diff --git a/halo2_frontend/src/circuit/value.rs b/halo2_frontend/src/circuit/value.rs
index e0426f6bfa..0eae892e83 100644
--- a/halo2_frontend/src/circuit/value.rs
+++ b/halo2_frontend/src/circuit/value.rs
@@ -697,3 +697,15 @@ impl<F: Field> Value<Assigned<F>> {
         }
     }
 }
+
+#[cfg(test)]
+mod test {
+    use super::*;
+    type V = Value<u64>;
+
+    #[test]
+    fn test_check_inits() {
+        assert_eq!(V::unknown().inner, None);
+        assert_eq!(V::default(),V::unknown());
+    }
+}