diff --git a/tests/Unit/CSSList/DocumentTest.php b/tests/Unit/CSSList/DocumentTest.php
index 7b6a3df9c..baec691b7 100644
--- a/tests/Unit/CSSList/DocumentTest.php
+++ b/tests/Unit/CSSList/DocumentTest.php
@@ -237,4 +237,14 @@ public function getAllDeclarationBlocksIgnoresCharset(): void
 
         self::assertSame([], $result);
     }
+
+    /**
+     * @test
+     */
+    public function isRootListAlwaysReturnsTrue(): void
+    {
+        $subject = new Document();
+
+        self::assertTrue($subject->isRootList());
+    }
 }