yoast/wp-test-utils

PHPUnit cross-version compatibility layer for testing plugins and themes build for WordPress

1.1.1 2022-11-17 14:06 UTC

README

Version CS Build Status Test Build Status Minimum PHP Version License: BSD3

This library contains a set of utilities for running automated tests for WordPress plugins and themes.

Requirements

  • PHP 5.6 or higher.

The following packages will be automatically required via Composer:

Installation

To install this package, run:

composer require --dev yoast/wp-test-utils

To update this package, run:

composer update --dev yoast/wp-test-utils --with-dependencies

Features

This library contains a set of utilities for running automated tests for WordPress plugins and themes.

Utilities for running tests using BrainMonkey

Basic TestCase for use with BrainMonkey

Features of this TestCase:

  1. Cross-version compatibility with PHPUnit 5.7 - 9.x via the PHPUnit Polyfills package.
  2. The BrainMonkey and Mockery set up and tear down is already handled.
  3. Tests using Mockery expectations will not be marked as "risky", even when there are no assertions.
  4. Makes alternative implementations of the BrainMonkey native stubTranslationFunctions() and stubEscapeFunctions() functions available.
    The BrainMonkey native functions create stubs which will apply basic HTML escaping if the stubbed function is an escaping function, like esc_html__().
    The alternative implementations of these functions will create stubs which will return the original value without change. This makes creating tests easier as the $expected value does not need to account for the HTML escaping.
    Note: the alternative implementation should be used selectively.
  5. Helper functions for setting expectations for generated output.
  6. Helper functions for creating "dummy" test doubles for unavailable classes.

Implementation example:

<?php
namespace PackageName\Tests;

use Yoast\WPTestUtils\BrainMonkey\TestCase;

class FooTest extends TestCase {
    protected function set_up() {
        parent::set_up();
        // Your own additional setup.
    }

    protected function tear_down() {
        // Your own additional tear down.
        parent::tear_down();
    }

    public function testAFunctionContainingStringTranslating() {
        $this->stubTranslationFunctions(); // No HTML escaping will be applied.
        // Or:
        \Brain\Monkey\Functions\stubTranslationFunctions(); // HTML escaping will be applied.

        // Test your code.
    }

    public function testAFunctionContainingOutputEscaping() {
        $this->stubEscapeFunctions(); // No HTML escaping will be applied.
        // Or:
        \Brain\Monkey\Functions\stubEscapeFunctions(); // HTML escaping will be applied.

        // Test your code.
    }
}

Yoast TestCase for use with BrainMonkey

Features of this TestCase:

  1. All the benefits of the basic TestCase as outlined above.

  2. By default, the following WordPress functions will be stubbed, in addition to the stubs already provided by BrainMonkey:

    WP function Stub will return
    get_bloginfo( 'charset' ) 'UTF-8'
    get_bloginfo( 'language' ) 'English'
    is_multisite() Value of the WP_TESTS_MULTISITE PHP constant as a boolean (if defined), otherwise false
    mysql2date( $format, $date ) $date (original value)
    number_format_i18n( $number, $decimals ) $number (original value)
    sanitize_text_field( $str ) $str (original value)
    site_url() 'https://www.example.org'
    wp_kses_post( $data ) $data (original value)
    wp_parse_args( $args, $defaults ) array_merge( $defaults, $args )
    wp_strip_all_tags( $string, $remove_breaks = false ) Emulated return value as per the WP native functionality, might miss some edge cases
    wp_slash( $value ) $value (original value)
    wp_unslash( $value ) stripslashes( $value ) if $value is a string, otherwise $value (original value)

Implementation example:

<?php
namespace PackageName\Tests;

use Yoast\WPTestUtils\BrainMonkey\YoastTestCase;

class FooTest extends YoastTestCase {
    // Your test code.
}

Bootstrap file for use with BrainMonkey

Most of the time, using the Composer vendor/autoload.php file as your bootstrap file for PHPUnit will be sufficient.

However, in the context of testing WordPress plugins and themes, it can be useful to have access to certain constants which WordPress natively declares.

The bootstrap file for use with BrainMonkey will make sure that the following constants are defined:

ABSPATH MINUTE_IN_SECONDS HOUR_IN_SECONDS DAY_IN_SECONDS
WEEK_IN_SECONDS MONTH_IN_SECONDS YEAR_IN_SECONDS
DB_HOST DB_NAME DB_USER DB_PASSWORD

In addition to that, it will clear the PHP Opcache before running the tests.

Implementation example:

<?php
// File: tests/bootstrap.php
require_once dirname( __DIR__ ) . '/vendor/yoast/wp-test-utils/src/BrainMonkey/bootstrap.php';
require_once dirname( __DIR__ ) . '/vendor/autoload.php';

To tell PHPUnit to use this bootstrap file, use --bootstrap tests/bootstrap.php on the command-line or add the bootstrap="tests/bootstrap.php" attribute to your phpunit.xml.dist file.

Helpers to create test doubles for unavailable classes

Why you may need to create test doubles for unavailable classes

Typically a mock for an unavailable class is created using Mockery::mock() or Mockery::mock( 'Unavailable' ).

When either the test or the code under test sets a property on such a mock, this will lead to a "Creation of dynamic properties is deprecated" notice on PHP >= 8.2, which can cause tests to error out.

If you know for sure the property being set on the mock is a declared property or a property supported via magic methods on the class which is being mocked, the code under test will under normal circumstances never lead to this deprecation notice, but your tests now do.

Primarly this is an issue with Mockery. A question on how to handle this/to add support for this in Mockery itself is open, but in the mean time a work-around is needed (if you're interested, have a read through the Mockery issue for details about alternative solutions and why those don't work as intended).

How to use the functionality

WP Test Utils offers three new utilities to solve this (as of version 1.1.0).

  • Yoast\WPTestUtils\BrainMonkey\makeDoublesForUnavailableClasses( array $class_names ) for use from within a test bootstrap file.
  • Yoast\WPTestUtils\BrainMonkey\TestCase::makeDoublesForUnavailableClasses( array $class_names ) and Yoast\WPTestUtils\BrainMonkey\TestCase::makeDoubleForUnavailableClass( string $class_name ) for use from within a test class.

These methods can be used to create one or more "fake" test double classes on the fly, which allow for setting (dynamic) properties. These "fake" test double classes are effectively opaque classes which extend stdClass.

These methods are solely intended for classes which are unavailable during the test run and have no effect (at all!) on classes which are available during the test run.

For setting expectations on the "fake" test double, use Mockery::mock( 'FakedClass' ).

Implementation example using the bootstrap function:

You can create the "fake" test doubles for a complete test suite in one go in your test bootstrap file like so:

<?php
// File: tests/bootstrap.php
require_once dirname( __DIR__ ) . '/vendor/yoast/wp-test-utils/src/BrainMonkey/bootstrap.php';
require_once dirname( __DIR__ ) . '/vendor/autoload.php';

Yoast\WPTestUtils\BrainMonkey\makeDoublesForUnavailableClasses( [ 'WP_Post', 'wpdb' ] );

Implementation example using these functions from within a test class:

Alternatively, you can create the "fake" test double(s) last minute in each test class which needs them.

<?php
namespace PackageName\Tests;

use Mockery;
use WP_Post;
use wpdb;
use Yoast\WPTestUtils\BrainMonkey\TestCase;

class FooTest extends TestCase {
    protected function set_up_before_class() {
        parent::set_up_before_class();
        self::makeDoublesForUnavailableClasses( [ WP_Post::class, wpdb::class ] );
        // or if only one class is needed:
        self::makeDoubleForUnavailableClass( WP_Post::class );
    }

    public function testSomethingWhichUsesWpPost() {
        $wp_post = Mockery::mock( WP_Post::class );
        $wp_post->post_title = 'my test title';
        $wp_post->post_type  = 'my_custom_type';

        $this->assertSame( 'expected', \function_under_test( $wp_post ) );
    }
}

Utilities for running integration tests with WordPress

What these utilities solve

  1. Running tests using the PHPUnit native mocking functionality against PHP 8.0, while testing against WordPress 5.6 - 5.8.

    WP 5.6 is the first WordPress version with (beta) support for PHP 8.0.

    In most cases, for WordPress integration tests, the WordPress Core native test bootstrap file will be loaded to set up the test environment, including the database.
    However, WordPress, until WP 5.9, had a hard limit on PHPUnit 7.5 max, while PHPUnit 9.3 is the first PHPUnit version which has full PHP 8.0 support, making testing on PHP 8.0 with WP 5.6 - 5.8 problematic.

    In WordPress 5.6 to 5.8, this problem was solved by adding copies of select PHPUnit 9.x files to the WordPress test suite and loading those files when running PHPUnit 7.x on PHP 8.0, instead of the PHPUnit 7.x native ones.
    The way this solution was implemented, however, is not portable to plugins/themes.

    WP Test Utils solves this problem for plugin and theme integration tests via the WP Integration test bootstrap utilities.

  2. WP 5.9 makes significant changes to the WP Core test suite

    As of WP 5.9, the PHPUnit Polyfills package has become a requirement, test fixtures now need to be declared in snake_case etc.
    For full details about what has changed in the WP Core test suite in WP 5.9, please see the Make Core dev-note about these changes.

    These WP Core test changes have been partially backported and once a plugin/theme integration test suite has been upgraded for the WP 5.9 changes, it can be safely run against the WP trunk and 5.x (5.2 - 5.8) branches.

    There is a caveat to this however:

    • Plugins/themes which test against older WP versions (< 5.2) don't have access to either the polyfills or the snake_case fixture method wrappers.
    • Same goes for tests being run against WP latest until WordPress 5.8.2 has been tagged.
    • Same goes for tests being run against specific WP 5.2 - 5.8 minors released before the backports were committed, i.e. WP 5.2.0 - 5.2.12, WP 5.3.0 - 5.3.9, WP 5.4.0 - 5.4.7, WP 5.5.0 - 5.5.6, WP 5.6.0 - 5.6.5, WP 5.7.0 - 5.7.3 and WP 5.8.0 - 5.8.1.

    WP Test Utils solves this problem by having two version of the TestCase offered and loading the correct one depending on the WP version the tests are being run against.
    The loading of the correct TestCase is, again, handled via the WP Integration test bootstrap utilities.

Basic TestCase for WordPress integration tests

Features of this TestCase:

  1. Extends the WP native base test case WP_UnitTestCase, making all the WP Core test utilities available to your integration test classes.
  2. Cross-version compatibility with PHPUnit 5.7 - 9.x via the PHPUnit Polyfills package.
    Using these polyfills you can use the up-to-date PHPUnit 9.x syntax, independently of the WP version against which the tests are being run.
    Note: WordPress Core in WP < 5.9 still limits integration tests to running on PHPUnit 7.5 max. As of WP 5.9, tests can run cross-version on PHPUnit 5.7 - 9.x.
  3. Ability to use the fixture method snake_case wrappers independently of the WP version against which the tests are being run.
  4. Helper functions for setting expectations for generated output.

Implementation example:

<?php
namespace PackageName\Tests;

use Yoast\WPTestUtils\WPIntegration\TestCase;

class FooTest extends TestCase {
    protected function set_up() {
        parent::set_up();
        // Your own additional setup.
    }
}

Bootstrap utility functions and custom autoloader

The WP Integration bootstrap utilities consist of:

  • A bootstrap-functions.php file with utility functions for use in the test bootstrap file for the integration tests for a plugin or theme.
  • A custom autoloader which will selectively autoload the WP copies of the PHPUnit 9 native MockBuilder files for PHPUnit < 9 when run on PHP 8 and which will handle loading the correct TestCase version depending on the WP version tests are run against.

The bootstrap utilies presume two things:

  1. This package is installed as a dependency of a plugin via Composer and will be in the vendor/yoast/wp-test-utils/ directory.
  2. The includes subdirectory of the WordPress Core native tests/phpunit directory is available.

The location of the includes directory containing the test framework files from WordPress Core will be determined in the following manner:

  1. Check if a WP_TESTS_DIR environment variable is available pointing to the WordPress Core ./tests/phpunit directory; or a directory containing a copy of the includes subdirectory from the WordPress Core ./tests/phpunit directory.
  2. If not, check to see if a WP_DEVELOP_DIR environment variable is available which points to a path containing the WordPress Core root directory from a git/svn check-out.
  3. If not, it is checked if the plugin/theme is installed within WordPress itself in a src/wp-content/plugins/plugin-name or src/wp-content/themes/theme-name directory, with this package in the src/wp-content/plugins/plugin-name/vendor/yoast/wp-test-utils directory.
  4. As a last resort, a check is done for the typical WP-CLI scaffold command setup, where the includes subdirectory from the WordPress Core tests/phpunit directory has been placed in the system temp directory.

These checks are in line with typical integration test setups in the context of WordPress.

👉 The above mentioned environment variables can be set on the OS level or from within a phpunit.xml[.dist] file.

Using the bootstrap utilities

There are two prevelant patterns for wiring in a plugin/theme to WordPress in an integration test bootstrap file. The bootstrap utilities can be used with both.

To implement use of the bootstrap utilities, use whichever pattern matches your current bootstrap file most closely.

Implementation example 1:

use Yoast\WPTestUtils\WPIntegration;

if ( getenv( 'WP_PLUGIN_DIR' ) !== false ) {
    define( 'WP_PLUGIN_DIR', getenv( 'WP_PLUGIN_DIR' ) );
}

$GLOBALS['wp_tests_options'] = [
    'active_plugins' => [ 'plugin-name/main-file.php' ],
];

require_once dirname( __DIR__ ) . '/vendor/yoast/wp-test-utils/src/WPIntegration/bootstrap-functions.php';

/*
 * Bootstrap WordPress. This will also load the Composer autoload file, the PHPUnit Polyfills
 * and the custom autoloader for the TestCase and the mock object classes.
 */
WPIntegration\bootstrap_it();

if ( ! defined( 'WP_PLUGIN_DIR' ) || file_exists( WP_PLUGIN_DIR . '/plugin-name/main-file.php' ) === false ) {
    echo PHP_EOL, 'ERROR: Please check whether the WP_PLUGIN_DIR environment variable is set and set to the correct value. The integration test suite won\'t be able to run without it.', PHP_EOL;
    exit( 1 );
}

Implementation example 2:

use Yoast\WPTestUtils\WPIntegration;

require_once dirname( __DIR__ ) . '/vendor/yoast/wp-test-utils/src/WPIntegration/bootstrap-functions.php';

$_tests_dir = WPIntegration\get_path_to_wp_test_dir();

// Get access to tests_add_filter() function.
require_once $_tests_dir . 'includes/functions.php';

/**
 * Callback to manually load the plugin
 */
function _manually_load_plugin() {
    require_once __DIR__ . '/relative/path/to/main-file.php';
}

// Add plugin to active mu-plugins to make sure it gets loaded.
tests_add_filter( 'muplugins_loaded', '_manually_load_plugin' );

/*
 * Bootstrap WordPress. This will also load the Composer autoload file, the PHPUnit Polyfills
 * and the custom autoloader for the TestCase and the mock object classes.
 */
WPIntegration\bootstrap_it();

Test Helpers

Yoast\WPTestUtils\Helpers\EscapeOutputHelper trait

PHPUnit natively contains the expectOutputString() (exact string) and the expectOutputRegex() (regex match) method, but sometimes you need a little more flexibility.

A typical pattern used, is to check whether the output generated contains certain substrings. And a typical reason for mismatched output versus expectation, is a mismatch in line endings.

This EscapeOutputHelper trait adds the following functions to solve these issues:

  • expectOutputContains( $expected, $ignoreEolDiff = true ) to verify whether generated output contains a certain substring. In the same vein as the PHPUnit native methods, only one such expectation can be set in a test. If a test needs to check that the generated output contains multiple different substrings, refactor the test to use a data provider feeding the test one substring at a time.
  • normalizeLineEndings( $output ) which is intended to be used in conjunction with the PHPUnit native setOutputCallback() method to normalize line endings in the actual output before comparing output expectations with the actual output.

👉 This trait is automatically available to test classes based on the BrainMonkey or WPIntegration TestCases as included in WP Test Utils.

Contributing

Contributions to this project are welcome. Clone the repo, branch off from develop, make your changes, commit them and send in a pull request.

If you are unsure whether the changes you are proposing would be welcome, please open an issue first to discuss your proposal.

License

This code is released under the BSD-3-Clause License.