diff --git a/tests/Rules/AbstractRuleTestCase.php b/tests/Rules/AbstractRuleTestCase.php
index 2c99c332..23d600db 100644
--- a/tests/Rules/AbstractRuleTestCase.php
+++ b/tests/Rules/AbstractRuleTestCase.php
@@ -75,7 +75,12 @@ protected function checkRule(
 
             $id = $violation->getIdentifier()?->toString() ?? '';
             if (isset($messages[$id])) {
-                static::fail(sprintf('Two violations have the same identifier "%s".', $id));
+                static::fail(sprintf(
+                    'Two violations have the same identifier "%s": the messages are "%s" and "%s".',
+                    $id,
+                    $messages[$id],
+                    $message,
+                ));
             }
 
             $messages[$id] = $message;