diff --git a/tests/Functional/.gitkeep b/tests/Functional/.gitkeep
deleted file mode 100644
index e69de29b..00000000
diff --git a/tests/Functional/Comment/CommentTest.php b/tests/Functional/Comment/CommentTest.php
new file mode 100644
index 00000000..100d2531
--- /dev/null
+++ b/tests/Functional/Comment/CommentTest.php
@@ -0,0 +1,80 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Sabberworm\CSS\Tests\Functional\Comment;
+
+use PHPUnit\Framework\TestCase;
+use Sabberworm\CSS\Comment\Comment;
+use Sabberworm\CSS\OutputFormat;
+
+/**
+ * @covers \Sabberworm\CSS\Comment\Comment
+ */
+final class CommentTest extends TestCase
+{
+    /**
+     * @test
+     */
+    public function toStringRendersCommentEnclosedInCommentDelimiters(): void
+    {
+        $comment = 'There is no spoon.';
+        $subject = new Comment();
+
+        $subject->setComment($comment);
+
+        self::assertSame('/*' . $comment . '*/', (string) $subject);
+    }
+
+    /**
+     * @test
+     */
+    public function renderWithVirginOutputFormatRendersCommentEnclosedInCommentDelimiters(): void
+    {
+        $comment = 'There is no spoon.';
+        $subject = new Comment();
+
+        $subject->setComment($comment);
+
+        self::assertSame('/*' . $comment . '*/', $subject->render(new OutputFormat()));
+    }
+
+    /**
+     * @test
+     */
+    public function renderWithDefaultOutputFormatRendersCommentEnclosedInCommentDelimiters(): void
+    {
+        $comment = 'There is no spoon.';
+        $subject = new Comment();
+
+        $subject->setComment($comment);
+
+        self::assertSame('/*' . $comment . '*/', $subject->render(OutputFormat::create()));
+    }
+
+    /**
+     * @test
+     */
+    public function renderWithCompactOutputFormatRendersCommentEnclosedInCommentDelimiters(): void
+    {
+        $comment = 'There is no spoon.';
+        $subject = new Comment();
+
+        $subject->setComment($comment);
+
+        self::assertSame('/*' . $comment . '*/', $subject->render(OutputFormat::createCompact()));
+    }
+
+    /**
+     * @test
+     */
+    public function renderWithPrettyOutputFormatRendersCommentEnclosedInCommentDelimiters(): void
+    {
+        $comment = 'There is no spoon.';
+        $subject = new Comment();
+
+        $subject->setComment($comment);
+
+        self::assertSame('/*' . $comment . '*/', $subject->render(OutputFormat::createPretty()));
+    }
+}
diff --git a/tests/Unit/Comment/CommentTest.php b/tests/Unit/Comment/CommentTest.php
index c9e07102..2bfe670c 100644
--- a/tests/Unit/Comment/CommentTest.php
+++ b/tests/Unit/Comment/CommentTest.php
@@ -6,7 +6,6 @@
 
 use PHPUnit\Framework\TestCase;
 use Sabberworm\CSS\Comment\Comment;
-use Sabberworm\CSS\OutputFormat;
 use Sabberworm\CSS\Renderable;
 
 /**
@@ -78,30 +77,4 @@ public function getLineNoInitiallyReturnsLineNumberPassedToConstructor(): void
 
         self::assertSame($lineNumber, $subject->getLineNo());
     }
-
-    /**
-     * @test
-     */
-    public function toStringRendersCommentEnclosedInCommentDelimiters(): void
-    {
-        $comment = 'There is no spoon.';
-        $subject = new Comment();
-
-        $subject->setComment($comment);
-
-        self::assertSame('/*' . $comment . '*/', (string) $subject);
-    }
-
-    /**
-     * @test
-     */
-    public function renderRendersCommentEnclosedInCommentDelimiters(): void
-    {
-        $comment = 'There is no spoon.';
-        $subject = new Comment();
-
-        $subject->setComment($comment);
-
-        self::assertSame('/*' . $comment . '*/', $subject->render(new OutputFormat()));
-    }
 }