WordPress Plugin Unit Test with BrainMonkey and PHPUnit

composer require --dev brain/monkey phpunit

<?php
/**
 * The following snippets uses `PLUGIN` to prefix
 * the constants and class names. You should replace
 * it with something that matches your plugin name.
 */
// define test environment
define( 'PLUGIN_PHPUNIT', true );

// define fake ABSPATH
if ( ! defined( 'ABSPATH' ) ) {
	define( 'ABSPATH', sys_get_temp_dir() );
}
// define fake PLUGIN_ABSPATH
if ( ! defined( 'PLUGIN_ABSPATH' ) ) {
	define( 'PLUGIN_ABSPATH', sys_get_temp_dir() . '/wp-content/plugins/my-plugin/' );
}

require_once __DIR__ . '/../../vendor/autoload.php';

// Include the class for PluginTestCase
require_once __DIR__ . '/inc/PluginTestCase.php';

// Since our plugin files are loaded with composer, we should be good to go

if ( ! defined( 'ABSPATH' ) ) {
	die( '' );
}

<?php
use PHPUnit\Framework\TestCase;
use Mockery\Adapter\Phpunit\MockeryPHPUnitIntegration;
use Brain\Monkey;

/**
 * An abstraction over WP_Mock to do things fast
 * It also uses the snapshot trait
 */
class PluginTestCase extends \PHPUnit\Framework\TestCase {
	use MatchesSnapshots;
	use MockeryPHPUnitIntegration;

	/**
	 * Setup which calls \WP_Mock setup
	 *
	 * @return void
	 */
	public function setUp() {
		parent::setUp();
		Monkey\setUp();
		// A few common passthrough
		// 1. WordPress i18n functions
		Monkey\Functions\when( '__' )
			->returnArg( 1 );
		Monkey\Functions\when( '_e' )
			->returnArg( 1 );
		Monkey\Functions\when( '_n' )
			->returnArg( 1 );
	}

	/**
	 * Teardown which calls \WP_Mock tearDown
	 *
	 * @return void
	 */
	public function tearDown() {
		Monkey\tearDown();
		parent::tearDown();
	}
}

<?xml version="1.0" encoding="UTF-8"?>
<phpunit
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/7.2/phpunit.xsd"
	bootstrap="tests/phpunit/bootstrap.php"
	backupGlobals="true"
	colors="true"
	convertErrorsToExceptions="true"
	convertNoticesToExceptions="true"
	convertWarningsToExceptions="true"
	verbose="true"
	printerClass="PHPUnit\TextUI\ResultPrinter"
	>
	<testsuites>
		<testsuite name="EForm Test Suit">
			<directory suffix="Test.php">./tests/phpunit</directory>
		</testsuite>
	</testsuites>
	<filter>
		<whitelist processUncoveredFilesFromWhitelist="false">
			<directory suffix=".php">./inc</directory>
		</whitelist>
	</filter>
	<logging>
		<log type="coverage-text" target="php://stdout" showUncoveredFiles="true"/>
		<log type="coverage-clover" target="coverage/phpunit/clover.xml" showUncoveredFiles="true"/>
	</logging>
</phpunit>

namespace PluginTest\Stuff;
use \Plugin\Stuff\SomeClass;
use \Brain\Monkey\Functions;

class SomeClassTest extends \PluginTestCase {
	public function test_construct() {
		// arrange
		$_SERVER['REQUEST_METHOD'] = 'POST';
		$_POST = [ 'foo' => '\\\'asas' ];
		// We expect wp_unslash to be called during bootstrap
		Functions\expect( 'wp_unslash' )
			->once()
			->with( $_POST )
			->andReturnFirstArg();
		// We expect plugins_url to be called
		Functions\expect( 'plugins_url' )
			->once()
			->with( '/dist/', PLUGIN_ABSPATH )
			->andReturn( 'https://eform.test/foo/dist/' );
		// Fire
		$stub = $this->getMockForAbstractClass( SomeClass::class );
		$stub_class = get_class( $stub );
		// $base = new \EFormStub\StubAdminBase();
		// We expect admin_menu action to have been added when calling register
		$this->assertTrue( has_action( 'admin_menu', "{$stub_class}->admin_menu()" ) );
		// Assert
		$this->assertEquals( $_POST, $stub->get_post() );
	}
}

vendor/bin/phpunit

{
	"scripts": {
		"test": "phpunit"
	}
}

composer run-script test

use Brain\Monkey\Functions;

class SomeTest extends \PluginTestCase {
	public function test_something() {
		// Our code calls `wp_roles` so we mock it
		$wp_roles = \Mockery::mock( '\WP_Roles' );
		$wp_roles->shouldReceive( 'add_cap' )
			->times( 5 );
		Functions\expect( 'wp_roles' )
			->once()
			->withNoArgs()
			->andReturn( $wp_roles );
		// Act
		// Assume `create_cap` calls `wp_roles` in some way.
		// Then it calls `add_cap` 5 times.
		( new Some() )->create_cap();
	}
}

use Brain\Monkey\Functions;

class SomeTest extends \PluginTestCase {
	public function test_something() {
		// A simple mock for `plugins_url` to return a sample URL
		Functions\when( 'plugins_url' )
			->justReturn( 'https://plugin.com/wp-content/plugins/my-plugin/assets/thing.js' );
		// We expect our method to call `wp_enqueue_script` with specific handler and URL
		// returned by `plugins_url`.
		Functions\expect( 'wp_enqueue_script' )
			->once()
			->with( 'plugin-main-js', \Mockery::type( 'string' ), \Mockery::type( 'array' ), \Mockery::type( 'bool' ) )
			->andReturn( true );
		// act
		( new Some() )->enqueue();
	}
}

use Brain\Monkey\Functions;

class SomeTest extends \PluginTestCase {
	public function test_something() {
		Functions\when( '__' )
			->returnArg( 1 );
		Functions\when( '_e' )
			->returnArg( 1 );
		Functions\when( '_n' )
			->returnArg( 1 );
	}
}

use Brain\Monkey\Functions;

class SomeTest extends \PluginTestCase {
	public function test_something() {
		// Mock add_option
		Functions\when( 'add_option' )->justReturn( true );
		// Mock update_option
		Functions\when( 'update_option' )->justReturn( true );
		// Mock get_option
		Functions\when( 'get_option' )->justReturn( true );
		// Mock delete_option
		Functions\when( 'delete_option' )->justReturn( true );
	}
}

use Brain\Monkey\Functions;

class SomeTest extends \PluginTestCase {
	public function test_something() {
		// Expect get_option to have been called with something
		Functions\expect( 'get_option' )
			->once() // called once
			->with( 'plugin-settings', [] ) // with specified arguments, like get_option( 'plugin-settings', [] );
			->andReturn( [] ); // what it should return?
	}
}