Subject: add test for utils

src/utils.rs

@@ -1,3 +1,20 @@
 pub fn is_newline_char(byte: u8) -> bool {
     byte == b'\n'
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_newline_char() {
+        // Test newline character
+        assert_eq!(is_newline_char(b'\n'), true);
+        // Test non-newline characters
+        assert_eq!(is_newline_char(b'a'), false);
+        assert_eq!(is_newline_char(b' '), false);
+        assert_eq!(is_newline_char(b'\t'), false);
+        // Test other newline characters like carriage return
+        assert_eq!(is_newline_char(b'\r'), false);
+    }
+}