Add lesson 3

- Add failing blog page test.
- Add custom routing, need to create Controller.
- Add BlogPageController.
- Test posts are visible.

web/modules/custom/example/example.info.yml

@@ -0,0 +1,3 @@
+name: Example
+type: module
+core_version_requirement: ^10

web/modules/custom/example/example.routing.yml

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+example.blog:
+  path: /blog
+  defaults:
+    _controller: Drupal\example\Controller\BlogPageController
+    _title: Blog
+  requirements:
+    _permission: access content

web/modules/custom/example/src/Controller/BlogPageController.php

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+<?php
+
+namespace Drupal\example\Controller;
+
+use Drupal\Core\Controller\ControllerBase;
+
+class BlogPageController extends ControllerBase {
+
+  public function __invoke(): array {
+    $nodeStorage = $this->entityTypeManager()->getStorage('node');
+    $nodes = $nodeStorage->loadMultiple();
+
+    $build = [];
+    $build['content']['#theme'] = 'item_list';
+    foreach ($nodes as $node) {
+      $build['content']['#items'][] = $node->label();
+    }
+
+    return $build;
+  }
+
+}

web/modules/custom/example/tests/src/Functional/BlogPageTest.php

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+<?php
+
+namespace Drupal\Tests\example\Functional;
+
+use Drupal\Tests\BrowserTestBase;
+use Symfony\Component\HttpFoundation\Response;
+
+class BlogPageTest extends BrowserTestBase {
+
+  protected $defaultTheme = 'stark';
+
+  protected static $modules = ['node', 'example'];
+
+  public function testBlogPage(): void {
+    $this->drupalGet('/blog');
+
+    $this->assertSession()->statusCodeEquals(Response::HTTP_OK);
+  }
+
+  public function testPostsAreVisible(): void {
+    $this->createNode(['type' => 'post', 'title' => 'First post']);
+    $this->createNode(['type' => 'post', 'title' => 'Second post']);
+    $this->createNode(['type' => 'post', 'title' => 'Third post']);
+
+    $this->drupalGet('/blog');
+
+    $assert = $this->assertSession();
+    $assert->pageTextContains('First post');
+    $assert->pageTextContains('Second post');
+    $assert->pageTextContains('Third post');
+  }
+
+}