These should have been committed over a week ago.

flake8/tests/test_engine.py

@@ -1,9 +1,26 @@
-from flake8 import engine
+from flake8 import engine, util, __version__
+import pep8
 import unittest
 import mock
 
 
 class TestEngine(unittest.TestCase):
+    def setUp(self):
+        self.patches = {}
+
+    def tearDown(self):
+        assert len(self.patches.items()) == 0
+
+    def start_patch(self, patch):
+        self.patches[patch] = mock.patch(patch)
+        return self.patches[patch].start()
+
+    def stop_patches(self):
+        patches = self.patches.copy()
+        for k, v in patches.items():
+            v.stop()
+            del(self.patches[k])
+
     def test_get_style_guide(self):
         with mock.patch('flake8.engine._register_extensions') as reg_ext:
             reg_ext.return_value = ([], [], [])
@@ -19,3 +36,46 @@ class TestEngine(unittest.TestCase):
                 engine.get_style_guide(foo='bar')
                 get_parser.assert_called_once_with()
             StyleGuide.assert_called_once_with(**{'parser': m, 'foo': 'bar'})
+
+    def test_register_extensions(self):
+        with mock.patch('pep8.register_check') as register_check:
+            registered_extensions = engine._register_extensions()
+            self.assertTrue(isinstance(registered_extensions[0], util.OrderedSet))
+            self.assertTrue(len(registered_extensions[0]) > 0)
+            for i in registered_extensions[1:]:
+                self.assertTrue(isinstance(i, list))
+            register_check.assert_called()
+
+    def test_get_parser(self):
+        # setup
+        re = self.start_patch('flake8.engine._register_extensions')
+        gpv = self.start_patch('flake8.engine.get_python_version')
+        pgp = self.start_patch('pep8.get_parser')
+        m = mock.Mock()
+        re.return_value = ([('pyflakes', '0.7'), ('mccabe', '0.2')], [], [])
+        gpv.return_value = 'Python Version'
+        pgp.return_value = m
+        # actual call we're testing
+        parser, hooks = engine.get_parser()
+        # assertions
+        re.assert_called()
+        gpv.assert_called()
+        pgp.assert_called_once_with(
+            'flake8',
+            '%s (pyflakes: 0.7, mccabe: 0.2) Python Version' % __version__
+            )
+        m.remove_option.assert_called()
+        m.add_option.assert_called()
+        self.assertEqual(parser, m)
+        self.assertEqual(hooks, [])
+        # clean-up
+        self.stop_patches()
+
+    def test_get_python_version(self):
+        self.assertTrue('on' in engine.get_python_version())
+        # Silly test but it will provide 100% test coverage
+        # Also we can never be sure (without reconstructing the string
+        # ourselves) what system we may be testing on.
+
+if __name__ == '__main__':
+    unittest.main()

setup.py

@@ -52,6 +52,6 @@ setup(
         "Topic :: Software Development :: Libraries :: Python Modules",
         "Topic :: Software Development :: Quality Assurance",
     ],
-    tests_require=['nose'],
+    tests_require=['nose', 'mock'],
     test_suite='nose.collector',
 )