Use pytest-warnings in test script

  $PIP install -r $REQUIREMENTS_TXT

fi

$PIP install pytest

$PIP install pytest pytest-warnings

${PY_EXE} setup.py install

    ulimit -c unlimited

    # Need to set both _TEST and _CTX because doctests do not use _TEST.

    ${PY_EXE} -m pytest -rw --tb=native  -rxs $TESTABLES

    ${PY_EXE} -m pytest -rw --tb=native  -rxsw $TESTABLES

    # Avoid https://github.com/pytest-dev/pytest/issues/754:

    # add --tb=native