Refactor ideal_size template tag to use explicit file existence checks

Author: iampujan

apps/sponsors/templatetags/sponsors.py

@@ -81,14 +81,16 @@ def benefit_name_for_display(benefit, package):
 def ideal_size(image, ideal_dimension):
     """Scale an image width to fit within the given ideal dimension area."""
     ideal_dimension = int(ideal_dimension)
+
+    # image could be an ImageFieldFile; if it's falsey, it means no file is associated with it.
+    if not image:
+        return ideal_dimension
+
     try:
         w, h = image.width, image.height
-    except (FileNotFoundError, ValueError) as e:
+    except FileNotFoundError:
         # local dev doesn't have all images if DB is a copy from prod environment
         # in that case, we return a fallback size to avoid 500 errors.
-        # we only catch the specific ValueError raised by Django when a file is missing.
-        if isinstance(e, ValueError) and "no file associated with it" not in str(e):
-            raise
         return ideal_dimension
 
     return int(w * math.sqrt((100 * ideal_dimension) / (w * h)))

apps/sponsors/tests/test_templatetags.py

@@ -91,43 +91,36 @@ def test_display_name_for_display_from_benefit(self, mocked_name_for_display):
         mocked_name_for_display.assert_called_once_with(package=package)
 
 
-class IdealSizeTemplateTagTests(TestCase):
+    def test_ideal_size_handles_missing_file_association(self):
+        class MockImageWithoutFile:
+            def __bool__(self):
+                return False
+
+        size = ideal_size(MockImageWithoutFile(), 250)
+        # Should return ideal_dimension directly as fallback
+        self.assertEqual(size, 250)
+
     def test_ideal_size_scales_properly(self):
         class MockImage:
             width = 400
             height = 200
 
+            def __bool__(self):
+                return True
+
         size = ideal_size(MockImage(), 200)
         # int(400 * sqrt(20000 / 80000)) = int(400 * 0.5) = 200
         self.assertEqual(size, 200)
 
     def test_ideal_size_handles_file_not_found(self):
-        class MockImageWithoutFile:
+        class MockImageWithMissingFileOnDisk:
             @property
             def width(self):
                 raise FileNotFoundError
 
-        size = ideal_size(MockImageWithoutFile(), 300)
-        # Should return ideal_dimension directly as fallback
-        self.assertEqual(size, 300)
-
-    def test_ideal_size_handles_value_error(self):
-        class MockImageWithoutFileValue:
-            @property
-            def width(self):
-                msg = "The 'web_logo' attribute has no file associated with it."
-                raise ValueError(msg)
+            def __bool__(self):
+                return True
 
-        size = ideal_size(MockImageWithoutFileValue(), 250)
+        size = ideal_size(MockImageWithMissingFileOnDisk(), 300)
         # Should return ideal_dimension directly as fallback
-        self.assertEqual(size, 250)
-
-    def test_ideal_size_raises_other_value_errors(self):
-        class MockImageWithOtherValueError:
-            @property
-            def width(self):
-                msg = "Other error"
-                raise ValueError(msg)
-
-        with self.assertRaises(ValueError):
-            ideal_size(MockImageWithOtherValueError(), 250)
+        self.assertEqual(size, 300)