TST, MAINT: adjustments for pytest 5.0

[tylerjereddy]

Fixes #10376 ; may require some iteration since I can't reproduce locally.

• prefer importlib over imp to avoid deprecation warnings
  since master branch no longer has a support burden for Python 2

• pytest-faulthandler can be removed from infrastructure and
  docs because it has been merged into pytest core now

[pv]

The deprecated import is in system Python's distutils:

==================================== ERRORS ====================================
________________________ ERROR collecting test session _________________________
/home/travis/virtualenv/python3.6.3/lib/python3.6/site-packages/_pytest/config/__init__.py:415: in _importconftest
    return self._conftestpath2mod[conftestpath]
E   KeyError: local('/home/travis/virtualenv/python3.6.3/lib/python3.6/site-packages/scipy/conftest.py')
During handling of the above exception, another exception occurred:
/home/travis/virtualenv/python3.6.3/lib/python3.6/site-packages/_pytest/config/__init__.py:421: in _importconftest
    mod = conftestpath.pyimport()
/home/travis/virtualenv/python3.6.3/lib/python3.6/site-packages/py/_path/local.py:668: in pyimport
    __import__(modname)
<frozen importlib._bootstrap>:971: in _find_and_load
    ???
<frozen importlib._bootstrap>:955: in _find_and_load_unlocked
    ???
<frozen importlib._bootstrap>:665: in _load_unlocked
    ???
/home/travis/virtualenv/python3.6.3/lib/python3.6/site-packages/_pytest/assertion/rewrite.py:149: in exec_module
    exec(co, module.__dict__)
/home/travis/virtualenv/python3.6.3/lib/python3.6/site-packages/scipy/conftest.py:8: in <module>
    from distutils.version import LooseVersion
/home/travis/virtualenv/python3.6.3/lib/python3.6/distutils/__init__.py:4: in <module>
    import imp
/home/travis/virtualenv/python3.6.3/lib/python3.6/imp.py:33: in <module>
    DeprecationWarning, stacklevel=2)
E   DeprecationWarning: the imp module is deprecated in favour of importlib; see the module's documentation for alternative uses
During handling of the above exception, another exception occurred:
/home/travis/virtualenv/python3.6.3/lib/python3.6/site-packages/_pytest/runner.py:220: in from_call
    result = func()
/home/travis/virtualenv/python3.6.3/lib/python3.6/site-packages/_pytest/runner.py:247: in <lambda>
    call = CallInfo.from_call(lambda: list(collector.collect()), "collect")
/home/travis/virtualenv/python3.6.3/lib/python3.6/site-packages/_pytest/main.py:507: in collect
    yield from self._collect(arg)
/home/travis/virtualenv/python3.6.3/lib/python3.6/site-packages/_pytest/main.py:534: in _collect
    col = self._collectfile(pkginit, handle_dupes=False)
/home/travis/virtualenv/python3.6.3/lib/python3.6/site-packages/_pytest/main.py:597: in _collectfile
    ihook = self.gethookproxy(path)
/home/travis/virtualenv/python3.6.3/lib/python3.6/site-packages/_pytest/main.py:446: in gethookproxy
    my_conftestmodules = pm._getconftestmodules(fspath)
/home/travis/virtualenv/python3.6.3/lib/python3.6/site-packages/_pytest/config/__init__.py:399: in _getconftestmodules
    mod = self._importconftest(conftestpath.realpath())
/home/travis/virtualenv/python3.6.3/lib/python3.6/site-packages/_pytest/config/__init__.py:438: in _importconftest
    raise ConftestImportFailure(conftestpath, sys.exc_info())
E   _pytest.config.ConftestImportFailure: (local('/home/travis/virtualenv/python3.6.3/lib/python3.6/site-packages/scipy/conftest.py'), (<class 'DeprecationWarning'>, DeprecationWarning("the imp module is deprecated in favour of importlib; see the module's documentation for alternative uses",), <traceback object at 0x7ff44a2fa588>))
=========================== short test summary info ============================
FAILED ../.. - _pytest.config.ConftestImportFailure: (local('/home/travis/vir...
!!!!!!!!!!!!!!!!!!! Interrupted: 1 errors during collection !!!!!!!!!!!!!!!!!!!!
=========================== 1 error in 0.29 seconds ============================

We'll just have add it to the ignores.

[pv]

The remaining failure with numpy dev version is #10379

[tylerjereddy]

Pretty sure I'm going to need to backport this to the 1.3.x maintenance branch to resolve similar issues in CI observed there: #10496

[charris]

Might want to upgrade Cython to 0.29.11 for Python 3.8. It's not here yet, but not that far off.

[tylerjereddy]

@charris Do you mean just for the sdist build or also i.e., making additions to pyproject.toml?

@mdhaber Do you know which commit I can backport to resolve the html-scipyorg build failure described in this comment or yours?

[charris]

@tylerjereddy For sdist now, but it should be stable enough that we can start thinking of testing against it, release schedule is here: https://www.python.org/dev/peps/pep-0569/. The python3.8-dev option is available on travis using xenial, which we should already be doing for 3.7. I should probably try this with NumPy also.

[charris]

Put numpy/numpy#14076 up just to see what happens.

[charris]

Looks OK except it is running nose tests which gives the 'imp' deprecation warning. We should maybe disable those tests for recent Python and quiet them for pytest.

[charris]

The timedelta.total_seconds() has an integer conversion problem, I think it is on the python end of things.