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 one which eases testing in WordPress (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. Via a simple command it solves most of the troubles for us! 😎

# Installs wp-pest
composer require dingo-d/wp-pest --dev

# Set's up WP
./vendor/bin/wp-pest setup plugin --plugin-slug my-plugin --wp-version 6.8.2

Tip

If you use attributes-php/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 attributes-php/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

<?php
declare(strict_types=1);

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/PostsApiTest.php

<?php
declare(strict_types=1);

namespace MyPlugin\Tests\Integration;

use MyPlugin\Tests\Helpers;

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

SetUp and TearDown

The last step before creating our integration tests, is to set up the REST server and trigger the *rest_api_init* hook.

tests/Integration/PostsApiTest.php

<?php
beforeEach(function () {
    parent::setUp();

    // Set up a REST server instance.
    global $wp_rest_server;
    $this->server = $wp_rest_server = new WP_REST_Server;
    do_action('rest_api_init', $this->server);
});

afterEach(function () {
    global $wp_rest_server;
    $this->server = $wp_rest_server = null;

    parent::tearDown();
});

Our integration test 🙃

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

tests/Integration/PostsApiTest.php

<?php
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_author' => $userId,
    ]);
    $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_author', $userId);
})->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 mimic a REST request from that given user, and lastly, we check if that blog post was created.