test(kyberlib): ✅ Add unit tests for KyberLibError

tests/test_error.rs

@@ -28,4 +28,40 @@ fn test_kyber_lib_error_display() {
         error.to_string(),
         "Random bytes generation function failed"
     );
+
+    let error = KyberLibError::InvalidKey;
+    assert_eq!(
+        error.to_string(),
+        "The secret and public key given does not match."
+    );
+}
+
+#[test]
+fn test_kyber_lib_error_partial_eq() {
+    let error1 = KyberLibError::InvalidInput;
+    let error2 = KyberLibError::InvalidInput;
+    assert_eq!(error1, error2);
+
+    let error1 = KyberLibError::Decapsulation;
+    let error2 = KyberLibError::Decapsulation;
+    assert_eq!(error1, error2);
+
+    let error1 = KyberLibError::RandomBytesGeneration;
+    let error2 = KyberLibError::RandomBytesGeneration;
+    assert_eq!(error1, error2);
+
+    let error1 = KyberLibError::InvalidKey;
+    let error2 = KyberLibError::InvalidKey;
+    assert_eq!(error1, error2);
+
+    let error1 = KyberLibError::InvalidInput;
+    let error2 = KyberLibError::Decapsulation;
+    assert_ne!(error1, error2);
+}
+
+#[cfg(feature = "std")]
+#[test]
+fn test_kyber_lib_error_std_error() {
+    let error = KyberLibError::InvalidInput;
+    let _std_error: &dyn std::error::Error = &error;
 }