4b: Test it returns blog posts

web/modules/custom/my_module/tests/src/Kernel/ArticleRepositoryTest.php

@@ -0,0 +1,14 @@
+<?php
+
+namespace Drupal\Tests\my_module\Kernel;
+
+use Drupal\KernelTests\Core\Entity\EntityKernelTestBase;
+
+class ArticleRepositoryTest extends EntityKernelTestBase {
+
+  /** @test */
+  public function it_returns_blog_posts() {
+    $this->assertCount(1, $articles);
+  }
+
+}