diff --git a/tests/Unit/RuleSet/RuleSetTest.php b/tests/Unit/RuleSet/RuleSetTest.php
index 27e8aaee7..92c056ca0 100644
--- a/tests/Unit/RuleSet/RuleSetTest.php
+++ b/tests/Unit/RuleSet/RuleSetTest.php
@@ -53,11 +53,12 @@ public function getLineNumberByDefaultReturnsNull(): void
     }
 
     /**
-     * @return array<non-empty-string, array{0: int<1, max>}>
+     * @return array<non-empty-string, array{0: int<1, max>|null}>
      */
     public function provideLineNumber(): array
     {
         return [
+            'null' => [null],
             'line 1' => [1],
             'line 42' => [42],
         ];
@@ -66,11 +67,11 @@ public function provideLineNumber(): array
     /**
      * @test
      *
-     * @param int<1, max> $lineNumber
+     * @param int<1, max>|null $lineNumber
      *
      * @dataProvider provideLineNumber
      */
-    public function getLineNumberReturnsLineNumberPassedToConstructor(int $lineNumber): void
+    public function getLineNumberReturnsLineNumberPassedToConstructor(?int $lineNumber): void
     {
         $subject = new RuleSet($lineNumber);