Add HeaderBlock for slack notifier

src/Symfony/Component/Notifier/Bridge/Slack/Block/SlackHeaderBlock.php

@@ -0,0 +1,51 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Notifier\Bridge\Slack\Block;
+
+use Symfony\Component\Notifier\Exception\LogicException;
+
+/**
+ * @author Tomas Norkūnas <norkunas.tom@gmail.com>
+ *
+ * @experimental in 5.3
+ */
+final class SlackHeaderBlock extends AbstractSlackBlock
+{
+    private const TEXT_LIMIT = 150;
+    private const ID_LIMIT = 255;
+
+    public function __construct(string $text)
+    {
+        if (\strlen($text) > self::TEXT_LIMIT) {
+            throw new LogicException(sprintf('Maximum length for the text is %d characters.', self::TEXT_LIMIT));
+        }
+
+        $this->options = [
+            'type' => 'header',
+            'text' => [
+                'type' => 'plain_text',
+                'text' => $text,
+            ],
+        ];
+    }
+
+    public function id(string $id): self
+    {
+        if (\strlen($id) > self::ID_LIMIT) {
+            throw new LogicException(sprintf('Maximum length for the block id is %d characters.', self::ID_LIMIT));
+        }
+
+        $this->options['block_id'] = $id;
+
+        return $this;
+    }
+}

src/Symfony/Component/Notifier/Bridge/Slack/CHANGELOG.md

@@ -5,6 +5,7 @@ CHANGELOG
 -----
 
  * Check for maximum number of buttons in Slack action block
+ * Add HeaderBlock
 
 5.2.0
 -----

src/Symfony/Component/Notifier/Bridge/Slack/Tests/Block/SlackHeaderBlockTest.php

@@ -0,0 +1,51 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Notifier\Bridge\Slack\Tests\Block;
+
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\Notifier\Bridge\Slack\Block\SlackHeaderBlock;
+use Symfony\Component\Notifier\Exception\LogicException;
+
+final class SlackHeaderBlockTest extends TestCase
+{
+    public function testCanBeInstantiated(): void
+    {
+        $header = new SlackHeaderBlock('header text');
+        $header->id('header_id');
+
+        $this->assertSame([
+            'type' => 'header',
+            'text' => [
+                'type' => 'plain_text',
+                'text' => 'header text',
+            ],
+            'block_id' => 'header_id',
+        ], $header->toArray());
+    }
+
+    public function testThrowsWhenTextExceedsCharacterLimit(): void
+    {
+        $this->expectException(LogicException::class);
+        $this->expectExceptionMessage('Maximum length for the text is 150 characters.');
+
+        new SlackHeaderBlock(str_repeat('h', 151));
+    }
+
+    public function testThrowsWhenBlockIdExceedsCharacterLimit(): void
+    {
+        $this->expectException(LogicException::class);
+        $this->expectExceptionMessage('Maximum length for the block id is 255 characters.');
+
+        $header = new SlackHeaderBlock('header');
+        $header->id(str_repeat('h', 256));
+    }
+}