Issue 7780. Adding a test for unittest test discovery from a dotted path.

Lib/unittest/test/test_discovery.py

@@ -341,5 +341,22 @@ class TestDiscovery(unittest.TestCase):
         self.assertEqual(sys.path[0], full_path)
 
 
+    def test_discovery_from_dotted_path(self):
+        loader = unittest.TestLoader()
+
+        tests = [self]
+        expectedPath = os.path.abspath(os.path.dirname(unittest.test.__file__))
+
+        self.wasRun = False
+        def _find_tests(start_dir, pattern):
+            self.wasRun = True
+            self.assertEqual(start_dir, expectedPath)
+            return tests
+        loader._find_tests = _find_tests
+        suite = loader.discover('unittest.test')
+        self.assertTrue(self.wasRun)
+        self.assertEqual(suite._tests, tests)
+
+
 if __name__ == '__main__':
     unittest.main()