Description of problem:
Package python-pytest-mock fails to build from source in Fedora rawhide.

Version-Release number of selected component (if applicable):
1.10.4-1.fc31

Steps to Reproduce:
koji build --scratch f31 python-pytest-mock-1.10.4-1.fc31.src.rpm

Additional info:
This package is tracked by Koschei. See:
http://apps.fedoraproject.org/koschei/package/python-pytest-mock

This is most likely caused by pytest update from 4.4 to 4.6:

============================= test session starts ==============================
platform linux -- Python 3.7.4, pytest-4.6.4, py-1.8.0, pluggy-0.12.0
rootdir: /builddir/build/BUILD/pytest-mock-1.10.4, inifile: tox.ini
plugins: mock-1.10.4
collected 50 items
test_pytest_mock.py ...............................................F..   [100%]
=================================== FAILURES ===================================
_________________________ test_detailed_introspection __________________________
testdir = <Testdir local('/tmp/pytest-of-mockbuild/pytest-1/test_detailed_introspection0')>
    @pytest.mark.usefixtures("needs_assert_rewrite")
    def test_detailed_introspection(testdir):
        """Check that the "mock_use_standalone" is being used.
        """
        testdir.makepyfile(
            """
            def test(mocker):
                m = mocker.Mock()
                m('fo')
                m.assert_called_once_with('', bar=4)
        """
        )
        result = testdir.runpytest("-s")
        if PY38:
            expected_lines = [
                "*AssertionError: expected call not found.",
                "*Expected: mock('', bar=4)",
                "*Actual: mock('fo')",
            ]
        else:
            expected_lines = [
                "*AssertionError: Expected call: mock('', bar=4)*",
                "*Actual call: mock('fo')*",
            ]
        expected_lines += [
            "*pytest introspection follows:*",
            "*Args:",
            "*assert ('fo',) == ('',)",
            "*At index 0 diff: 'fo' != ''*",
            "*Use -v to get the full diff*",
            "*Kwargs:*",
            "*assert {} == {'bar': 4}*",
            "*Right contains more items:*",
            "*{'bar': 4}*",
            "*Use -v to get the full diff*",
        ]
>       result.stdout.fnmatch_lines(expected_lines)
E       Failed: nomatch: "*AssertionError: Expected call: mock('', bar=4)*"
E           and: '============================= test session starts =============================='
E           and: 'platform linux -- Python 3.7.4, pytest-4.6.4, py-1.8.0, pluggy-0.12.0'
E           and: 'rootdir: /tmp/pytest-of-mockbuild/pytest-1/test_detailed_introspection0'
E           and: 'plugins: mock-1.10.4'
E           and: 'collected 1 item'
E           and: ''
E           and: 'test_detailed_introspection.py F'
E           and: ''
E           and: '=================================== FAILURES ==================================='
E           and: '_____________________________________ test _____________________________________'
E           and: ''
E           and: 'mocker = <pytest_mock.MockFixture object at 0x7fff8d5c8450>'
E           and: ''
E           and: '    def test(mocker):'
E           and: '        m = mocker.Mock()'
E           and: "        m('fo')"
E           and: ">       m.assert_called_once_with('', bar=4)"
E       fnmatch: "*AssertionError: Expected call: mock('', bar=4)*"
E          with: "E       AssertionError: Expected call: mock('', bar=4)"
E       fnmatch: "*Actual call: mock('fo')*"
E          with: "E       Actual call: mock('fo')"
E       nomatch: '*pytest introspection follows:*'
E           and: 'E       '
E       fnmatch: '*pytest introspection follows:*'
E          with: 'E       pytest introspection follows:'
E       nomatch: '*Args:'
E           and: 'E       '
E       fnmatch: '*Args:'
E          with: 'E       Args:'
E       fnmatch: "*assert ('fo',) == ('',)"
E          with: "E       assert ('fo',) == ('',)"
E       fnmatch: "*At index 0 diff: 'fo' != ''*"
E          with: "E         At index 0 diff: 'fo' != ''"
E       fnmatch: '*Use -v to get the full diff*'
E          with: 'E         Use -v to get the full diff'
E       fnmatch: '*Kwargs:*'
E          with: 'E       Kwargs:'
E       fnmatch: "*assert {} == {'bar': 4}*"
E          with: "E       assert {} == {'bar': 4}"
E       nomatch: '*Right contains more items:*'
E           and: 'E         Right contains 1 more item:'
E           and: "E         {'bar': 4}"
E           and: 'E         Use -v to get the full diff'
E           and: ''
E           and: 'test_detailed_introspection.py:4: AssertionError'
E           and: '=========================== 1 failed in 0.08 seconds ==========================='
E           and: ''
E       remains unmatched: '*Right contains more items:*'
/builddir/build/BUILD/pytest-mock-1.10.4/test_pytest_mock.py:646: Failed
----------------------------- Captured stdout call -----------------------------
============================= test session starts ==============================
platform linux -- Python 3.7.4, pytest-4.6.4, py-1.8.0, pluggy-0.12.0
rootdir: /tmp/pytest-of-mockbuild/pytest-1/test_detailed_introspection0
plugins: mock-1.10.4
collected 1 item
test_detailed_introspection.py F
=================================== FAILURES ===================================
_____________________________________ test _____________________________________
mocker = <pytest_mock.MockFixture object at 0x7fff8d5c8450>
    def test(mocker):
        m = mocker.Mock()
        m('fo')
>       m.assert_called_once_with('', bar=4)
E       AssertionError: Expected call: mock('', bar=4)
E       Actual call: mock('fo')
E       
E       pytest introspection follows:
E       
E       Args:
E       assert ('fo',) == ('',)
E         At index 0 diff: 'fo' != ''
E         Use -v to get the full diff
E       Kwargs:
E       assert {} == {'bar': 4}
E         Right contains 1 more item:
E         {'bar': 4}
E         Use -v to get the full diff
test_detailed_introspection.py:4: AssertionError
=========================== 1 failed in 0.08 seconds ===========================
=========================== short test summary info ============================
FAILED test_pytest_mock.py::test_detailed_introspection - Failed: nomatch: "*...
===================== 1 failed, 49 passed in 3.38 seconds ======================