Skip to main content

Yoast SEO Development: Set up integration tests

In order to run the integration tests in any of our WordPress plugins, you need the following:

  1. Access to PHP with the version that you want to test with.
  2. A copy of the wordpress-develop repository that includes the base-testcases.
  3. A MySQL server with an empty database.

Install PHP

If you haven't already, you can install PHP on your machine by following the PHP installation docs. You could also choose to run the tests with a Docker container if for whatever reason you can't/don't want to install PHP locally, but that process is not documented here.

Clone the wordpress-develop repository

Clone WordPress/wordpress-develop. The integration tests load WordPress and all its functions and API's from this clone when you start your integration tests. This means that this allows us to test against your locally installed version of WordPress, which is the 'integration' part. It also provides some utility classes (e.g. the test-cases) for our own tests.

Setup up the MySQL server

There are a lot of ways in which you can satisfy this requirement. Here we outline a couple of options that the Yoast teams like to use. You can pick either one of them, depending on your personal needs/preference.

Option 1: Using the MySQL server provided by the wordpress-develop Docker environment

An added bonus of this option is that you also have a separate setup for writing patches and unit tests for WordPress itself.

Expose the Docker MySQL instance

We'll expose the Docker MySQL instance locally so PHPUnit tests can access it.

Expose MySQL port

In your local copy of wordpress-develop that you cloned before, you have to expose the MySQL port, which allows us to connect to it later on.

In wordpress-develop, copy the docker-compose.yml to docker-compose.override.yml, and open the override file. Then change:

- "3306"


- "3306:3306"

This will expose the port to the local environment.

Edit your hosts file

Edit your hosts file by running sudo nano /etc/hosts in your terminal and add the following: localhost mysql

Making your database accessible

To make your database accessible, run the following command:

  • on Mac:
sudo ifconfig lo0 alias
  • on Linux:
sudo ifconfig lo:0
  • on Windows:
netsh interface ipv4 add address "Loopback Pseudo-Interface 1"

Spin up the containers

If you've gone through all the above steps, it's time to start the containers!

In your terminal, run the following commands:

npm install
npm run build:dev
npm run env:start
npm run env:install

When you want to stop the containers, you simply can do:

npm run env:stop

Option 2: Using the MySQL server provided by your Local by Flywheel dev environment

If you use Local for development, this could be an easy alternative.

  1. Start your development site in Local.
  2. Switch to the "Database" tab.
  3. Here, you should see an "Open Adminer" link. Click it.
  4. In Adminer, near the top-left there is a "SQL command" link. Click it.
  5. In the textarea enter CREATE DATABASE `plugins-integration-test` and click "Execute".

Now you have your database, now we need to tell the test suite how to connect to it:

  1. In your wordpress-develop clone, find the wp-tests-config.php file. If it doesn't exist yet, copy wp-tests-config-sample.php and name it wp-tests-config.php.
  2. Find the block that looks like this
        define( 'DB_NAME', 'youremptytestdbnamehere' );
    define( 'DB_USER', 'yourusernamehere' );
    define( 'DB_PASSWORD', 'yourpasswordhere' );
    define( 'DB_HOST', 'localhost' );
    define( 'DB_CHARSET', 'utf8' );
    define( 'DB_COLLATE', '' );
  3. Change the DB_NAME value to plugins-integration-test.
  4. Change the values for DB_USER, DB_PASSWORD and DB_HOST to the values that are listed in the "Database" tab of your Local by Flywheel site.

Tying it all together

The last step is to tie it together with your wordpress-seo cloned repository.

To do this, please ensure you've followed the steps regarding setting up PHPUnit and start running the tests.


Conflicting MySQL connections

If you get errors about the database connection, make sure other no MySQL processes are running in the background by running brew services stop mysql in your terminal.

Accessing the admin (wordpress-develop docker)

The Docker setup actually runs a complete local WordPress site. For debugging purposes you can access the admin of this testing environment. By default, the credentials to access the WordPress admin, are:

  • Host - http://localhost:8889/wp-admin
  • Username - admin
  • Password - password

Accessing the database (wordpress-develop docker)

In case you need to access the database to check something (i.e. whether or not all database tables have been created), you can use the following credentials in your database tool of choice:

  • Host -
  • Username - root
  • Password - password
  • Database - wordpress_develop
  • Port - 3306