Test-driven development & Testing

You can see some official documentation on Drupal testing to start. 

See also test-driven Drupal development in the Drupal at your Fingertips book.

Writing tests is not as difficult as it seems! The first step seems to be the hardest. Let's write a single, simple test to be soundly on our way of practicing test-driven development!

But first, let's set up the environment. It's relatively simple - although to be safe, I just might have two local instances of the drupal docker setup, to not pollute my production setup with development-grade dependencies. 

The dependencies are defined in composer.json and they are, phpunit, core-dev and mink. I have outlined the development-grade setup on my wiki and here it is pasted again:

 composer require --dev --no-update symfony/filesystem:4.4.42
 composer require --dev drupal/core-dev:9.5.11 --with-all-dependencies
   composer require --dev behat/mink jcalderonzumba/mink-phantomjs-driver
   composer update -W
   composer update symfony/filesystem:4.4.42 drush/drush -W
   composer require --dev drupal/core-dev -W
   composer require --dev phpspec/prophecy-phpunit:^2

You'd have a copy of phpunit.xml and edit it appropriately. Then you'll be able to run your tests:

cd /var/www/html # that's where my composer.json is
cp web/core/phpunit.xml.dist .
./vendor/bin/phpunit web/modules/ish_drupal_module/tests/src/Functional/UserProfileAnonymousAccessTest.php

Now then, let's write a test, say, assert that a user profile is view-able by an anonymous user. As suggested by GPT, and you can view the same file on github: 

// modules/my_module/tests/src/Functional/UserProfileAnonymousAccessTest.php
<?php

namespace Drupal\Tests\ish_drupal_module\Functional;

use Drupal\Tests\BrowserTestBase;
use Drupal\user\Entity\User;

/**
 * Tests anonymous access to user profile pages.
 *
 * @group ish_drupal_module
 */
class UserProfileAnonymousAccessTest extends BrowserTestBase {

  /**
   * {@inheritdoc}
   */
  protected static $modules = [
    'user',
  ];

  /**
   * Test that anonymous users can view user profiles.
   */
  public function testAnonymousCanViewUserProfile(): void {
    // Create a user account.
    $account = User::create([
      'name' => 'public_user',
      'mail' => 'public@example.com',
      'status' => 1,
    ]);
    $account->save();

    // Grant anonymous users permission to view user information.
    $anonymous_role = $this->container
      ->get('entity_type.manager')
      ->getStorage('user_role')
      ->load('anonymous');

    $anonymous_role->grantPermission('access user profiles');
    $anonymous_role->save();

    // Clear caches so permission changes apply.
    $this->container->get('cache_tags.invalidator')->invalidateTags(['config:user.role.anonymous']);

    // Visit the user profile as anonymous.
    $this->drupalGet('/user/' . $account->id());

    // Assert HTTP 200.
    $this->assertSession()->statusCodeEquals(200);

    // Assert the page is not access denied.
    $this->assertSession()->pageTextNotContains('Access denied');

    // Assert username is visible.
    $this->assertSession()->pageTextContains('public_user');
  }

}

.

.^.