[Cython] Use unittest2 when necessary to support Python 2.6

interfaces/cython/cantera/test/test_func1.py

@@ -1,8 +1,8 @@
-import unittest
 import numpy as np
 
 import cantera as ct
 from . import utilities
+from .utilities import unittest
 
 class TestFunc1(utilities.CanteraTest):
     def test_function(self):

interfaces/cython/cantera/test/test_reactor.py

@@ -1,5 +1,5 @@
 import numpy as np
-import unittest
+from .utilities import unittest
 import re
 
 import cantera as ct

interfaces/cython/cantera/test/test_thermo.py

@@ -1,4 +1,4 @@
-import unittest
+from .utilities import unittest
 import numpy as np
 
 import cantera as ct

interfaces/cython/cantera/test/test_transport.py

@@ -1,4 +1,4 @@
-import unittest
+from .utilities import unittest
 import numpy as np
 
 import cantera as ct

interfaces/cython/cantera/test/utilities.py

@@ -1,5 +1,13 @@
 import numpy as np
-import unittest
+import sys
+
+if sys.version_info[:2] < (2,7):
+    # unittest2 is a backport of the new features added to the
+    # unittest testing framework in Python 2.7. See
+    # https://pypi.python.org/pypi/unittest2
+    import unittest2 as unittest
+else:
+    import unittest
 
 
 class CanteraTest(unittest.TestCase):

test/python/runCythonTests.py

@@ -15,7 +15,7 @@ if sys.version_info[0] == 3:
 else:
     sys.path.insert(0, os.sep.join(cantera_root + ['build', 'python2']))
 
-import unittest
+from cantera.test.utilities import unittest
 import cantera
 
 if __name__ == '__main__':