pylint complains assertRaisesRegex is deprecated

[smoser]

Steps to reproduce

We have unit tests that we need to work in python 2.6 all the way to 3.6.

Older unittest2.TestCase (as seen in CentOS 6) do not have an
assertRaisesRegex method. They only have the now-deprecated
assertRaisesRegexp.

We need our unit tests to work there and on newer python (3.6),
so we just fill the method in as seen in the test case.

This causes pylint to complain that assertRaisesRegex is deprecated.

One thing to note is that we can work around this by using getattr:

  if not hasattr(TestCase, 'assertRaisesRegex'):
      TestCase.assertRaisesRegex = getattr(TestCase, 'assertRaisesRegexp')

1. Create mytest.py

    $ cat mytest.py
    from unittest2 import TestCase
   
    if not hasattr(TestCase, 'assertRaisesRegex'):
        TestCase.assertRaisesRegex = TestCase.assertRaisesRegexp
   
    class TestMe(TestCase):
        """Test Regex"""
   
        def test_my_regex(self):
            """Use assertRaisesRegex."""
            value = "9a"
            with self.assertRaisesRegex(ValueError, r"invalid.*%s" % value):
                int(value)
   

2. Run pylint on file

Current behavior

  $ python3 -m pylint --rcfile=/dev/null mytest.py
  Using config file /dev/null
  ************* Module mytest
  W: 25,13: Using deprecated method assertRaisesRegex() (deprecated-method)

Note that it actually complains on the use of assertRaisesRegex (not assertRaisesRegexp)
and the warning comes not from the hackery but the use of assertRaisesRegex.

Expected behavior

No errors on assertRaisesRegex are expected.

pylint --version output

  $ python3 -m pylint --rcfile=/dev/null --version
  Using config file /dev/null
  __main__.py 1.8.2, 
  astroid 1.6.1
  Python 3.6.4+ (default, Feb 12 2018, 08:25:03) 
  [GCC 7.3.0]

[brycepg]

For some reason the inference of the attribute assertRaisesRegex is inferring to [<BoundMethod assertRaisesRegex of unittest2.case.TestCase at 0x131180310620816, <BoundMethod deprecated_func of unittest2.case.TestCase._deprecate at 0x131180310652744, <BoundMethod deprecated_func of unittest.case.TestCase._deprecate at 0x131180310653584, <BoundMethod assertRaisesRegex of unittest.case.TestCase at 0x131180310651064]
Which contains the a "deprecate" decorator that pylint makes note of. Some debugging needs to be done in astroid as to why the inference system is doing this.

[wulfgarpro]

+1

[PCManticore]

This should be fixed in the master branch now.