diff --git a/pkg/service/v1/config-service_test.go b/pkg/service/v1/config-service_test.go
index b9a71d50b0b756b5bbd14ae87a931c751f33d626..aac0a6fa798981303e1ad424680fe152ef667e2a 100644
--- a/pkg/service/v1/config-service_test.go
+++ b/pkg/service/v1/config-service_test.go
@@ -60,5 +60,8 @@ func TestReadinessServiceServer_CheckIfReady(t *testing.T) {
 func TestCertManagerServiceServer_DeleteIfExists(t *testing.T) {
 	server := NewCertManagerServiceServer(testclient.NewSimpleClientset())
 
-	res, err := server.DeleteIfExists(context.Background(), &req)
+	res, err := server.DeleteIfExists(context.Background(), &illegal_req)
+	if err == nil || res != nil {
+		t.Fail()
+	}
 }
\ No newline at end of file