diff --git a/src/test/java/net/kemitix/mon/ResultTest.java b/src/test/java/net/kemitix/mon/ResultTest.java
index 1386251..2a2f35e 100644
--- a/src/test/java/net/kemitix/mon/ResultTest.java
+++ b/src/test/java/net/kemitix/mon/ResultTest.java
@@ -15,6 +15,7 @@ public class ResultTest implements WithAssertions {
         final RuntimeException runtimeException = new RuntimeException();
         assertThat(Result.ok(1)).isNotEqualTo(Result.error(runtimeException));
         assertThat(Result.error(runtimeException)).isEqualTo(Result.error(runtimeException));
+        assertThat(Result.error(runtimeException)).isNotEqualTo(Result.error(new RuntimeException()));
         assertThat(Result.ok(1).equals("1")).isFalse();
         assertThat(Result.error(new RuntimeException()).equals("1")).isFalse();
     }