[TASK] Add assertInstanceOf tests for CSSListItem

These should probably have been added as part of #1212.
They confirm that the various types supplanted by `CSSListItem` in the API all
implement the new interface.

Resolves #1236.

Author: JakeQZ

tests/Unit/CSSList/AtRuleBlockListTest.php

@@ -9,6 +9,7 @@
 use Sabberworm\CSS\CSSList\AtRuleBlockList;
 use Sabberworm\CSS\CSSList\CSSBlockList;
 use Sabberworm\CSS\CSSList\CSSList;
+use Sabberworm\CSS\CSSList\CSSListItem;
 use Sabberworm\CSS\Renderable;
 
 /**
@@ -48,6 +49,16 @@ public function implementsCommentable(): void
         self::assertInstanceOf(Commentable::class, $subject);
     }
 
+    /**
+     * @test
+     */
+    public function implementsCSSListItem(): void
+    {
+        $subject = new AtRuleBlockList('supports');
+
+        self::assertInstanceOf(CSSListItem::class, $subject);
+    }
+
     /**
      * @test
      */

tests/Unit/CSSList/CSSListTest.php

@@ -6,6 +6,7 @@
 
 use PHPUnit\Framework\TestCase;
 use Sabberworm\CSS\Comment\Commentable;
+use Sabberworm\CSS\CSSList\CSSListItem;
 use Sabberworm\CSS\Renderable;
 use Sabberworm\CSS\RuleSet\DeclarationBlock;
 use Sabberworm\CSS\Tests\Unit\CSSList\Fixtures\ConcreteCSSList;
@@ -35,6 +36,16 @@ public function implementsCommentable(): void
         self::assertInstanceOf(Commentable::class, $subject);
     }
 
+    /**
+     * @test
+     */
+    public function implementsCSSListItem(): void
+    {
+        $subject = new ConcreteCSSList();
+
+        self::assertInstanceOf(CSSListItem::class, $subject);
+    }
+
     /**
      * @test
      */

tests/Unit/CSSList/KeyFrameTest.php

@@ -7,6 +7,7 @@
 use PHPUnit\Framework\TestCase;
 use Sabberworm\CSS\Comment\Commentable;
 use Sabberworm\CSS\CSSList\CSSList;
+use Sabberworm\CSS\CSSList\CSSListItem;
 use Sabberworm\CSS\CSSList\KeyFrame;
 use Sabberworm\CSS\Property\AtRule;
 use Sabberworm\CSS\Renderable;
@@ -47,6 +48,16 @@ public function implementsCommentable(): void
         self::assertInstanceOf(Commentable::class, $subject);
     }
 
+    /**
+     * @test
+     */
+    public function implementsCSSListItem(): void
+    {
+        $subject = new KeyFrame();
+
+        self::assertInstanceOf(CSSListItem::class, $subject);
+    }
+
     /**
      * @test
      */

tests/Unit/Property/CSSNamespaceTest.php

@@ -0,0 +1,34 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Sabberworm\CSS\Tests\Unit\Property;
+
+use PHPUnit\Framework\TestCase;
+use Sabberworm\CSS\CSSList\CSSListItem;
+use Sabberworm\CSS\Property\CSSNamespace;
+use Sabberworm\CSS\Value\CSSString;
+
+/**
+ * @covers \Sabberworm\CSS\Property\CSSNamespace
+ */
+final class CSSNamespaceTest extends TestCase
+{
+    /**
+     * @var CSSNamespace
+     */
+    private $subject;
+
+    protected function setUp(): void
+    {
+        $this->subject = new CSSNamespace(new CSSString('http://www.w3.org/2000/svg'));
+    }
+
+    /**
+     * @test
+     */
+    public function implementsCSSListItem(): void
+    {
+        self::assertInstanceOf(CSSListItem::class, $this->subject);
+    }
+}

tests/Unit/Property/CharsetTest.php

@@ -0,0 +1,34 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Sabberworm\CSS\Tests\Unit\Property;
+
+use PHPUnit\Framework\TestCase;
+use Sabberworm\CSS\CSSList\CSSListItem;
+use Sabberworm\CSS\Property\Charset;
+use Sabberworm\CSS\Value\CSSString;
+
+/**
+ * @covers \Sabberworm\CSS\Property\Charset
+ */
+final class CharsetTest extends TestCase
+{
+    /**
+     * @var Charset
+     */
+    private $subject;
+
+    protected function setUp(): void
+    {
+        $this->subject = new Charset(new CSSString('UTF-8'));
+    }
+
+    /**
+     * @test
+     */
+    public function implementsCSSListItem(): void
+    {
+        self::assertInstanceOf(CSSListItem::class, $this->subject);
+    }
+}

tests/Unit/Property/ImportTest.php

@@ -0,0 +1,35 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Sabberworm\CSS\Tests\Unit\Property;
+
+use PHPUnit\Framework\TestCase;
+use Sabberworm\CSS\CSSList\CSSListItem;
+use Sabberworm\CSS\Property\Import;
+use Sabberworm\CSS\Value\CSSString;
+use Sabberworm\CSS\Value\URL;
+
+/**
+ * @covers \Sabberworm\CSS\Property\Import
+ */
+final class ImportTest extends TestCase
+{
+    /**
+     * @var Import
+     */
+    private $subject;
+
+    protected function setUp(): void
+    {
+        $this->subject = new Import(new URL(new CSSString('https://example.org/')), null);
+    }
+
+    /**
+     * @test
+     */
+    public function implementsCSSListItem(): void
+    {
+        self::assertInstanceOf(CSSListItem::class, $this->subject);
+    }
+}

tests/Unit/RuleSet/AtRuleSetTest.php

@@ -0,0 +1,33 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Sabberworm\CSS\Tests\Unit\RuleSet;
+
+use PHPUnit\Framework\TestCase;
+use Sabberworm\CSS\CSSList\CSSListItem;
+use Sabberworm\CSS\RuleSet\AtRuleSet;
+
+/**
+ * @covers \Sabberworm\CSS\RuleSet\AtRuleSet
+ */
+final class AtRuleSetTest extends TestCase
+{
+    /**
+     * @var AtRuleSet
+     */
+    private $subject;
+
+    protected function setUp(): void
+    {
+        $this->subject = new AtRuleSet('supports');
+    }
+
+    /**
+     * @test
+     */
+    public function implementsCSSListItem(): void
+    {
+        self::assertInstanceOf(CSSListItem::class, $this->subject);
+    }
+}

tests/Unit/RuleSet/DeclarationBlockTest.php

@@ -0,0 +1,33 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Sabberworm\CSS\Tests\Unit\RuleSet;
+
+use PHPUnit\Framework\TestCase;
+use Sabberworm\CSS\CSSList\CSSListItem;
+use Sabberworm\CSS\RuleSet\DeclarationBlock;
+
+/**
+ * @covers \Sabberworm\CSS\RuleSet\DeclarationBlock
+ */
+final class DeclarationBlockTest extends TestCase
+{
+    /**
+     * @var DeclarationBlock
+     */
+    private $subject;
+
+    protected function setUp(): void
+    {
+        $this->subject = new DeclarationBlock();
+    }
+
+    /**
+     * @test
+     */
+    public function implementsCSSListItem(): void
+    {
+        self::assertInstanceOf(CSSListItem::class, $this->subject);
+    }
+}

tests/Unit/RuleSet/Fixtures/ConcreteRuleSet.php

@@ -0,0 +1,19 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Sabberworm\CSS\Tests\Unit\RuleSet\Fixtures;
+
+use Sabberworm\CSS\OutputFormat;
+use Sabberworm\CSS\RuleSet\RuleSet;
+
+final class ConcreteRuleSet extends RuleSet
+{
+    /**
+     * @return never
+     */
+    public function render(OutputFormat $outputFormat): string
+    {
+        throw new \BadMethodCallException('Nothing to see here :/', 1744067015);
+    }
+}

tests/Unit/RuleSet/RuleSetTest.php

@@ -0,0 +1,33 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Sabberworm\CSS\Tests\Unit\RuleSet;
+
+use PHPUnit\Framework\TestCase;
+use Sabberworm\CSS\CSSList\CSSListItem;
+use Sabberworm\CSS\Tests\Unit\RuleSet\Fixtures\ConcreteRuleSet;
+
+/**
+ * @covers \Sabberworm\CSS\RuleSet\RuleSet
+ */
+final class RuleSetTest extends TestCase
+{
+    /**
+     * @var ConcreteRuleSet
+     */
+    private $subject;
+
+    protected function setUp(): void
+    {
+        $this->subject = new ConcreteRuleSet();
+    }
+
+    /**
+     * @test
+     */
+    public function implementsCSSListItem(): void
+    {
+        self::assertInstanceOf(CSSListItem::class, $this->subject);
+    }
+}