Drupal Best Practices: Testing for Stability and Reliability

Testing is a crucial part of any development process, and Drupal is no exception. With complex websites and content management systems like Drupal, maintaining stability, functionality, and reliability is essential as your site evolves. Without a solid testing strategy, new features, updates, or bug fixes could unintentionally break existing functionality, leading to poor user experience, security vulnerabilities, and additional development costs.

In this blog post, we’ll explore the key testing best practices for Drupal:

1. Automated Testing: Implement automated tests using Drupal’s built-in testing framework or PHPUnit for functional, unit, and behavioral testing.
2. Continuous Integration (CI): Set up a CI pipeline to automatically run tests on every commit and deployment, ensuring code quality and stability.

By following these practices, you can ensure that your Drupal site remains stable and secure while enabling continuous development and rapid deployment of new features.

---

Automated Testing in Drupal

Automated testing is the practice of writing tests that are executed automatically to verify the behavior of your code. In Drupal, automated testing helps you ensure that both custom and core functionality works as expected and that new changes don’t break existing functionality.

Why Automated Testing is Essential for Drupal

1. Prevent Regressions: Automated tests catch regressions—issues introduced when new code changes affect previously working features—before they reach production.
2. Improve Code Quality: Writing tests forces you to think about how your code works and how it should behave, leading to cleaner, more maintainable code.
3. Faster Development: Automated tests speed up development by allowing you to quickly verify whether your code is functioning correctly without needing to manually test every feature after each change.
4. Supports Continuous Integration: Automated tests are essential for continuous integration pipelines, which ensure that code is tested on every commit and merge before deployment.

Types of Automated Tests in Drupal

Drupal supports several types of automated tests, each serving different purposes:

1. Unit Tests: Focus on testing individual functions or methods in isolation. Unit tests help ensure that the smallest pieces of functionality are working as expected, without relying on external systems like the database or file system.
2. Functional Tests: Test how the system behaves from an end-user perspective, interacting with pages and verifying that the expected output is displayed. These tests simulate real-world user actions and are particularly useful for testing form submissions, page loads, and user interactions.
3. Behavioral Tests: These are higher-level tests that verify the behavior of your system from a user’s perspective. Tools like Behat allow you to write human-readable tests that simulate user workflows, such as logging in, submitting a form, or navigating between pages.
4. Integration Tests: Ensure that different parts of your Drupal system (such as custom modules, APIs, and third-party services) interact correctly. Integration tests help catch issues where individual components work fine in isolation but fail when combined.

Implementing Automated Testing in Drupal

1. Using Drupal’s Built-In Testing Framework

Drupal comes with a built-in testing framework that supports functional, unit, and kernel tests. You can write your tests using PHPUnit, which is the default testing framework in Drupal 8 and beyond.

To run tests in Drupal, follow these steps:

• Set up PHPUnit: Ensure PHPUnit is installed in your Drupal project. You can install it via Composer:

  composer require --dev phpunit/phpunit

• Create a Test Class: Place your test classes in the tests/src directory of your custom module. Example of a simple unit test:

  namespace Drupal\Tests\mymodule\Unit;

  use Drupal\Tests\UnitTestCase;

  /**
   * Tests for my custom functionality.
   *
   * @group mymodule
   */
  class MyCustomTest extends UnitTestCase {

    public function testMyFunction() {
      $result = mymodule_myfunction();
      $this->assertEquals('expected_value', $result);
    }
  }

• Run Your Tests: Use the following Drush command to run tests:

  drush test-run mymodule

2. Writing Functional Tests

Functional tests are essential for verifying that your site works as expected from an end-user’s perspective. In Drupal, functional tests use a headless browser to simulate user actions, such as filling out forms, submitting data, and navigating pages.

Example of a functional test:

namespace Drupal\Tests\mymodule\Functional;

use Drupal\Tests\BrowserTestBase;

/**
 * Functional test for mymodule.
 *
 * @group mymodule
 */
class MyCustomFunctionalTest extends BrowserTestBase {

  /**
   * Modules to enable.
   *
   * @var array
   */
  protected static $modules = ['mymodule'];

  /**
   * Test form submission.
   */
  public function testFormSubmission() {
    $this->drupalGet('/myform');
    $this->assertSession()->statusCodeEquals(200);

    $edit = [
      'name' => 'Test User',
      'email' => '[email protected]',
    ];
    $this->submitForm($edit, 'Submit');
    $this->assertSession()->pageTextContains('Thank you for submitting the form.');
  }
}

This test ensures that a custom form works correctly, and that submitting the form displays the appropriate confirmation message.

3. Behavioral Testing with Behat

Behat is a great tool for writing behavioral tests in human-readable language, following Behavior-Driven Development (BDD) principles. Behat allows you to define scenarios that test specific user interactions.

To get started with Behat, follow these steps:

1. Install Behat:

   composer require --dev drupal/drupal-extension

2. Write a Behat Test Scenario: Create a feature file with the following scenario:

   Feature: Submit contact form
     In order to contact the site administrators
     As a site visitor
     I want to submit the contact form

   Scenario: Submit a valid contact form
     Given I am on "/contact"
     When I fill in "Your name" with "John Doe"
     And I fill in "Your email address" with "[email protected]"
     And I press "Send message"
     Then I should see "Your message has been sent"

3. Run the Behat Test: Use the following command to run Behat tests:

   vendor/bin/behat

Behat is particularly useful for testing user workflows and ensuring that key site functionalities are working as expected from a non-technical perspective.

---

Continuous Integration (CI): Automating Testing with Every Commit

Automating your tests is crucial to ensure that your code is always in a deployable state. By setting up a Continuous Integration (CI) pipeline, you can automatically run tests every time new code is committed, merged, or deployed. This process helps catch bugs early, reduces the risk of regressions, and ensures that your site remains stable and secure.

Why CI is Essential for Drupal Development

1. Automated Testing on Every Commit: With CI, you can automatically run your test suite whenever code is pushed to a repository. This helps identify issues early in the development process before they affect production.
2. Ensures Code Quality: CI pipelines can be configured to run not only automated tests but also code quality checks, such as linting, coding standards enforcement, and static analysis.
3. Faster Feedback Loop: Developers get immediate feedback when something breaks, allowing them to fix issues quickly and keep the project moving forward.
4. Minimized Human Error: Automating tests reduces the reliance on manual testing, which is time-consuming and error-prone.

Setting Up CI for Drupal Projects

There are several CI tools available that integrate seamlessly with Drupal projects, including GitHub Actions, CircleCI, Travis CI, and GitLab CI. Below is an example of how you can set up a CI pipeline using GitHub Actions to automate testing for a Drupal project.

Example: GitHub Actions CI for Drupal

1. Create a GitHub Actions Workflow File: Inside your repository, create a file named .github/workflows/test.yml with the following configuration:

   name: Run Drupal Tests

   on:
     push:
       branches:
         - main
     pull_request:
       branches:
         - main

   jobs:
     build:
       runs-on: ubuntu-latest

       steps:
       - name: Checkout code
         uses: actions/checkout@v2

       - name: Set up PHP
         uses: shivammathur/setup-php@v2
         with:
           php-version: '7.4'

       - name: Install Composer dependencies
         run: composer install --prefer-dist --no-progress --no-suggest

       - name: Run Unit Tests
         run: ./vendor/bin/phpunit --group=unit

       - name: Run Functional Tests
         run: ./vendor/bin/phpunit --group=functional

2. Trigger Tests on Push or Pull Request: This workflow triggers whenever code is pushed or a pull request is opened on the main branch. It checks out the code, installs the required dependencies, and runs both unit and functional tests.
3. Monitor Results: When the workflow is triggered, GitHub Actions will display the results of your tests directly within the pull request interface, allowing developers to easily see whether their changes pass the tests.

Running Automated Tests on Every Deployment

For more advanced workflows, you can extend your CI pipeline to automatically deploy code to a

staging environment after passing all tests. Tools like Jenkins, GitLab CI/CD, or Travis CI allow you to set up complex pipelines that handle testing, quality checks, and deployments.

---

Conclusion

Testing is a critical part of Drupal development, helping to ensure that your site remains stable, secure, and reliable as new features are added or updates are applied. By implementing automated testing—whether through Drupal’s built-in framework, PHPUnit, or Behat—you can reduce the risk of regressions and improve the overall quality of your code.

Integrating Continuous Integration (CI) ensures that tests are automatically run on every commit and deployment, providing immediate feedback and reducing the time needed for manual testing.

By adopting these testing best practices, you’ll build a more resilient and reliable Drupal site, ensuring smoother deployments, fewer bugs, and a better user experience.