[tests/test_mc] Fix Montgomery tests in the CI

tests/test_mc.py

@@ -106,13 +106,7 @@ def test_loading():
 
     image_size_portrait = (4020, 4892)
     image_size_landscape = (4892, 4020)
-
-    def _check_size(size):
-        if size == image_size_portrait:
-            return True
-        elif size == image_size_landscape:
-            return True
-        return False
+    image_size_test = (512, 512)
 
     def _check_sample(s):
         data = s.data
@@ -120,7 +114,11 @@ def test_loading():
         assert len(data) == 2
 
         assert "data" in data
-        assert _check_size(data["data"].size)  # Check size
+        assert data["data"].size in (
+            image_size_portrait,
+            image_size_landscape,
+            image_size_test,
+        )
         assert data["data"].mode == "L"  # Check colors
 
         assert "label" in data