some of our tests now fail due to pytest=5.4.0

[DougBurke]

Some of Omar's data-regridding tests are now failing because they rely on an "accidental" feature which has now been "fixed". See pytest-dev/pytest#6909 for more details (and it's not just us that has been bitten by this).

For reference, the tests fail with a message like

==================================== test session starts =====================================
platform linux -- Python 3.8.1, pytest-5.4.0, py-1.8.1, pluggy-0.13.1
rootdir: /home/dburke
collected 2329 items / 1 error / 2328 selected

=========================================== ERRORS ===========================================
_ ERROR collecting anaconda/envs/sherpa-wtf/lib/python3.8/site-packages/sherpa-4.12.0+121.g2d36b10e.dirty-py3.8-linux-x86_64.egg/sherpa/models/tests/test_regrid_unit.py _
In function "test_evaluation_space2d_overlaps":
Parameter "x_overlaps" should be declared explicitly via indirect or in function itself
!!!!!!!!!!!!!!!!!!!!!!!!!!! Interrupted: 1 error during collection !!!!!!!!!!!!!!!!!!!!!!!!!!!
====================================== 1 error in 1.23s ======================================

It also does not hit all our test configurations on Travis; I don't know if that's just that the new version hasn't made it to all set ups yet or something more interesting on how we set things up.

[DougBurke]

Explicitly setting the indirect argument, as shown below, makes the tests run, but they now fail

@pytest.mark.parametrize('x_overlaps, y_overlaps', [
    (True, True),
    (True, False),
    (False, False),
], indirect=True)
@pytest.mark.parametrize('integrated', [
    True, False
], indirect=True)
def test_evaluation_space2d_overlaps(setup_overlapping_spaces):

which creates

=========================================== ERRORS ===========================================
_____________ ERROR at setup of test_evaluation_space2d_overlaps[True-True-True] _____________
file /home/dburke/anaconda/envs/sherpa-wtf/lib/python3.8/site-packages/sherpa-4.12.0+121.g2d36b10e.dirty-py3.8-linux-x86_64.egg/sherpa/models/tests/test_regrid_unit.py, line 852
  @pytest.mark.parametrize('x_overlaps, y_overlaps', [
      (True, True),
      (True, False),
      (False, False),
  ], indirect=True)
  @pytest.mark.parametrize('integrated', [
      True, False
  ], indirect=True)
  def test_evaluation_space2d_overlaps(setup_overlapping_spaces):
file /home/dburke/anaconda/envs/sherpa-wtf/lib/python3.8/site-packages/sherpa-4.12.0+121.g2d36b10e.dirty-py3.8-linux-x86_64.egg/sherpa/models/tests/test_regrid_unit.py, line 884
  @pytest.fixture
  def setup_overlapping_spaces(integrated, x_overlaps, y_overlaps):
E       fixture 'integrated' not found
>       available fixtures: cache, capfd, capfdbinary, caplog, capsys, capsysbinary, capture_all_warnings, clean_astro_ui, clean_ui, doctest_namespace, make_data_path, monkeypatch, pytestconfig, record_property, record_testsuite_property, record_xml_attribute, recwarn, restore_xspec_settings, run_thread, setup_1d, setup_overlapping_spaces, test_data_path, tmp_path, tmp_path_factory, tmpdir, tmpdir_factory
>       use 'pytest --fixtures [testpath]' for help on them.

/home/dburke/anaconda/envs/sherpa-wtf/lib/python3.8/site-packages/sherpa-4.12.0+121.g2d36b10e.dirty-py3.8-linux-x86_64.egg/sherpa/models/tests/test_regrid_unit.py:884
____________ ERROR at setup of test_evaluation_space2d_overlaps[True-True-False] _____________
...

Oooh. It looks like we just need to add x_overlaps, y_overlaps, integrated to the argument list to test_evaluation_space2d_overlaps and everything will be golden. Expect a PR.