Remove usages of unittest2

Refs #179

tests/check_astunparse.py

@@ -1,9 +1,6 @@
 import ast
 
-try:
-    import unittest2 as unittest
-except ImportError:
-    import unittest
+import unittest
 
 from . import test_code_gen
 

tests/test_code_gen.py

@@ -12,11 +12,7 @@
 import math
 import sys
 import textwrap
-
-try:
-    import unittest2 as unittest
-except ImportError:
-    import unittest
+import unittest
 
 import astor
 

tests/test_misc.py

@@ -1,10 +1,7 @@
 import ast
 import sys
+import unittest
 import warnings
-try:
-    import unittest2 as unittest
-except ImportError:
-    import unittest
 
 import astor
 

tests/test_optional.py

@@ -10,31 +10,25 @@
 
 """
 
-try:
-    import unittest2 as unittest
-except ImportError:
-    import unittest
+import unittest
 
-try:
-    from test_code_gen import Comparisons
-except ImportError:
-    from .test_code_gen import Comparisons
+from .test_code_gen import Comparisons
 
 try:
     from astunparse_common import AstunparseCommonTestCase
 except ImportError:
-    AstunparseCommonTestCase = None
+    AstunparseCommonTestCase = object
+
+
+@unittest.skipIf(AstunparseCommonTestCase is object, "requires astunparse")
+class UnparseTestCase(unittest.TestCase, Comparisons, AstunparseCommonTestCase):
 
-if AstunparseCommonTestCase is not None:
+    def check_roundtrip(self, code1, mode=None):
+        self.assertAstRoundtrips(code1)
 
-    class UnparseTestCase(AstunparseCommonTestCase, unittest.TestCase,
-                          Comparisons):
-
-        def check_roundtrip(self, code1, mode=None):
-            self.assertAstRoundtrips(code1)
+    def test_files(self):
+        """ Don't bother -- we do this manually and more thoroughly """
 
-        def test_files(self):
-            """ Don't bother -- we do this manually and more thoroughly """
 
 if __name__ == '__main__':
     unittest.main()

tests/test_rtrip.py

@@ -7,11 +7,7 @@
 """
 
 import os
-
-try:
-    import unittest2 as unittest
-except ImportError:
-    import unittest
+import unittest
 
 import astor.rtrip