test(math_test_utils): add unit tests for is_quad_residue_mod_prime

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: naor-starkware

vm/src/tests/cairo_test_suite/test_math/math_test_utils.rs

@@ -18,3 +18,21 @@ pub fn is_quad_residue_mod_prime(a: &BigUint) -> i64 {
         Err(_) => -1,
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    /// Returns 1 for a known quadratic residue: 4 = 2² mod CAIRO_PRIME.
+    #[test]
+    fn is_quad_residue_mod_prime_returns_1_for_residue() {
+        assert_eq!(is_quad_residue_mod_prime(&BigUint::from(4u32)), 1);
+    }
+
+    /// Returns 0 for a known non-residue: 3 is not a square mod CAIRO_PRIME.
+    #[test]
+    fn is_quad_residue_mod_prime_returns_0_for_non_residue() {
+        assert_eq!(is_quad_residue_mod_prime(&BigUint::from(3u32)), 0);
+    }
+
+}