// start code
// tests/src/ArticleRepositoryTest.php

namespace Drupal\Tests\drupalcon\Kernel;

use Drupal\KernelTests\Core\Entity\EntityKernelTestBase;

class ArticleRepositoryTest extends EntityKernelTestBase {

  /** @test */
  public function it_returns_blog_posts(): void {
    $repository = $this->container->get(ArticleRepository::class);

    $articles = $repository->getAll();

    $this->assertCount(1, $articles);
  }
// end code

}

---

// start output
E                                                                   1 / 1 (100%)

Time: 00:00.405, Memory: 6.00 MB

There was 1 error:

1) Drupal\Tests\drupalcon\Kernel\ArticleRepositoryTest::it_returns_blog_posts
Symfony\Component\DependencyInjection\Exception\ServiceNotFoundException:
You have requested a non-existent service
"Drupal\Tests\drupalcon\Kernel\ArticleRepository".
// end output

/app/vendor/symfony/dependency-injection/ContainerBuilder.php:992
/app/vendor/symfony/dependency-injection/ContainerBuilder.php:568
/app/vendor/symfony/dependency-injection/ContainerBuilder.php:531
/app/web/modules/custom/drupalcon/tests/src/ArticleRepositoryTest.php:11
/app/vendor/phpunit/phpunit/src/Framework/TestResult.php:728

ERRORS!
Tests: 1, Assertions: 4, Errors: 1.

Time: 00:00.409, Memory: 8.00 MB