This sample plugin contains a basic meta box for storing a byline, as well as unit tests for testing the entire plugin.

• Check your PHP version in your terminal php --version. Unit tests need PHP 7, in case you need to upgrade.
• Additional info for the following: https://foresthoffman.com/running-wordpress-phpunit-tests-with-docker/
• Make a new directory and clone the WordPress develop repo: git clone [email protected]:WordPress/wordpress-develop.git
• Inside the root of the cloned wordpress-develop directory, copy the wp-tests-config-sample.php file to wp-tests-config.php and modify the DB_NAME, DB_USER, DB_PASSWORD, DB_HOST, and WP_TESTS_DOMAIN, example:

define( 'DB_USER', 'root' );
define( 'DB_PASSWORD', 'password' );
define( 'DB_HOST', '127.0.0.1:3308' ); // Match the port number to Docker.
define( 'WP_TESTS_DOMAIN', 'localhost' );

• Set the environment variable, example: export WP_DEVELOP_DIR="/Users/petenelson/projects/wordpress/wordpress-develop/"
• Clone this repo locally: git clone [email protected]:petenelson/wp-unit-tests.git
• For a database, I recommend Docker so you don't interfere with any existing database servers.
• Switch to the plugin dir and run composer install to install PHPUnit.
• Switch to the /docker directory and run docker-compose up -d to start the MySQL test database.
• Switch back to the main plugin dir and run ./vendor/bin/phpunit to run the unit tests.
• Bonus: run ./vendor/bin/phpunit --coverage-html test-coverage-html to run the unit tests with HTML test coverage in the test-coverage-htmnl directory.

• Visit travis-ci.org and sign in with your GitHub account.
• Add the repository that's holding your plugin, include a valid .travis.yml file, such as the one from this repo.
• git push new code with unit tests
• Profit?

I keep these handy for copy/paste.

$this->assertTrue( condition );
$this->assertFalse( condition );
$this->assertEmpty( actual );
$this->assertEquals( expected, actual );
$this->assertContains( needle, haystack );
$this->assertGreaterThan( expected, actual );
$this->assertCount( expectedCount, haystack );