Integration Tests

Integration tests, are a bit tricky to set up.

The following needs to happen in order to successfully run them:

1. Load WordPress
2. Replace the default TestCase class with another with enhanced WordPress functionalities (e.g. to easily create users or posts)
3. Create the REST server and boot it using the rest_api_init hook

wp-pest to the rescue 🦸

However, thanks to wp-pest most of this trouble is no longer an issue. By simply running the command bellow, it will automatically pull the WordPress version you want and also set up the tests directory for you.

./vendor/bin/wp-pest setup plugin --plugin-slug my-plugin --wp-version 6.4.4

Tip

If you use matapatos/wp-fastendpoints-my-plugin you can use the already configured composer setup:wp:6.x commands

Optional changes

If you take a closer look at the resultant tests structure you might notice that is slightly different from matapatos/wp-fastendpoints-my-plugin. These changes are not mandatory and so, feel free to skip this section ⏩

The main reason of these differences is to allow us to run tests without the need to always specify a group of tests. Those changes include:

/**
* tests/Helpers.php
 */ 
namespace MyPlugin\Tests;

class Helpers
{
    /**
     * Checks if weather we want to run integration tests or not
     */
    public static function isIntegrationTest(): bool
    {
        return isset($GLOBALS['argv']) && in_array('--group=integration', $GLOBALS['argv'], true);
    }
}

/**
* tests/Integration/*Test.php
 */ 
namespace MyPlugin\Tests\Integration;

use MyPlugin\Tests\Helpers;

// Needs to add this check to every Integration test file
if (! Helpers::isIntegrationTest()) {
    return;
}

Our integration test 🙃

Now that everything is configured we can start creating integration tests:

test('Create a new post', function () {
    // Create user with correct permissions
    $userId = $this::factory()->user->create();
    $user = get_user_by('id', $userId);
    $user->add_cap('publish_posts');
    // Make request as that user
    wp_set_current_user($userId);
    $request = new \WP_REST_Request('POST', '/my-plugin/v1/posts');
    $request->set_body_params([
        'post_title' => 'My testing message',
        'post_status' => 'publish',
        'post_type' => 'post',
        'post_content' => '<p>Message body</p>',
    ]);
    $response = $this->server->dispatch($request);
    expect($response->get_status())->toBe(201);
    $postId = $response->get_data();
    // Check that the post details are correct
    expect(get_post($postId))
        ->toBeInstanceOf(\WP_Post::class)
        ->toHaveProperty('post_title', 'My testing message')
        ->toHaveProperty('post_status', 'publish')
        ->toHaveProperty('post_type', 'post')
        ->toHaveProperty('post_content', '<p>Message body</p>');
})->group('api', 'posts');

Here, we take advantage of the existent testing factories to create a single user with the necessary capability to publish posts. Then, we make mimic a REST request from that given user, and lastly, we check if that blog post was created.