[CLEANUP] Reorder and group some tests for CSSList

This is a pre-patch to having dedicated tests for some of our
abstract classes in order to avoid duplicated tests.

This change merely moves tests around in the test classes
(and fixing two incorrectly named tests), but does not
change the tests themselves in any way.

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);
     }
 
+    /*
+     * Tests for the constructor and its parameters
+     */
+
     /**
      * @test
      */
@@ -58,15 +66,9 @@ public function atRuleNameReturnsTypeProvidedToConstructor(): void
         self::assertSame($type, $subject->atRuleName());
     }
 
-    /**
-     * @test
+    /*
+     * Tests for functionality implemented by the tested class itself
      */
-    public function getLineNoByDefaultReturnsZero(): void
-    {
-        $subject = new AtRuleBlockList('supports');
-
-        self::assertSame(0, $subject->getLineNo());
-    }
 
     /**
      * @test
@@ -93,22 +95,40 @@ public function atRuleArgsReturnsArgumentsProvidedToConstructor(): void
     /**
      * @test
      */
-    public function getLineNoReturnsLineNumberProvidedToConstructor(): void
+    public function isRootListAlwaysReturnsFalse(): void
     {
-        $lineNumber = 42;
-
-        $subject = new AtRuleBlockList('', '', $lineNumber);
+        $subject = new AtRuleBlockList('supports');
 
-        self::assertSame($lineNumber, $subject->getLineNo());
+        self::assertFalse($subject->isRootList());
     }
 
+    /*
+     * Tests for functionality implemented in `CSSBlockList`
+     */
+
+    /*
+     * Tests for functionality implemented in `CSSList`
+     */
+
     /**
      * @test
      */
-    public function isRootListAlwaysReturnsFalse(): void
+    public function getLineNoByDefaultReturnsZero(): void
     {
         $subject = new AtRuleBlockList('supports');
 
-        self::assertFalse($subject->isRootList());
+        self::assertSame(0, $subject->getLineNo());
+    }
+
+    /**
+     * @test
+     */
+    public function getLineNoReturnsLineNumberProvidedToConstructor(): void
+    {
+        $lineNumber = 42;
+
+        $subject = new AtRuleBlockList('', '', $lineNumber);
+
+        self::assertSame($lineNumber, $subject->getLineNo());
     }
 }