TST: use pytest name in naming files for check_figures_equal

tacaswell · tacaswell · commit 765e08e643fd · 2020-03-05T22:10:14.000-05:00
If you stacked `pytest.mark.parametrize` with check_figures_equal
every pass through would write to the same files.  This:

 - add a pytest_pyfunc_call implementation hook to monkey-patch the
 test name onto the function
 - has the wrapper function check for the monkey-patched name and use
 that for the base file name
diff --git a/lib/matplotlib/testing/conftest.py b/lib/matplotlib/testing/conftest.py
@@ -29,6 +29,13 @@ def pytest_unconfigure(config):
     matplotlib._called_from_pytest = False
 
 
+@pytest.hookimpl(tryfirst=True, hookwrapper=True)
+def pytest_pyfunc_call(pyfuncitem):
+    item = pyfuncitem
+    item.function._item_name_ = item.name
+    yield
+
+
 @pytest.fixture(autouse=True)
 def mpl_test_settings(request):
     from matplotlib.testing.decorators import _cleanup_cm
diff --git a/lib/matplotlib/testing/decorators.py b/lib/matplotlib/testing/decorators.py
@@ -389,14 +389,14 @@ def decorator(func):
 
         @pytest.mark.parametrize("ext", extensions)
         def wrapper(*args, ext, **kwargs):
+            fn = getattr(wrapper, "_item_name_", func.__name__)
+
             try:
                 fig_test = plt.figure("test")
                 fig_ref = plt.figure("reference")
                 func(*args, fig_test=fig_test, fig_ref=fig_ref, **kwargs)
-                test_image_path = result_dir / (func.__name__ + "." + ext)
-                ref_image_path = result_dir / (
-                    func.__name__ + "-expected." + ext
-                )
+                test_image_path = result_dir / (fn + "." + ext)
+                ref_image_path = result_dir / (fn + "-expected." + ext)
                 fig_test.savefig(test_image_path)
                 fig_ref.savefig(ref_image_path)
                 _raise_on_image_difference(
diff --git a/lib/matplotlib/tests/conftest.py b/lib/matplotlib/tests/conftest.py
@@ -1,4 +1,4 @@
 from matplotlib.testing.conftest import (mpl_test_settings,
                                          mpl_image_comparison_parameters,
                                          pytest_configure, pytest_unconfigure,
-                                         pd)
+                                         pd, pytest_pyfunc_call)
