6 @@ class DatetimeTests(ConnectingTestCase, CommonDatetimeTestsMixin):
         self.assertRaises(OverflowError, f, '00:00:00.100000000000000000')
 
     def test_adapt_infinity_tz(self):
-        from datetime import datetime
-
         t = self.execute("select 'infinity'::timestamp")
         self.assert_(t.tzinfo is None)
         self.assert_(t > datetime(4000, 1, 1))
@@ -425,7 +404,6 @@ class DatetimeTests(ConnectingTestCase, CommonDatetimeTestsMixin):
                 psycopg2.STRING.values, 'WAT', psycopg2.extensions.INTERVAL),
             cur)
 
-        from datetime import timedelta
         for s, v in [
             ('0', timedelta(0)),
             ('1', timedelta(microseconds=1)),
@@ -629,20 +607,17 @@ class FromTicksTestCase(unittest.TestCase):
     # bug "TimestampFromTicks() throws ValueError (2-2.0.14)"
     # reported by Jozsef Szalay on 2010-05-06
     def test_timestamp_value_error_sec_59_99(self):
-        from datetime import datetime
         s = psycopg2.TimestampFromTicks(1273173119.99992)
         self.assertEqual(s.adapted,
             datetime(2010, 5, 6, 14, 11, 59, 999920,
                 tzinfo=FixedOffsetTimezone(-5 * 60)))
 
     def test_date_value_error_sec_59_99(self):
-        from datetime import date
         s = psycopg2.DateFromTicks(1273173119.99992)
         # The returned date is local
         self.assert_(s.adapted in [date(2010, 5, 6), date(2010, 5, 7)])
 
     def test_time_value_error_sec_59_99(self):
-        from datetime import time
         s = psycopg2.TimeFromTicks(1273173119.99992)
         self.assertEqual(s.adapted.replace(hour=0),
             time(0, 11, 59, 999920))
diff --git a/tests/test_errors.py b/tests/test_errors.py
index 4369960..072688e 100755
--- a/tests/test_errors.py
+++ b/tests/test_errors.py
@@ -26,6 +26,9 @@ import unittest
 from .testutils import ConnectingTestCase
 
 import psycopg2
+from psycopg2 import errors
+from psycopg2._psycopg import sqlstate_errors
+from psycopg2.errors import UndefinedTable
 
 
 class ErrorsTests(ConnectingTestCase):
@@ -36,14 +39,12 @@ class ErrorsTests(ConnectingTestCase):
         except psycopg2.Error as exc:
             e = exc
 
-        from psycopg2.errors import UndefinedTable
         self.assert_(isinstance(e, UndefinedTable), type(e))
         self.assert_(isinstance(e, self.conn.ProgrammingError))
 
     def test_exception_class_fallback(self):
         cur = self.conn.cursor()
 
-        from psycopg2._psycopg import sqlstate_errors
         x = sqlstate_errors.pop('42P01')
         try:
             cur.execute("select * from nonexist")
@@ -55,17 +56,12 @@ class ErrorsTests(ConnectingTestCase):
         self.assertEqual(type(e), self.conn.ProgrammingError)
 
     def test_lookup(self):
-        from psycopg2 import errors
-
         self.assertIs(errors.lookup('42P01'), errors.UndefinedTable)
 
         with self.assertRaises(KeyError):
             errors.lookup('XXXXX')
 
     def test_has_base_exceptions(self):
-        import psycopg2
-        from psycopg2 import errors
-
         excs = []
         for n in dir(psycopg2):
             obj = getattr(psycopg2, n)
diff --git a/tests/test_extras_dictcursor.py b/tests/test_extras_dictcursor.py
index c1aa9ae..7eee4cc 100755
--- a/tests/test_extras_dictcursor.py
+++ b/tests/test_extras_dictcursor.py
@@ -16,10 +16,14 @@
 
 import time
 import pickle
+import unittest
 from datetime import timedelta
+
 import psycopg2
+from psycopg2.compat import lru_cache
 import psycopg2.extras
-import unittest
+from psycopg2.extras import NamedTupleConnection, NamedTupleCursor
+
 from .testutils import ConnectingTestCase, skip_before_postgres, \
     skip_before_python, skip_from_python
 
@@ -358,7 +362,6 @@ class ExtrasDictCursorRealTests(_DictCursorBase):
 class NamedTupleCursorTest(ConnectingTestCase):
     def setUp(self):
         ConnectingTestCase.setUp(self)
-        from psycopg2.extras import NamedTupleConnection
 
         self.conn = self.connect(connection_factory=NamedTupleConnection)
         curs = self.conn.cursor()
@@ -495,7 +498,6 @@ class NamedTupleCursorTest(ConnectingTestCase):
 
     def test_minimal_generation(self):
         # Instrument the class to verify it gets called the minimum number of times.
-        from psycopg2.extras import NamedTupleCursor
         f_orig = NamedTupleCursor._make_nt
         calls = [0]
 
@@ -591,9 +593,6 @@ class NamedTupleCursorTest(ConnectingTestCase):
         self.assert_(type(r1) is not type(r2))
 
     def test_max_cache(self):
-        from psycopg2.extras import NamedTupleCursor
-        from psycopg2.compat import lru_cache
-
         old_func = NamedTupleCursor._cached_make_nt
         NamedTupleCursor._cached_make_nt = \
             lru_cache(8)(NamedTupleCursor._do_make_nt)
diff --git a/tests/test_fast_executemany.py b/tests/test_fast_executemany.py
index a7a9a5f..e059744 100755
--- a/tests/test_fast_executemany.py
+++ b/tests/test_fast_executemany.py
@@ -22,6 +22,7 @@ import unittest
 import psycopg2
 import psycopg2.extras
 import psycopg2.extensions as ext
+from psycopg2 import sql
 
 
 class TestPaginate(unittest.TestCase):
@@ -84,7 +85,6 @@ class TestExecuteBatch(FastExecuteTestMixin, testutils.ConnectingTestCase):
         self.assertEqual(cur.fetchall(), [(i, i * 10) for i in range(1000)])
 
     def test_composed(self):
-        from psycopg2 import sql
         cur = self.conn.cursor()
         psycopg2.extras.execute_batch(cur,
             sql.SQL("insert into {0} (id, val) values (%s, %s)")
@@ -181,7 +181,6 @@ class TestExecuteValues(FastExecuteTestMixin, testutils.ConnectingTestCase):
         self.assertEqual(cur.fetchall(), [(i, i * 10) for i in range(1000)])
 
     def test_composed(self):
-        from psycopg2 import sql
         cur = self.conn.cursor()
         psycopg2.extras.execute_values(cur,
             sql.SQL("insert into {0} (id, val) values %s")
diff --git a/tests/test_green.py b/tests/test_green.py
index 424c4f9..0f45efb 100755
--- a/tests/test_green.py
+++ b/tests/test_green.py
@@ -22,10 +22,12 @@
 # FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
 # License for more details.
 
+import select
 import unittest
 import psycopg2
 import psycopg2.extensions
 import psycopg2.extras
+from psycopg2.extensions import POLL_OK, POLL_READ, POLL_WRITE
 
 from .testutils import ConnectingTestCase, skip_before_postgres, slow
 
@@ -131,9 +133,6 @@ class CallbackErrorTestCase(ConnectingTestCase):
 
     def crappy_callback(self, conn):
         """green callback failing after `self.to_error` time it is called"""
-        import select
-        from psycopg2.extensions import POLL_OK, POLL_READ, POLL_WRITE
-
         while True:
             if self.to_error is not None:
                 self.to_error -= 1
diff --git a/tests/test_module.py b/tests/test_module.py
index 41d8d6d..c9b9c6b 100755
--- a/tests/test_module.py
+++ b/tests/test_module.py
@@ -22,9 +22,11 @@
 # FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
 # License for more details.
 
+import gc
 import os
 import sys
 from subprocess import Popen
+from weakref import ref
 
 import unittest
 from .testutils import (skip_before_postgres,
@@ -190,9 +192,6 @@ class ExceptionsTestCase(ConnectingTestCase):
         self.assertEqual(e.diag.severity, 'ERROR')
 
     def test_diagnostics_life(self):
-        import gc
-        from weakref import ref
-
         def tmp():
             cur = self.conn.cursor()
             try:
diff --git a/tests/test_notify.py b/tests/test_notify.py
index 127eb06..576379a 100755
--- a/tests/test_notify.py
+++ b/tests/test_notify.py
@@ -23,9 +23,11 @@
 # License for more details.
 
 import unittest
+from collections import deque
 
 import psycopg2
 from psycopg2 import extensions
+from psycopg2.extensions import Notify
 from .testutils import ConnectingTestCase, slow
 from .testconfig import dsn
 
@@ -163,7 +165,6 @@ conn.close()
 
     @slow
     def test_notify_deque(self):
-        from collections import deque
         self.autocommit(self.conn)
         self.conn.notifies = deque()
         self.listen('foo')
@@ -209,14 +210,12 @@ conn.close()
                 self.assertEqual((n1 != n2), (d1 != d2))
 
     def test_compare_tuple(self):
-        from psycopg2.extensions import Notify
         self.assertEqual((10, 'foo'), Notify(10, 'foo'))
         self.assertEqual((10, 'foo'), Notify(10, 'foo', 'bar'))
         self.assertNotEqual((10, 'foo'), Notify(20, 'foo'))
         self.assertNotEqual((10, 'foo'), Notify(10, 'bar'))
 
     def test_hash(self):
-        from psycopg2.extensions import Notify
         self.assertEqual(hash((10, 'foo')), hash(Notify(10, 'foo')))
         self.assertNotEqual(hash(Notify(10, 'foo', 'bar')),
             hash(Notify(10, 'foo')))
diff --git a/tests/test_quote.py b/tests/test_quote.py
index 4a8db04..fe0b9cd 100755
--- a/tests/test_quote.py
+++ b/tests/test_quote.py
@@ -29,6 +29,7 @@ from .testutils import ConnectingTestCase, unichr
 
 import psycopg2
 import psycopg2.extensions
+from psycopg2.extensions import adapt, quote_ident
 
 
 class QuotingTestCase(ConnectingTestCase):
@@ -194,13 +195,11 @@ class TestQuotedString(ConnectingTestCase):
 
 class TestQuotedIdentifier(ConnectingTestCase):
     def test_identifier(self):
-        from psycopg2.extensions import quote_ident
         self.assertEqual(quote_ident('blah-blah', self.conn), '"blah-blah"')
         self.assertEqual(quote_ident('quote"inside', self.conn), '"quote""inside"')
 
     @testutils.skip_before_postgres(8, 0)
     def test_unicode_ident(self):
-        from psycopg2.extensions import quote_ident
         snowman = u"\u2603"
         quoted = '"' + snowman + '"'
         if sys.version_info[0] < 3:
@@ -211,7 +210,6 @@ class TestQuotedIdentifier(ConnectingTestCase):
 
 class TestStringAdapter(ConnectingTestCase):
     def test_encoding_default(self):
-        from psycopg2.extensions import adapt
         a = adapt("hello")
         self.assertEqual(a.encoding, 'latin1')
         self.assertEqual(a.getquoted(), b"'hello'")
@@ -223,7 +221,6 @@ class TestStringAdapter(ConnectingTestCase):
         # self.assertEqual(adapt(egrave).getquoted(), "'\xe8'")
 
     def test_encoding_error(self):
-        from psycopg2.extensions import adapt
         snowman = u"\u2603"
         a = adapt(snowman)
         self.assertRaises(UnicodeEncodeError, a.getquoted)
@@ -232,7 +229,6 @@ class TestStringAdapter(ConnectingTestCase):
         # Note: this works-ish mostly in case when the standard db connection
         # we test with is utf8, otherwise the encoding chosen by PQescapeString
         # may give bad results.
-        from psycopg2.extensions import adapt
         snowman = u"\u2603"
         a = adapt(snowman)
         a.encoding = 'utf8'
@@ -240,7 +236,6 @@ class TestStringAdapter(ConnectingTestCase):
         self.assertEqual(a.getquoted(), b"'\xe2\x98\x83'")
 
     def test_connection_wins_anyway(self):
-        from psycopg2.extensions import adapt
         snowman = u"\u2603"
         a = adapt(snowman)
         a.encoding = 'latin9'
diff --git a/tests/test_replication.py b/tests/test_replication.py
index 18175b3..7cb4327 100755
--- a/tests/test_replication.py
+++ b/tests/test_replication.py
@@ -22,7 +22,10 @@
 # FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
 # License for more details.
 
+from select import select
+
 import psycopg2
+from psycopg2 import sql
 from psycopg2.extras import (
     PhysicalReplicationConnection, LogicalReplicationConnection, StopReplication)
 
@@ -141,7 +144,6 @@ class ReplicationTest(ReplicationTestCase):
     @skip_before_postgres(9, 4)  # slots require 9.4
     @skip_repl_if_green
     def test_start_replication_expert_sql(self):
-        from psycopg2 import sql
         conn = self.repl_connect(connection_factory=LogicalReplicationConnection)
         if conn is None:
             return
@@ -252,7 +254,6 @@ class AsyncReplicationTest(ReplicationTestCase):
         self.assertRaises(psycopg2.ProgrammingError, cur.consume_stream, consume)
 
         def process_stream():
-            from select import select
             while True:
                 msg = cur.read_message()
                 if msg:
diff --git a/tests/test_types_basic.py b/tests/test_types_basic.py
index 9f1fd6d..ff1dba0 100755
--- a/tests/test_types_basic.py
+++ b/tests/test_types_basic.py
@@ -33,6 +33,7 @@ from .testutils import ConnectingTestCase, long
 
 import psycopg2
 from psycopg2.compat import text_type
+from psycopg2.extensions import AsIs, adapt, register_adapter
 
 
 class TypesBasicTests(ConnectingTestCase):
@@ -424,8 +425,6 @@ class TypesBasicTests(ConnectingTestCase):
 
 class AdaptSubclassTest(unittest.TestCase):
     def test_adapt_subtype(self):
-        from psycopg2.extensions import adapt
-
         class Sub(str):
             pass
         s1 = "hel'lo"
@@ -433,8 +432,6 @@ class AdaptSubclassTest(unittest.TestCase):
         self.assertEqual(adapt(s1).getquoted(), adapt(s2).getquoted())
 
     def test_adapt_most_specific(self):
-        from psycopg2.extensions import adapt, register_adapter, AsIs
-
         class A(object):
             pass
 
@@ -454,8 +451,6 @@ class AdaptSubclassTest(unittest.TestCase):
 
     @testutils.skip_from_python(3)
     def test_no_mro_no_joy(self):
-        from psycopg2.extensions import adapt, register_adapter, AsIs
-
         class A:
             pass
 
@@ -470,8 +465,6 @@ class AdaptSubclassTest(unittest.TestCase):
 
     @testutils.skip_before_python(3)
     def test_adapt_subtype_3(self):
-        from psycopg2.extensions import adapt, register_adapter, AsIs
-
         class A:
             pass
 
diff --git a/tests/test_types_extras.py b/tests/test_types_extras.py
index 2b99678..a10d476 100755
--- a/tests/test_types_extras.py
+++ b/tests/test_types_extras.py
@@ -29,6 +29,13 @@ from .testutils import (skip_if_no_uuid, skip_before_postgres,
 import psycopg2
 import psycopg2.extras
 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,
+    register_composite, register_hstore, register_range,
+)
+from psycopg2.tz import FixedOffsetTimezone
 
 
 class TypesExtrasTests(ConnectingTestCase):
@@ -94,7 +101,6 @@ class TypesExtrasTests(ConnectingTestCase):
         self.failUnless(s is None)
 
     def test_inet_conform(self):
-        from psycopg2.extras import Inet
         i = Inet("192.168.1.0/24")
         a = psycopg2.extensions.adapt(i)
         a.prepare(self.conn)
@@ -126,7 +132,6 @@ class TypesExtrasTests(ConnectingTestCase):
 def skip_if_no_hstore(f):
     @wraps(f)
     def skip_if_no_hstore_(self):
-        from psycopg2.extras import HstoreAdapter
         oids = HstoreAdapter.get_oids(self.conn)
         if oids is None or not oids[0]:
             return self.skipTest("hstore not available in test database")
@@ -140,8 +145,6 @@ class HstoreTestCase(ConnectingTestCase):
         if self.conn.info.server_version >= 90000:
             return self.skipTest("skipping dict adaptation with PG pre-9 syntax")
 
-        from psycopg2.extras import HstoreAdapter
-
         o = {'a': '1', 'b': "'", 'c': None}
         if self.conn.encoding == 'UTF8':
             o['d'] = u'\xe0'
@@ -166,8 +169,6 @@ class HstoreTestCase(ConnectingTestCase):
         if self.conn.info.server_version < 90000:
             return self.skipTest("skipping dict adaptation with PG 9 syntax")
 
-        from psycopg2.extras import HstoreAdapter
-
         o = {'a': '1', 'b': "'", 'c': None}
         if self.conn.encoding == 'UTF8':
             o['d'] = u'\xe0'
@@ -197,8 +198,6 @@ class HstoreTestCase(ConnectingTestCase):
             self.assertQuotedEqual(ii[3][1], b"'" + encc + b"'")
 
     def test_parse(self):
-        from psycopg2.extras import HstoreAdapter
-
         def ok(s, d):
             self.assertEqual(HstoreAdapter.parse(s, None), d)
 
@@ -228,8 +227,6 @@ class HstoreTestCase(ConnectingTestCase):
 
     @skip_if_no_hstore
     def test_register_conn(self):
-        from psycopg2.extras import register_hstore
-
         register_hstore(self.conn)
         cur = self.conn.cursor()
         cur.execute("select null::hstore, ''::hstore, 'a => b'::hstore")
@@ -240,8 +237,6 @@ class HstoreTestCase(ConnectingTestCase):
 
     @skip_if_no_hstore
     def test_register_curs(self):
-        from psycopg2.extras import register_hstore
-
         cur = self.conn.cursor()
         register_hstore(cur)
         cur.execute("select null::hstore, ''::hstore, 'a => b'::hstore")
@@ -253,8 +248,6 @@ class HstoreTestCase(ConnectingTestCase):
     @skip_if_no_hstore
     @skip_from_python(3)
     def test_register_unicode(self):
-        from psycopg2.extras import register_hstore
-
         register_hstore(self.conn, unicode=True)
         cur = self.conn.cursor()
         cur.execute("select null::hstore, ''::hstore, 'a => b'::hstore")
@@ -267,8 +260,6 @@ class HstoreTestCase(ConnectingTestCase):
 
     @skip_if_no_hstore
     def test_register_globally(self):
-        from psycopg2.extras import register_hstore, HstoreAdapter
-
         oids = HstoreAdapter.get_oids(self.conn)
         try:
             register_hstore(self.conn, globally=True)
@@ -291,7 +282,6 @@ class HstoreTestCase(ConnectingTestCase):
 
     @skip_if_no_hstore
     def test_roundtrip(self):
-        from psycopg2.extras import register_hstore
         register_hstore(self.conn)
         cur = self.conn.cursor()
 
@@ -322,7 +312,6 @@ class HstoreTestCase(ConnectingTestCase):
     @skip_if_no_hstore
     @skip_from_python(3)
     def test_roundtrip_unicode(self):
-        from psycopg2.extras import register_hstore
         register_hstore(self.conn, unicode=True)
         cur = self.conn.cursor()
 
@@ -351,7 +340,6 @@ class HstoreTestCase(ConnectingTestCase):
 
         # Note: None as conn_or_cursor is just for testing: not public
         # interface and it may break in future.
-        from psycopg2.extras import register_hstore
         register_hstore(None, globally=True, oid=oid)
         try:
             cur.execute("select null::hstore, ''::hstore, 'a => b'::hstore")
@@ -366,7 +354,6 @@ class HstoreTestCase(ConnectingTestCase):
     @skip_if_no_hstore
     @skip_before_postgres(8, 3)
     def test_roundtrip_array(self):
-        from psycopg2.extras import register_hstore
         register_hstore(self.conn)
 
         ds = [{}, {'a': 'b', 'c': None}]
@@ -392,7 +379,6 @@ class HstoreTestCase(ConnectingTestCase):
     @skip_if_no_hstore
     @skip_before_postgres(8, 3)
     def test_array_cast(self):
-        from psycopg2.extras import register_hstore
         register_hstore(self.conn)
         cur = self.conn.cursor()
         cur.execute("select array['a=>1'::hstore, 'b=>2'::hstore];")
@@ -405,7 +391,6 @@ class HstoreTestCase(ConnectingTestCase):
         cur.execute("select 'hstore'::regtype::oid, 'hstore[]'::regtype::oid")
         oid, aoid = cur.fetchone()
 
-        from psycopg2.extras import register_hstore
         register_hstore(None, globally=True, oid=oid, array_oid=aoid)
         try:
             cur.execute("""
@@ -423,9 +408,6 @@ class HstoreTestCase(ConnectingTestCase):
 
     @skip_if_no_hstore
     def test_non_dbapi_connection(self):
-        from psycopg2.extras import RealDictConnection
-        from psycopg2.extras import register_hstore
-
         conn = self.connect(connection_factory=RealDictConnection)
         try:
             register_hstore(conn)
@@ -492,8 +474,6 @@ class AdaptTypeTestCase(ConnectingTestCase):
             ext.register_adapter(type(None), orig_adapter)
 
     def test_tokenization(self):
-        from psycopg2.extras import CompositeCaster
-
         def ok(s, v):
             self.assertEqual(CompositeCaster.tokenize(s), v)
 
@@ -690,7 +670,6 @@ class AdaptTypeTestCase(ConnectingTestCase):
     @skip_if_no_composite
     def test_wrong_schema(self):
         oid = self._create_type("type_ii", [("a", "integer"), ("b", "integer")])
-        from psycopg2.extras import CompositeCaster
         c = CompositeCaster('type_ii', oid, [('a', 23), ('b', 23), ('c', 23)])
         curs = self.conn.cursor()
         psycopg2.extensions.register_type(c.typecaster, curs)
@@ -745,8 +724,6 @@ class AdaptTypeTestCase(ConnectingTestCase):
 
     @skip_if_no_composite
     def test_non_dbapi_connection(self):
-        from psycopg2.extras import RealDictConnection
-        from psycopg2.extras import register_composite
         self._create_type("type_ii", [("a", "integer"), ("b", "integer")])
 
         conn = self.connect(connection_factory=RealDictConnection)
@@ -772,8 +749,6 @@ class AdaptTypeTestCase(ConnectingTestCase):
         oid = self._create_type("type_isd",
             [('anint', 'integer'), ('astring', 'text'), ('adate', 'date')])
 
-        from psycopg2.extras import register_composite, CompositeCaster
-
         class DictComposite(CompositeCaster):
             def make(self, values):
                 return dict(zip(self.attnames, values))
@@ -832,8 +807,6 @@ def skip_if_no_json_type(f):
 
 class JsonTestCase(ConnectingTestCase):
     def test_adapt(self):
-        from psycopg2.extras import json, Json
-
         objs = [None, "te'xt", 123, 123.45,
             u'\xe0\u20ac', ['a', 100], {'a': 100}]
 
@@ -843,8 +816,6 @@ class JsonTestCase(ConnectingTestCase):
                 psycopg2.extensions.QuotedString(json.dumps(obj)).getquoted())
 
     def test_adapt_dumps(self):
-        from psycopg2.extras import json, Json
-
         class DecimalEncoder(json.JSONEncoder):
             def default(self, obj):
                 if isinstance(obj, Decimal):
@@ -860,8 +831,6 @@ class JsonTestCase(ConnectingTestCase):
             b"'123.45'")
 
     def test_adapt_subclass(self):
-        from psycopg2.extras import json, Json
-
         class DecimalEncoder(json.JSONEncoder):
             def default(self, obj):
                 if isinstance(obj, Decimal):
@@ -877,7 +846,6 @@ class JsonTestCase(ConnectingTestCase):
         self.assertQuotedEqual(curs.mogrify("%s", (MyJson(obj),)), b"'123.45'")
 
     def test_register_on_dict(self):
-        from psycopg2.extras import Json
         psycopg2.extensions.register_adapter(dict, Json)
 
         try:
@@ -953,7 +921,6 @@ class JsonTestCase(ConnectingTestCase):
 
     @skip_if_no_json_type
     def test_no_conn_curs(self):
-        from psycopg2._json import _get_json_oids
         oid, array_oid = _get_json_oids(self.conn)
 
         old = psycopg2.extensions.string_types.get(114)
@@ -1141,7 +1108,6 @@ class JsonbTestCase(ConnectingTestCase):
 
 class RangeTestCase(unittest.TestCase):
     def test_noparam(self):
-        from psycopg2.extras import Range
         r = Range()
 
         self.assert_(not r.isempty)
@@ -1153,7 +1119,6 @@ class RangeTestCase(unittest.TestCase):
         self.assert_(not r.upper_inc)
 
     def test_empty(self):
-        from psycopg2.extras import Range
         r = Range(empty=True)
 
         self.assert_(r.isempty)
@@ -1165,7 +1130,6 @@ class RangeTestCase(unittest.TestCase):
         self.assert_(not r.upper_inc)
 
     def test_nobounds(self):
-        from psycopg2.extras import Range
         r = Range(10, 20)
         self.assertEqual(r.lower, 10)
         self.assertEqual(r.upper, 20)
@@ -1176,7 +1140,6 @@ class RangeTestCase(unittest.TestCase):
         self.assert_(not r.upper_inc)
 
     def test_bounds(self):
-        from psycopg2.extras import Range
         for bounds, lower_inc, upper_inc in [
                 ('[)', True, False),
                 ('(]', False, True),
@@ -1192,7 +1155,6 @@ class RangeTestCase(unittest.TestCase):
             self.assertEqual(r.upper_inc, upper_inc)
 
     def test_keywords(self):
-        from psycopg2.extras import Range
         r = Range(upper=20)
         self.assertEqual(r.lower, None)
         self.assertEqual(r.upper, 20)
@@ -1212,12 +1174,10 @@ class RangeTestCase(unittest.TestCase):
         self.assert_(not r.upper_inc)
 
     def test_bad_bounds(self):
-        from psycopg2.extras import Range
         self.assertRaises(ValueError, Range, bounds='(')
         self.assertRaises(ValueError, Range, bounds='[}')
 
     def test_in(self):
-        from psycopg2.extras import Range
         r = Range(empty=True)
         self.assert_(10 not in r)
 
@@ -1269,7 +1229,6 @@ class RangeTestCase(unittest.TestCase):
         self.assert_(21 not in r)
 
     def test_nonzero(self):
-        from psycopg2.extras import Range
         self.assert_(Range())
         self.assert_(Range(10, 20))
         self.assert_(not Range(empty=True))
@@ -1279,7 +1238,6 @@ class RangeTestCase(unittest.TestCase):
             self.assert_(r1 == r2)
             self.assert_(hash(r1) == hash(r2))
 
-        from psycopg2.extras import Range
         assert_equal(Range(empty=True), Range(empty=True))
         assert_equal(Range(), Range())
         assert_equal(Range(10, None), Range(10, None))
@@ -1296,12 +1254,9 @@ class RangeTestCase(unittest.TestCase):
         assert_not_equal(Range(10, 20, '[)'), Range(10, 20, '[]'))
 
     def test_eq_wrong_type(self):
-        from psycopg2.extras import Range
         self.assertNotEqual(Range(10, 20), ())
 
     def test_eq_subclass(self):
-        from psycopg2.extras import Range, NumericRange
-
         class IntRange(NumericRange):
             pass
 
@@ -1316,7 +1271,6 @@ class RangeTestCase(unittest.TestCase):
     # and consistent.
 
     def test_lt_ordering(self):
-        from psycopg2.extras import Range
         self.assert_(Range(empty=True) < Range(0, 4))
         self.assert_(not Range(1, 2) < Range(0, 4))
         self.assert_(Range(0, 4) < Range(1, 2))
@@ -1332,7 +1286,6 @@ class RangeTestCase(unittest.TestCase):
             self.assert_(not Range(1, 2) < 1)
 
     def test_gt_ordering(self):
-        from psycopg2.extras import Range
         self.assert_(not Range(empty=True) > Range(0, 4))
         self.assert_(Range(1, 2) > Range(0, 4))
         self.assert_(not Range(0, 4) > Range(1, 2))
@@ -1348,7 +1301,6 @@ class RangeTestCase(unittest.TestCase):
             self.assert_(Range(1, 2) > 1)
 
     def test_le_ordering(self):
-        from psycopg2.extras import Range
         self.assert_(Range(empty=True) <= Range(0, 4))
         self.assert_(not Range(1, 2) <= Range(0, 4))
         self.assert_(Range(0, 4) <= Range(1, 2))
@@ -1364,7 +1316,6 @@ class RangeTestCase(unittest.TestCase):
             self.assert_(not Range(1, 2) <= 1)
 
     def test_ge_ordering(self):
-        from psycopg2.extras import Range
         self.assert_(not Range(empty=True) >= Range(0, 4))
         self.assert_(Range(1, 2) >= Range(0, 4))
         self.assert_(not Range(0, 4) >= Range(1, 2))
@@ -1380,8 +1331,6 @@ class RangeTestCase(unittest.TestCase):
             self.assert_(Range(1, 2) >= 1)
 
     def test_pickling(self):
-        from psycopg2.extras import Range
-
         r = Range(0, 4)
         self.assertEqual(loads(dumps(r)), r)
 
@@ -1392,7 +1341,6 @@ class RangeTestCase(unittest.TestCase):
         Using ``repr`` for all string conversions can be very unreadable for
         longer types like ``DateTimeTZRange``.
         '''
-        from psycopg2.extras import Range
 
         # Using the "u" prefix to make sure we have the proper return types in
         # Python2
@@ -1420,9 +1368,7 @@ class RangeTestCase(unittest.TestCase):
         Date-Time ranges should return a human-readable string as well on
         string conversion.
         '''
-        from psycopg2.extras import DateTimeTZRange
-        from datetime import datetime
-        from psycopg2.tz import FixedOffsetTimezone
+
         converter = unicode if sys.version_info < (3, 0) else str
         tz = FixedOffsetTimezone(-5 * 60, "EST")
         r = DateTimeTZRange(datetime(2010, 1, 1, tzinfo=tz),
@@ -1446,7 +1392,6 @@ class RangeCasterTestCase(ConnectingTestCase):
             self.assertEqual(r, None)
 
     def test_cast_empty(self):
-        from psycopg2.extras import Range
         cur = self.conn.cursor()
         for type in self.builtin_ranges:
             cur.execute("select 'empty'::%s" % type)
@@ -1455,7 +1400,6 @@ class RangeCasterTestCase(ConnectingTestCase):
             self.assert_(r.isempty)
 
     def test_cast_inf(self):
-        from psycopg2.extras import Range
         cur = self.conn.cursor()
         for type in self.builtin_ranges:
             cur.execute("select '(,)'::%s" % type)
@@ -1466,7 +1410,6 @@ class RangeCasterTestCase(ConnectingTestCase):
             self.assert_(r.upper_inf)
 
     def test_cast_numbers(self):
-        from psycopg2.extras import NumericRange
         cur = self.conn.cursor()
         for type in ('int4range', 'int8range'):
             cur.execute("select '(10,20)'::%s" % type)
@@ -1492,7 +1435,6 @@ class RangeCasterTestCase(ConnectingTestCase):
         self.assert_(not r.upper_inc)
 
     def test_cast_date(self):
-        from psycopg2.extras import DateRange
         cur = self.conn.cursor()
         cur.execute("select '(2000-01-01,2012-12-31)'::daterange")
         r = cur.fetchone()[0]
@@ -1506,7 +1448,6 @@ class RangeCasterTestCase(ConnectingTestCase):
         self.assert_(not r.upper_inc)
 
     def test_cast_timestamp(self):
-        from psycopg2.extras import DateTimeRange
         cur = self.conn.cursor()
         ts1 = datetime(2000, 1, 1)
         ts2 = datetime(2000, 12, 31, 23, 59, 59, 999)
@@ -1522,8 +1463,6 @@ class RangeCasterTestCase(ConnectingTestCase):
         self.assert_(not r.upper_inc)
 
     def test_cast_timestamptz(self):
-        from psycopg2.extras import DateTimeTZRange
-        from psycopg2.tz import FixedOffsetTimezone
         cur = self.conn.cursor()
         ts1 = datetime(2000, 1, 1, tzinfo=FixedOffsetTimezone(600))
         ts2 = datetime(2000, 12, 31, 23, 59, 59, 999,
@@ -1540,7 +1479,6 @@ class RangeCasterTestCase(ConnectingTestCase):
         self.assert_(r.upper_inc)
 
     def test_adapt_number_range(self):
-        from psycopg2.extras import NumericRange
         cur = self.conn.cursor()
 
         r = NumericRange(empty=True)
@@ -1568,7 +1506,6 @@ class RangeCasterTestCase(ConnectingTestCase):
         self.assert_(r1.upper_inc)
 
     def test_adapt_numeric_range(self):
-        from psycopg2.extras import NumericRange
         cur = self.conn.cursor()
 
         r = NumericRange(empty=True)
@@ -1596,8 +1533,6 @@ class RangeCasterTestCase(ConnectingTestCase):
         self.assert_(r1.upper_inc)
 
     def test_adapt_date_range(self):
-        from psycopg2.extras import DateRange, DateTimeRange, DateTimeTZRange
-        from psycopg2.tz import FixedOffsetTimezone
         cur = self.conn.cursor()
 
         d1 = date(2012, 1, 1)
@@ -1630,7 +1565,6 @@ class RangeCasterTestCase(ConnectingTestCase):
         self.assert_(r1.upper_inc)
 
     def test_register_range_adapter(self):
-        from psycopg2.extras import Range, register_range
         cur = self.conn.cursor()
         cur.execute("create type textrange as range (subtype=text)")
         rc = register_range('textrange', 'TextRange', cur)
@@ -1660,7 +1594,6 @@ class RangeCasterTestCase(ConnectingTestCase):
         del ext.adapters[rc.range, ext.ISQLQuote]
 
     def test_range_escaping(self):
-        from psycopg2.extras import register_range
         cur = self.conn.cursor()
         cur.execute("create type textrange as range (subtype=text)")
         rc = register_range('textrange', 'TextRange', cur)
@@ -1714,7 +1647,6 @@ class RangeCasterTestCase(ConnectingTestCase):
         del ext.adapters[TextRange, ext.ISQLQuote]
 
     def test_range_not_found(self):
-        from psycopg2.extras import register_range
         cur = self.conn.cursor()
         self.assertRaises(psycopg2.ProgrammingError,
             register_range, 'nosuchrange', 'FailRange', cur)
@@ -1728,7 +1660,6 @@ class RangeCasterTestCase(ConnectingTestCase):
         cur.execute("create type rs.r3 as range (subtype=text)")
         cur.execute("savepoint x")
 
-        from psycopg2.extras import register_range
         ra1 = register_range('r1', 'r1', cur)
         ra2 = register_range('r2', 'r2', cur)
         rars2 = register_range('rs.r2', 'r2', cur)
diff --git a/tests/testutils.py b/tests/testutils.py
index 24e52f1..8dab1b6 100644
--- a/tests/testutils.py
+++ b/tests/testutils.py
@@ -33,8 +33,11 @@ import unittest
 from functools import wraps
 from ctypes.util import find_library
 from .testconfig import dsn, repl_dsn
+from psycopg2 import ProgrammingError
 from psycopg2.compat import text_type
 
+from .testconfig import green
+
 # Python 2/3 compatibility
 
 if sys.version_info[0] == 2:
@@ -241,7 +244,6 @@ def skip_if_tpc_disabled(f):
     """Skip a test if the server has tpc support disabled."""
     @wraps(f)
     def skip_if_tpc_disabled_(self):
-        from psycopg2 import ProgrammingError
         cnn = self.connect()
         cur = cnn.cursor()
         try:
@@ -368,7 +370,6 @@ def skip_if_no_superuser(f):
     """Skip a test if the database user running the test is not a superuser"""
     @wraps(f)
     def skip_if_no_superuser_(self):
-        from psycopg2 import ProgrammingError
         try:
             return f(self)
         except ProgrammingError as e:
@@ -383,7 +384,6 @@ def skip_if_no_superuser(f):
 
 def skip_if_green(reason):
     def skip_if_green_(cls):
-        from .testconfig import green
         decorator = unittest.skipIf(green, reason)
         return decorator(cls)
     return skip_if_green_