ENH: add pytest flag + restore default values via ENV

tacaswell · tacaswell · commit cab2a30bef27 · 2023-06-20T21:12:47.000-04:00
diff --git a/lib/matplotlib/testing/decorators.py b/lib/matplotlib/testing/decorators.py
@@ -122,11 +122,12 @@ class _ImageComparisonBase:
     This class provides *just* the comparison-related functionality and avoids
     any code that would be specific to any testing framework.
     """
-    def __init__(self, func, tol, remove_text, savefig_kwargs):
+    def __init__(self, func, tol, remove_text, savefig_kwargs, external_images):
         self.func = func
         self.result_dir = _results_directory(func)
+        print(external_images)
         (self.root_dir, mod_dir, image_list, self.md_path) = _baseline_directory(
-             func, os.environ.get("MPLTESTIMAGEPATH", None)
+             func, external_images
          )
         self.image_revs = _load_blame(image_list)
         self.baseline_dir = self.root_dir / mod_dir
@@ -293,8 +294,11 @@ def wrapper(*args, extension, request, **kwargs):
                 }.get(extension, 'on this system')
                 pytest.skip(f"Cannot compare {extension} files {reason}")
 
-            img = _ImageComparisonBase(func, tol=tol, remove_text=remove_text,
-                                       savefig_kwargs=savefig_kwargs)
+            img = _ImageComparisonBase(
+                func,
+                tol=tol, remove_text=remove_text, savefig_kwargs=savefig_kwargs,
+                external_images=request.config.getoption("--image-baseline")
+            )
             matplotlib.testing.set_font_settings_for_testing()
 
             with _collect_new_figures() as figs:
diff --git a/lib/matplotlib/testing/generate_images_plugin.py b/lib/matplotlib/testing/generate_images_plugin.py
@@ -1,13 +1,20 @@
 import pytest
+import os
 
 
 def pytest_addoption(parser):
     parser.addoption(
             "--generate-images",
              action="store_true",
-             default=False,
+             default=bool(os.environ.get('MPLGENERATEBASELINE', False)),
              help="run matplotlib baseline image generation tests"
     )
+    parser.addoption(
+            "--image-baseline",
+             default=os.environ.get('MPLBASELINEIMAGES', None),
+             help="run matplotlib baseline image generation tests",
+        type=str
+    )
 
 
 def pytest_collection_modifyitems(config, items):
