The PHPUnit Bridge component improves the original PHPUnit library with utilities to report usage of deprecated code and helpers for mocking native functions related to time, DNS and class existence.
When testing some code that has to be compatible with several versions of PHP, it's difficult to pick a PHPUnit version: latest versions like PHPUnit 8 use features incompatible with PHP 5.5 and remove methods available in earlier PHPUnit versions. In addition, PHPUnit 6 switched to namespaced classes, so tests must work with and without namespaces.
That's why in Symfony 4.4, we've improved the PHPUnit Bridge with several polyfills that allow to create tests that are compatible with multiple PHPUnit versions.
Polyfills for the Unavailable Methods
When using the simple-phpunit script provided by PHPUnit Bridge instead of
the phpunit script provided by PHPUnit, Symfony injects polyfills for most
of the newest methods of TestCase and Assert classes.
In other words, you can start using new methods in test suites that aren't compatible
with newest versions of PHPUnit, such as expectException(), assertStringContainsString(), etc.
Removing the Void Return Type
When running the simple-phpunit script with the
SYMFONY_PHPUNIT_REMOVE_RETURN_TYPEHINT environment variable set to 1,
the PHPUnit bridge will alter the code of PHPUnit to remove the void return
type (introduced in PHPUnit 8) from setUp(), tearDown(),
setUpBeforeClass() and tearDownAfterClass() methods. This allows you to
write a test compatible with both PHP 5 and PHPUnit 8.
Alternatively, you can use the trait SetUpTearDownTrait in your test class to
inject the methods without the void return type.
Namespaced PHPUnit Classes
The PHPUnit bridge adds namespaced class aliases for most of the PHPUnit classes
declared without namespaces (e.g. PHPUnit_Framework_Assert), allowing you to
always use the namespaced class declaration even when the test is executed with
PHPUnit 4, where namespaces aren't used.
TL;DR If you don't get what this is about, no worries: it's critically required to run the tests of #Symfony on #PHP 7.4 and 5.5 (for branch 3.4). Many don't have these requirements. Yet, if you do, enjoy, the tooling is OSS too!
Yummy! I just spent some time refactoring a couple of test suites in order to make them compatible all the way from phpunit 5.7 to 7.5, and was not enthralled at the idea of having to hammer out of them compatibility with phpunit 8 too. Will the new PhpUnutBridge version be usable in conjunction with Symfony 2.4/php 5.6 ?