Add test highlighting urllib3 missing HTTPMessage import from http.client (issue #159)

Author: edschofield

tests/test_future/test_imports_httplib.py

@@ -0,0 +1,25 @@
+from __future__ import absolute_import, print_function
+import sys
+
+from future.utils import PY2
+from future.tests.base import unittest
+
+
+class ImportHttplibTest(unittest.TestCase):
+    def test_issue_159(self):
+        """
+        The latest version of urllib3 (as of 2015-07-25)
+        uses http.client.HTTPMessage, which isn't normally
+        exported on Py2 through __all__ in httplib.py.
+        """
+        from http.client import HTTPMessage
+        if PY2:
+            import mimetools
+            assert issubclass(HTTPMessage, mimetools.Message)
+        else:
+            import email.message
+            assert issubclass(HTTPMessage, email.message.Message)
+
+
+if __name__ == '__main__':
+    unittest.main()