test: preserve image baselines across Matplotlib text renderers

tests/data/test_threadcontainer.py

@@ -11,18 +11,16 @@
 
 from __future__ import annotations
 
-import os
 import tempfile
 import time
 import unittest
-from pathlib import Path
 
 import torch
 
 from monai.data import DataLoader
 from monai.utils import optional_import, set_determinism
 from monai.utils.enums import CommonKeys
-from tests.test_utils import SkipIfNoModule
+from tests.test_utils import SkipIfNoModule, get_matplotlib_baseline
 
 try:
     _, has_ignite = optional_import("ignite")
@@ -70,9 +68,6 @@ def test_container(self):
     @SkipIfNoModule("matplotlib")
     def test_plot(self):
         set_determinism(0)
-        test_dir = Path(__file__).parents[1]
-        testing_dir = os.path.join(test_dir, "testing_data")
-
         net = torch.nn.Conv2d(1, 1, 3, padding=1)
 
         opt = torch.optim.Adam(net.parameters())
@@ -105,7 +100,7 @@ def test_plot(self):
         with tempfile.TemporaryDirectory() as tempdir:
             tempimg = f"{tempdir}/threadcontainer_plot_test.png"
             fig.savefig(tempimg)
-            comp = compare_images(f"{testing_dir}/threadcontainer_plot_test.png", tempimg, 5e-2)
+            comp = compare_images(get_matplotlib_baseline("threadcontainer_plot_test.png"), tempimg, 5e-2)
 
             self.assertIsNone(comp, comp)  # None indicates test passed
 

tests/test_matplotlib_baseline.py

@@ -0,0 +1,50 @@
+# Copyright (c) MONAI Consortium
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#     http://www.apache.org/licenses/LICENSE-2.0
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from __future__ import annotations
+
+import unittest
+from unittest.mock import patch
+
+from tests.test_utils import MODULE_PATH, SkipIfNoModule, get_matplotlib_baseline
+
+
+@SkipIfNoModule("matplotlib")
+class TestMatplotlibBaseline(unittest.TestCase):
+    def test_renderer_boundary(self):
+        cases = (
+            ("3.9.4", False),
+            ("3.10.9", False),
+            ("3.10.99", False),
+            ("3.11.0.dev0", True),
+            ("3.11.0a1", True),
+            ("3.11.0rc1", True),
+            ("3.11.0", True),
+            ("3.11.2", True),
+            ("3.12.0.dev0", True),
+            ("4.0.0", True),
+        )
+        for version, modern in cases:
+            with self.subTest(version=version), patch("matplotlib.__version__", version):
+                expected = MODULE_PATH / "tests" / "testing_data"
+                if modern:
+                    expected /= "matplotlib_3_11"
+                self.assertEqual(get_matplotlib_baseline("matshow3d_test.png"), expected / "matshow3d_test.png")
+
+    def test_missing_reference_does_not_fall_back(self):
+        with patch("matplotlib.__version__", "3.11.2"):
+            path = get_matplotlib_baseline("missing-reference.png")
+        self.assertEqual(path.parent.name, "matplotlib_3_11")
+        self.assertFalse(path.exists())
+
+
+if __name__ == "__main__":
+    unittest.main()

tests/test_utils.py

@@ -50,7 +50,7 @@
 from monai.data import create_test_image_2d, create_test_image_3d
 from monai.data.meta_tensor import MetaTensor, get_track_meta
 from monai.networks import convert_to_onnx, convert_to_torchscript
-from monai.utils import optional_import
+from monai.utils import optional_import, version_geq
 from monai.utils.misc import MONAIEnvVars
 from monai.utils.module import compute_capabilities_after, pytorch_after
 from monai.utils.tf32 import detect_default_tf32
@@ -101,6 +101,15 @@ def testing_data_config(*keys):
     return reduce(operator.getitem, keys, _test_data_config)
 
 
+def get_matplotlib_baseline(filename: str) -> Path:
+    """Select the reference for the pre-3.11 or 3.11+ text renderer."""
+    matplotlib_version, _ = optional_import("matplotlib", name="__version__")
+    directory = MODULE_PATH / "tests" / "testing_data"
+    if version_geq(matplotlib_version, "3.11.0.dev0"):
+        directory /= "matplotlib_3_11"
+    return directory / filename
+
+
 def get_testing_algo_template_path():
     """
     a local folder to the testing algorithm template or a url to the compressed template file.

tests/visualize/utils/test_matshow3d.py

@@ -28,7 +28,7 @@
 )
 from monai.utils import optional_import
 from monai.visualize.utils import matshow3d
-from tests.test_utils import SkipIfNoModule
+from tests.test_utils import SkipIfNoModule, get_matplotlib_baseline
 
 compare_images, _ = optional_import("matplotlib.testing.compare", name="compare_images")
 pyplot, has_pyplot = optional_import("matplotlib", name="pyplot")
@@ -57,7 +57,7 @@ def test_3d(self):
         with tempfile.TemporaryDirectory() as tempdir:
             tempimg = f"{tempdir}/matshow3d_test.png"
             fig.savefig(tempimg)
-            comp = compare_images(f"{testing_dir}/matshow3d_test.png", tempimg, 5e-2)
+            comp = compare_images(get_matplotlib_baseline("matshow3d_test.png"), tempimg, 5e-2)
             self.assertIsNone(comp, f"value of comp={comp}")  # None indicates test passed
 
         _, axes = pyplot.subplots()
@@ -86,8 +86,9 @@ def test_samples(self):
         with tempfile.TemporaryDirectory() as tempdir:
             tempimg = f"{tempdir}/matshow3d_patch_test.png"
             fig.savefig(tempimg)
-            comp = compare_images(f"{testing_dir}/matshow3d_patch_test.png", tempimg, 5e-2, in_decorator=True)
-            if comp:
+            baseline = get_matplotlib_baseline("matshow3d_patch_test.png")
+            comp = compare_images(baseline, tempimg, 5e-2, in_decorator=True)
+            if comp and baseline == Path(testing_dir) / "matshow3d_patch_test.png":
                 print("not none comp: ", comp)  # matplotlib 3.2.2
                 np.testing.assert_allclose(comp["rms"], 30.786983, atol=1e-3, rtol=1e-3)
             else:
@@ -125,7 +126,7 @@ def test_3d_rgb(self):
         with tempfile.TemporaryDirectory() as tempdir:
             tempimg = f"{tempdir}/matshow3d_rgb_test.png"
             fig.savefig(tempimg)
-            comp = compare_images(f"{testing_dir}/matshow3d_rgb_test.png", tempimg, 5e-2)
+            comp = compare_images(get_matplotlib_baseline("matshow3d_rgb_test.png"), tempimg, 5e-2)
             self.assertIsNone(comp, f"value of comp={comp}")  # None indicates test passed