diff --git a/backend/src/models/test_diff.rs b/backend/src/models/test_diff.rs
deleted file mode 100644
index 3f685968..00000000
--- a/backend/src/models/test_diff.rs
+++ /dev/null
@@ -1,51 +0,0 @@
-#[cfg(test)]
-mod tests {
-    use crate::models::task_attempt::{TaskAttempt, DiffChunkType};
-
-    #[test]
-    fn test_line_based_diff() {
-        let old_content = "line 1\nline 2\nline 3\n";
-        let new_content = "line 1\nmodified line 2\nline 3\n";
-        
-        let chunks = TaskAttempt::generate_line_based_diff(old_content, new_content);
-        
-        // Should have: equal, delete, insert, equal
-        assert_eq!(chunks.len(), 4);
-        
-        // First chunk should be equal
-        assert_eq!(chunks[0].chunk_type, DiffChunkType::Equal);
-        assert_eq!(chunks[0].content, "line 1\n");
-        
-        // Second chunk should be delete
-        assert_eq!(chunks[1].chunk_type, DiffChunkType::Delete);
-        assert_eq!(chunks[1].content, "line 2\n");
-        
-        // Third chunk should be insert
-        assert_eq!(chunks[2].chunk_type, DiffChunkType::Insert);
-        assert_eq!(chunks[2].content, "modified line 2\n");
-        
-        // Fourth chunk should be equal
-        assert_eq!(chunks[3].chunk_type, DiffChunkType::Equal);
-        assert_eq!(chunks[3].content, "line 3\n");
-    }
-    
-    #[test]
-    fn test_line_insertion() {
-        let old_content = "line 1\nline 3\n";
-        let new_content = "line 1\nline 2\nline 3\n";
-        
-        let chunks = TaskAttempt::generate_line_based_diff(old_content, new_content);
-        
-        // Should have: equal, insert, equal
-        assert_eq!(chunks.len(), 3);
-        
-        assert_eq!(chunks[0].chunk_type, DiffChunkType::Equal);
-        assert_eq!(chunks[0].content, "line 1\n");
-        
-        assert_eq!(chunks[1].chunk_type, DiffChunkType::Insert);
-        assert_eq!(chunks[1].content, "line 2\n");
-        
-        assert_eq!(chunks[2].chunk_type, DiffChunkType::Equal);
-        assert_eq!(chunks[2].content, "line 3\n");
-    }
-}