Index: testtools-2.4.0/testtools/tests/twistedsupport/test_matchers.py
===================================================================
--- testtools-2.4.0.orig/testtools/tests/twistedsupport/test_matchers.py	2018-04-05 01:27:14.000000000 +0200
+++ testtools-2.4.0/testtools/tests/twistedsupport/test_matchers.py	2020-06-11 11:53:14.265535365 +0200
@@ -205,5 +205,10 @@ class FailureResultTests(NeedsTwistedTes
 
 
 def test_suite():
-    from unittest2 import TestLoader, TestSuite
+    from extras import try_imports
+    try:
+        import unittest2 as unittest
+    except ImportError:
+        import unittest
+    from unittest import TestLoader, TestSuite
     return TestLoader().loadTestsFromName(__name__)
Index: testtools-2.4.0/testtools/tests/twistedsupport/test_deferred.py
===================================================================
--- testtools-2.4.0.orig/testtools/tests/twistedsupport/test_deferred.py	2018-04-05 01:27:14.000000000 +0200
+++ testtools-2.4.0/testtools/tests/twistedsupport/test_deferred.py	2020-06-11 11:55:46.398407913 +0200
@@ -52,5 +52,9 @@ class TestExtractResult(NeedsTwistedTest
 
 
 def test_suite():
-    from unittest2 import TestLoader, TestSuite
+    try:
+        import unittest2 as unittest
+    except ImportError:
+        import unittest
+    from unittest import TestLoader, TestSuite
     return TestLoader().loadTestsFromName(__name__)
Index: testtools-2.4.0/testtools/tests/twistedsupport/test_runtest.py
===================================================================
--- testtools-2.4.0.orig/testtools/tests/twistedsupport/test_runtest.py	2018-04-05 01:27:14.000000000 +0200
+++ testtools-2.4.0/testtools/tests/twistedsupport/test_runtest.py	2020-06-11 11:56:56.142811412 +0200
@@ -1016,7 +1016,11 @@ class TestCaptureTwistedLogs(NeedsTwiste
 
 
 def test_suite():
-    from unittest2 import TestLoader, TestSuite
+    try:
+        import unittest2 as unittest
+    except ImportError:
+        import unittest
+    from unittest import TestLoader, TestSuite
     return TestLoader().loadTestsFromName(__name__)
 
 
Index: testtools-2.4.0/testtools/tests/test_testsuite.py
===================================================================
--- testtools-2.4.0.orig/testtools/tests/test_testsuite.py	2018-04-05 01:27:14.000000000 +0200
+++ testtools-2.4.0/testtools/tests/test_testsuite.py	2020-06-11 11:41:10.153375835 +0200
@@ -5,7 +5,10 @@
 import doctest
 from pprint import pformat
 import unittest
-import unittest2
+try:
+    import unittest2
+except ImportError:
+    unittest2 = None
 
 from extras import try_import
 
@@ -16,6 +19,7 @@ from testtools import (
     PlaceHolder,
     TestByTestResult,
     TestCase,
+    skipUnless
     )
 from testtools.compat import _u
 from testtools.matchers import DocTestMatches, Equals
@@ -214,6 +218,7 @@ TypeError: run() takes ...1 ...argument.
         tests = list(enumerate(iterate_tests(suite)))
         return [(test, _u(str(pos))) for pos, test in tests]
 
+    @skipUnless(unittest2, "requries unittest2")
     def test_setupclass_skip(self):
         # We should support setupclass skipping using cls.skipException.
         # Because folk have used that.
@@ -231,6 +236,7 @@ TypeError: run() takes ...1 ...argument.
         suite.run(result)
         self.assertEqual(['addSkip'], [item[0] for item in log])
 
+    @skipUnless(unittest2, "requries unittest2")
     def test_setupclass_upcall(self):
         # Note that this is kindof-a-case-test, kindof-suite, because
         # setUpClass is linked between them.
Index: testtools-2.4.0/testtools/tests/test_run.py
===================================================================
--- testtools-2.4.0.orig/testtools/tests/test_run.py	2015-11-07 18:27:33.000000000 +0100
+++ testtools-2.4.0/testtools/tests/test_run.py	2020-06-11 11:34:41.815147077 +0200
@@ -10,7 +10,10 @@ from textwrap import dedent
 from extras import try_import
 fixtures = try_import('fixtures')
 testresources = try_import('testresources')
-import unittest2
+try:
+    import unittest2
+except ImportError:
+    unittest2 = None
 
 import testtools
 from testtools import TestCase, run, skipUnless
@@ -191,6 +194,7 @@ class TestRun(TestCase):
 testtools.runexample.TestFoo.test_quux
 """, out.getvalue())
 
+    @skipUnless(unittest2, "requries unittest2")
     def test_run_list_failed_import(self):
         broken = self.useFixture(SampleTestFixture(broken=True))
         out = StringIO()
@@ -337,6 +341,7 @@ OK
 """)))
 
     @skipUnless(fixtures, "fixtures not present")
+    @skipUnless(unittest2, "requries unittest2")
     def test_issue_16662(self):
         # unittest's discover implementation didn't handle load_tests on
         # packages. That is fixed pending commit, but we want to offer it