fix: report file size limits correctly in image validation errors

care/utils/models/validators.py

@@ -250,13 +250,20 @@ def __eq__(self, other: object) -> bool:
             ]
         )
 
-    def _humanize_bytes(self, size: int) -> str:
+    @staticmethod
+    def _format_size(size: float) -> str:
+        # Trim the trailing zeros of the fixed-point form first, then the bare
+        # decimal point. Stripping "." and "0" in one pass also eats the
+        # significant zeros of a round number, turning 10.00 into "1".
+        return f"{size:.2f}".rstrip("0").rstrip(".")
+
+    def _humanize_bytes(self, size: float) -> str:
         byte_size = 1024.0
         for unit in ["B", "KB"]:
             if size < byte_size:
-                return f"{f'{size:.2f}'.rstrip('.0')} {unit}"
+                return f"{self._format_size(size)} {unit}"
             size /= byte_size
-        return f"{f'{size:.2f}'.rstrip('.0')} MB"
+        return f"{self._format_size(size)} MB"
 
 
 cover_image_validator = ImageSizeValidator(

care/utils/tests/test_image_validator.py

@@ -60,3 +60,37 @@ def test_invalid_image_too_large(self):
                 "Image size is greater than the maximum allowed size of 2 MB.",
             ],
         )
+
+    def _image_file(self, reported_size: int) -> UploadedFile:
+        image = Image.new("RGB", (10, 10))
+        file = io.BytesIO()
+        image.save(file, format="JPEG")
+        return UploadedFile(file, "test.jpg", "image/jpeg", reported_size)
+
+    def test_min_size_limit_is_reported_verbatim(self):
+        for min_size, expected in [
+            (500, "500 B"),
+            (1536, "1.5 KB"),
+            (10 * 1024, "10 KB"),
+            (10 * 1024 * 1024, "10 MB"),
+        ]:
+            with self.subTest(min_size=min_size):
+                validator = ImageSizeValidator(min_size=min_size)
+                with self.assertRaises(ValidationError) as cm:
+                    validator(self._image_file(1))
+                self.assertEqual(
+                    cm.exception.messages,
+                    [
+                        "Image size is less than the minimum allowed size of "
+                        f"{expected}.",
+                    ],
+                )
+
+    def test_max_size_limit_is_reported_verbatim(self):
+        validator = ImageSizeValidator(max_size=10 * 1024 * 1024)
+        with self.assertRaises(ValidationError) as cm:
+            validator(self._image_file(20 * 1024 * 1024))
+        self.assertEqual(
+            cm.exception.messages,
+            ["Image size is greater than the maximum allowed size of 10 MB."],
+        )