woocommerce/tests/README.md

WooCommerce Tests

This document discusses unit tests. See the e2e README to learn how to setup testing environment for running e2e tests and run them.

Table of contents

• WooCommerce Tests
  • Table of contents
  • Initial Setup
    • MySQL database
    • Setup instructions
  • Running Tests
    • Running tests in PHP 8
  • Writing Tests
  • Automated Tests
  • Code Coverage

Initial Setup

MySQL database

To run the tests, you need to create a test database. You can:

• Access a database on a server
• Connect to your local database on your machine
• Use a solution like VVV - if you are using VVV you might need to vagrant ssh first
• Run a throwaway database in docker with this one-liner: docker run --rm --name woocommerce_test_db -p 3306:3306 -e MYSQL_ROOT_PASSWORD=woocommerce_test_password -d mysql:5.7.33. ( Use tests/bin/install.sh woocommerce_tests root woocommerce_test_password 0.0.0.0 in next step)

Setup instructions

Once you have database, from the WooCommerce root directory run the following:

1. Install PHPUnit via Composer by running:

   $ composer install
   

2. Install WordPress and the WP Unit Test lib using the install.sh script:

   $ tests/bin/install.sh <db-name> <db-user> <db-password> [db-host]
   

You may need to quote strings with backslashes to prevent them from being processed by the shell or other programs.

Example:

$ tests/bin/install.sh woocommerce_tests root root

#  woocommerce_tests is the database name and root is both the MySQL user and its password.

Important: The <db-name> database will be created if it doesn't exist and all data will be removed during testing.

Running Tests

Change to the plugin root directory and type:

$ vendor/bin/phpunit

The tests will execute and you'll be presented with a summary.

You can run specific tests by providing the path and filename to the test class:

$ vendor/bin/phpunit tests/legacy/unit-tests/importer/product.php

A text code coverage summary can be displayed using the --coverage-text option:

$ vendor/bin/phpunit --coverage-text

Running tests in PHP 8

WooCommerce currently supports PHP versions from 7.0 up to 8.0, and this poses an issue with PHPUnit:

• The latest PHPUnit version that supports PHP 7.0 is 6.5.14
• The latest PHPUnit version that WordPress (and thus WooCommerce) supports is 7.5.20, but that version doesn't work on PHP 8

To workaround this, the testing strategy used by WooCommerce is as follows:

• We normally use PHPUnit 6.5.14
• For PHP 8 we use a custom fork of PHPUnit 7.5.20 with support for PHP 8. WooCommerce's GitHub Actions CI workflow is configured to use this fork instead of the old version 6 when running in PHP 8.

If you want to run the tests locally under PHP 8 you'll need to temporarily modify composer.json to use the custom PHPUnit fork in the same way that the GitHub Actions CI workflow file does. These are the commands that you'll need (run them after a regular composer install):

curl -L https://github.com/woocommerce/phpunit/archive/add-compatibility-with-php8-to-phpunit-7.zip -o /tmp/phpunit-7.5-fork.zip
unzip -d /tmp/phpunit-7.5-fork /tmp/phpunit-7.5-fork.zip
composer bin phpunit config --unset platform
composer bin phpunit config repositories.0 '{"type": "path", "url": "/tmp/phpunit-7.5-fork/phpunit-add-compatibility-with-php8-to-phpunit-7", "options": {"symlink": false}}'
composer bin phpunit require --dev -W phpunit/phpunit:@dev --ignore-platform-reqs    

Just remember that you can't include the modified composer.json in any commit!

Writing Tests

There are three different unit test directories:

• tests/legacy/unit-tests contains tests for code in the includes directory. No new tests should be added here, ever; existing test classes shouldn't get new tests either. Fixing faulty existing tests is allowed.
• tests/php/includes is where all the new tests for code in the includes directory should be written.
• tests/php/src is where all the tests for code in the src directory should be written.

Each test file should correspond to an associated source file and be named accordingly: * For src code: The base namespace for tests is Automattic\WooCommerce\Tests. A class named Automattic\WooCommerce\TheNamespace\TheClass should have a test named Automattic\WooCommerce\Tests\TheNamespace\TheClassTest. * For includes code: * When testing classes: use the same approach as for src except that namespaces are not used. So a WC_Something class in includes/somefolder/class-wc-something.php should have its tests in tests/src/internal/somefolder/class-wc-something-test.php. * When testing functions: use one test file per functions group file, for example wc-formatting-functions-test.php for code in the wc-formatting-functions.php file.

See also the guidelines for writing unit tests for src code and the guidelines for includes code.

General guidelines for all the unit tests:

• Each test method should cover a single method or function with one or more assertions
• A single method or function can have multiple associated test methods if it's a large or complex method
• Use the test coverage HTML report (under tmp/coverage/index.html) to examine which lines your tests are covering and aim for 100% coverage
• For code that cannot be tested (e.g. they require a certain PHP version), you can exclude them from coverage using a comment: // @codeCoverageIgnoreStart and // @codeCoverageIgnoreEnd. For example, see wc_round_tax_total()
• In addition to covering each line of a method/function, make sure to test common input and edge cases.
• Prefer assertSame() where possible as it tests both type and value
• Remember that only methods prefixed with test will be run so use helper methods liberally to keep test methods small and reduce code duplication. If there is a common helper method used in multiple test files, consider adding it to the WC_Unit_Test_Case class so it can be shared by all test cases
• Filters persist between test cases so be sure to remove them in your test method or in the tearDown() method.
• Use data providers where possible. Be sure that their name is like data_provider_function_to_test (i.e. the data provider for test_is_postcode would be data_provider_test_is_postcode). Read more about data providers here.

Automated Tests

Tests are automatically run with GitHub Actions for each commit and pull request.

Code Coverage

Code coverage is available on Codecov which receives updated data after each build.