[tests/test_mc] Simplify Montgomery loading tests

tests/test_mc.py

@@ -104,10 +104,6 @@ def test_protocol_consistency():
 def test_loading():
     from ptbench.data.montgomery import dataset
 
-    image_size_portrait = (4020, 4892)
-    image_size_landscape = (4892, 4020)
-    image_size_test = (512, 512)
-
     def _check_sample(s):
         data = s.data
         assert isinstance(data, dict)
@@ -115,9 +111,9 @@ def test_loading():
 
         assert "data" in data
         assert data["data"].size in (
-            image_size_portrait,
-            image_size_landscape,
-            image_size_test,
+            (4020, 4892),  # portrait
+            (4892, 4020),  # landscape
+            (512, 512),  # test database @ CI
         )
         assert data["data"].mode == "L"  # Check colors