Issue 7911: unittest.TestCase.longMessage defaults to True for improved failure messages by default

Lib/unittest/case.py

@@ -245,7 +245,7 @@ class TestCase(object):
     # objects used in assert methods) will be printed on failure in *addition*
     # to any explicit message passed.
 
-    longMessage = False
+    longMessage = True
 
     # This attribute sets the maximum length of a diff in failure messages
     # by assert methods using difflib. It is looked up as an instance attribute

Lib/unittest/test/test_assertions.py

@@ -127,7 +127,7 @@ class TestLongMessage(unittest.TestCase):
         self.testableFalse = TestableTestFalse('testTest')
 
     def testDefault(self):
-        self.assertFalse(unittest.TestCase.longMessage)
+        self.assertTrue(unittest.TestCase.longMessage)
 
     def test_formatMsg(self):
         self.assertEqual(self.testableFalse._formatMessage(None, "foo"), "foo")