[CLEANUP] Add some comments for grouping tests (#978)

Part of #973

Author: oliverklee

tests/Unit/CSSList/AtRuleBlockListTest.php

@@ -16,6 +16,10 @@
  */
 final class AtRuleBlockListTest extends TestCase
 {
+    /*
+    * Tests for the implemented interfaces
+    */
+
     /**
      * @test
      */
@@ -46,6 +50,10 @@ public function implementsCommentable(): void
         self::assertInstanceOf(Commentable::class, $subject);
     }
 
+    /*
+     * not grouped yet
+     */
+
     /**
      * @test
      */

tests/Unit/CSSList/DocumentTest.php

@@ -22,6 +22,10 @@
  */
 final class DocumentTest extends TestCase
 {
+    /*
+    * Tests for the implemented interfaces
+    */
+
     /**
      * @test
      */
@@ -38,6 +42,10 @@ public function implementsCommentable(): void
         self::assertInstanceOf(Commentable::class, new Document());
     }
 
+    /*
+     * not grouped yet
+     */
+
     /**
      * @test
      */

tests/Unit/CSSList/KeyFrameTest.php

@@ -16,6 +16,10 @@
  */
 final class KeyFrameTest extends TestCase
 {
+    /*
+    * Tests for the implemented interfaces
+    */
+
     /**
      * @test
      */
@@ -46,6 +50,10 @@ public function implementsCommentable(): void
         self::assertInstanceOf(Commentable::class, $subject);
     }
 
+    /*
+     * not grouped yet
+     */
+
     /**
      * @test
      */