// start test
/** @test */
public function it_loads_the_blog_page(): void {
  $this->drupalGet('/blog');

  $session = $this->assertSession();
  $session->statusCodeEquals(200);

  $session->responseContains('<h1>Blog</h1>');
  $session->pageTextContains('Welcome to my blog!');
}
// end test

E                                                                   1 / 1 (100%)

Time: 00:02.101, Memory: 6.00 MB

// start output
There was 1 error:

1) Drupal\Tests\drupalcon\Functional\BlogPageTest::it_loads_the_blog_page
Behat\Mink\Exception\ResponseTextException:
The text "Welcome to my blog!" was not found anywhere in the text
of the current page.
// end output

/app/vendor/behat/mink/src/WebAssert.php:907
/app/vendor/behat/mink/src/WebAssert.php:293
/app/web/modules/custom/drupalcon/tests/src/Functional/BlogPageTest.php:17
/app/vendor/phpunit/phpunit/src/Framework/TestResult.php:728

ERRORS!
Tests: 1, Assertions: 3, Errors: 1.

// start code
namespace Drupal\drupalcon\Controller;

use Drupal\Core\StringTranslation\StringTranslationTrait;

class BlogPageController {

  use StringTranslationTrait;

  public function __invoke(): array {
    return [
      '#markup' => $this->t('Welcome to my blog!'),
    ];
  }

}
// end code

// start output2
.                                                                   1 / 1 (100%)

Time: 00:01.911, Memory: 6.00 MB

OK (1 test, 3 assertions)
// end output2

Task completed in 0m2.124s