Move most of pytest's conf to conftest.py.

anntzer · anntzer · commit 2cd914d5894f · 2019-07-01T07:41:38.000+02:00
pytest.ini is not found if running the test suite from anywhere but
a source checkout root.  For example, it is not found if running
`matplotlib.test()` from an installed Matplotlib (that includes test
data). mplcairo's test suite also relies on being able to run the
Matplotlib test suite from not-the-source-tree (via `pytest --pyargs
matplotlib`).

This is particularly problematic now that pytest requires markers to be
explicitly declared, and emits a warning when they are not.

Instead, declare most relevant options in pytest_configure().  (Note
that this actually only helps mplcairo when used in conjunction of
pytest&gt;=5.0 due to pytest issue 5078, but the patch doesn't bump the
pytest version requirement for matplotlib.)

See also pytest issue 4039.
diff --git a/lib/matplotlib/testing/conftest.py b/lib/matplotlib/testing/conftest.py
@@ -5,6 +5,21 @@
 
 
 def pytest_configure(config):
+    # config is initialized here rather than in pytest.ini so that `pytest
+    # --pyargs matplotlib` (which would not find pytest.ini) works.  The only
+    # entries in pytest.ini set minversion (which is checked earlier) and
+    # testpaths/python_files, as they are required to properly find the tests.
+    for key, value in [
+        ("markers", "flaky: (Provided by pytest-rerunfailures.)"),
+        ("markers", "timeout: (Provided by pytest-timeout.)"),
+        ("markers", "backend: Set alternate Matplotlib backend temporarily."),
+        ("markers", "style: Set alternate Matplotlib style temporarily."),
+        ("markers", "baseline_images: Compare output against references."),
+        ("markers", "pytz: Tests that require pytz to be installed."),
+        ("filterwarnings", "error"),
+    ]:
+        config.addinivalue_line(key, value)
+
     matplotlib.use('agg', force=True)
     matplotlib._called_from_pytest = True
     matplotlib._init_tests()
diff --git a/pytest.ini b/pytest.ini
@@ -1,16 +1,6 @@
+# Additional configuration is in matplotlib/testing/conftest.py.
 [pytest]
 minversion = 3.6
 
 testpaths = lib
 python_files = test_*.py
-
-markers =
-    flaky: (Provided by pytest-rerunfailures.)
-    timeout: (Provided by pytest-timeout.)
-    backend: Set alternate Matplotlib backend temporarily.
-    style: Set alternate Matplotlib style temporarily.
-    baseline_images: Compare output against a known reference.
-    pytz: Tests that require pytz to be installed.
-
-filterwarnings =
-    error
