TST/MNT: deprecate unused fixture

This is left over from an early pass at nose -> pytest conversion

Author: tacaswell

doc/api/next_api_changes/deprecations/20795-TAC.rst

@@ -0,0 +1,5 @@
+Remove unused pytest fixture
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+The fixture ``matplotlib.testing.conftest.mpl_image_comparison_parameters``
+is not used internally by Matplotlib.  If you use this please copy it
+into your code base.

lib/matplotlib/testing/conftest.py

@@ -97,6 +97,7 @@ def mpl_test_settings(request):
 
 
 @pytest.fixture
+@_api.deprecated("3.5", alternative="none")
 def mpl_image_comparison_parameters(request, extension):
     # This fixture is applied automatically by the image_comparison decorator.
     #

lib/matplotlib/tests/conftest.py

@@ -1,4 +1,3 @@
 from matplotlib.testing.conftest import (mpl_test_settings,
-                                         mpl_image_comparison_parameters,
                                          pytest_configure, pytest_unconfigure,
                                          pd)

lib/mpl_toolkits/tests/conftest.py

@@ -1,3 +1,2 @@
 from matplotlib.testing.conftest import (mpl_test_settings,
-                                         mpl_image_comparison_parameters,
                                          pytest_configure, pytest_unconfigure)