Python: self.assertEqual(a, b, msg) --> I want diff AND msg -

if call this, see nice diff:

self.assertequal(a, b) 

if call this, see msg only:

self.assertequal(a, b, msg) 

is there easy way show diff , msg?

implementing assertequal() myself work, ask myself if best way.

plattform: python2.7 , pytest 2.6.2.

if set longmessage attribute true, see both message.

example:

class testfoo(unittest.testcase):      longmessage = true  # <--      def test_foo(self):         self.assertequal(1+2, 2, 'custom message') 

output:

f ====================================================================== fail: test_foo (__main__.testfoo) ---------------------------------------------------------------------- traceback (most recent call last):   file "t.py", line 6, in test_foo     self.assertequal(1+2, 2, 'custom message') assertionerror: 3 != 2 : custom message  ---------------------------------------------------------------------- ran 1 test in 0.000s