test: suppress warnings we don't need to see

Author: nedbat

setup.cfg

@@ -0,0 +1,10 @@
+# Licensed under the Apache License: http://www.apache.org/licenses/LICENSE-2.0
+# For details: https://github.com/nedbat/django_coverage_plugin/blob/master/NOTICE.txt
+
+[tool:pytest]
+# How come these warnings are suppressed successfully here, but not in conftest.py??
+filterwarnings =
+    # ignore all DeprecationWarnings...
+    ignore::DeprecationWarning
+    # ...but show them if they are from our code.
+    default::DeprecationWarning:django_coverage_plugin

tests/conftest.py

@@ -0,0 +1,38 @@
+# Licensed under the Apache License: http://www.apache.org/licenses/LICENSE-2.0
+# For details: https://github.com/nedbat/django_coverage_plugin/blob/master/NOTICE.txt
+
+"""
+Pytest auto configuration.
+
+This module is run automatically by pytest, to define and enable fixtures.
+"""
+
+import re
+import warnings
+
+import django.utils.deprecation
+import pytest
+
+
+@pytest.fixture(autouse=True)
+def set_warnings():
+    """Configure warnings to show while running tests."""
+    warnings.simplefilter("default")
+    warnings.simplefilter("once", DeprecationWarning)
+
+    # Warnings to suppress:
+    # How come these warnings are successfully suppressed here, but not in setup.cfg??
+
+    # We know we do tricky things with Django settings, don't warn us about it.
+    warnings.filterwarnings(
+        "ignore",
+        category=UserWarning,
+        message=r"Overriding setting DATABASES can lead to unexpected behavior.",
+        )
+
+    # Django has warnings like RemovedInDjango40Warning.  We use features that are going to be
+    # deprecated, so we don't need to see those warnings. But the specific warning classes change
+    # in every release.  Find them and ignore them.
+    for name, obj in vars(django.utils.deprecation).items():
+        if re.match(r"RemovedInDjango\d+Warning", name):
+            warnings.filterwarnings("ignore", category=obj)