fix: update matches_requested_range to handle clamped ranges

After clamping range ends and suffixes to file size, the response
range can be shorter than what was originally requested. Relax the
equality checks to accept clamped responses:

- `Range`: accept response end <= requested end
- `Suffix`: accept response length <= requested suffix

Add tests for suffix edge cases: response not ending at file
boundary, and response length exceeding the requested suffix.

Author: mi-caren

src/headers/content_range.rs

@@ -30,9 +30,10 @@ impl HttpContentRange {
             (
                 HttpRange::Range(OrderedRange { start, end }),
                 HttpContentRange::Bound(Bound { range, .. }),
-            ) => start == range.start() && end == range.end(),
+            ) => start == range.start() && end >= range.end(),
             (HttpRange::Suffix(suffix), HttpContentRange::Bound(Bound { range, size })) => {
-                let length_matches = (range.end() - range.start()).checked_add(1) == Some(suffix);
+                let length = (range.end() - range.start()).checked_add(1);
+                let length_matches = length.is_some_and(|len| len <= suffix);
                 let ends_at_boundary = size.is_none_or(|size| range.end() + 1 == size);
                 length_matches && ends_at_boundary
             }

src/headers/tests.rs

@@ -160,6 +160,38 @@ mod content_range {
 
             assert!(!content_range.matches_requested_range(range));
         }
+
+        #[test]
+        fn range_with_clamped_end_matches() {
+            let range = HttpRange::Range(OrderedRange::new(0..=999).unwrap());
+            let content_range = HttpContentRange::Bound(Bound::new(0..=49, Some(50)).unwrap());
+
+            assert!(content_range.matches_requested_range(range));
+        }
+
+        #[test]
+        fn suffix_clamped_to_file_size_matches() {
+            let range = HttpRange::Suffix(999);
+            let content_range = HttpContentRange::Bound(Bound::new(0..=49, Some(50)).unwrap());
+
+            assert!(content_range.matches_requested_range(range));
+        }
+
+        #[test]
+        fn suffix_not_at_boundary_does_not_match() {
+            let range = HttpRange::Suffix(5);
+            let content_range = HttpContentRange::Bound(Bound::new(0..=4, Some(20)).unwrap());
+
+            assert!(!content_range.matches_requested_range(range));
+        }
+
+        #[test]
+        fn suffix_length_mismatch_does_not_match() {
+            let range = HttpRange::Suffix(3);
+            let content_range = HttpContentRange::Bound(Bound::new(10..=19, Some(20)).unwrap());
+
+            assert!(!content_range.matches_requested_range(range));
+        }
     }
 }