diff --git a/rules-tests/Naming/Naming/PropertyNamingTest.php b/rules-tests/Naming/Naming/PropertyNamingTest.php
index 52ee99d3487..57ae2baeb07 100644
--- a/rules-tests/Naming/Naming/PropertyNamingTest.php
+++ b/rules-tests/Naming/Naming/PropertyNamingTest.php
@@ -26,7 +26,7 @@ public function testGetExpectedNameFromMethodName(string $methodName, ?string $e
         $expectedName = $this->propertyNaming->getExpectedNameFromMethodName($methodName);
 
         if ($expectedPropertyName === null) {
-            $this->assertNull($expectedName);
+            $this->assertNotInstanceOf(ExpectedName::class, $expectedName);
         } else {
             $this->assertInstanceOf(ExpectedName::class, $expectedName);
             $this->assertSame($expectedPropertyName, $expectedName->getSingularized());