.. index:: single: PHPUnitBridge single: Components; PHPUnitBridge The PHPUnit Bridge ================== The PHPUnit Bridge provides utilities to report legacy tests and usage of deprecated code and helpers for mocking native functions related to time, DNS and class existence. It comes with the following features: * Forces the tests to use a consistent locale (``C``) (if you create locale-sensitive tests, use PHPUnit's ``setLocale()`` method); * Auto-register ``class_exists`` to load Doctrine annotations (when used); * It displays the whole list of deprecated features used in the application; * Displays the stack trace of a deprecation on-demand; * Provides a ``ClockMock``, ``DnsMock`` and ``ClassExistsMock`` classes for tests sensitive to time, network or class existence; * Provides a modified version of PHPUnit that allows 1. separating the dependencies of your app from those of phpunit to prevent any unwanted constraints to apply; 2. running tests in parallel when a test suite is split in several phpunit.xml files; 3. recording and replaying skipped tests; * It allows to create tests that are compatible with multiple PHPUnit versions (because it provides polyfills for missing methods, namespaced aliases for non-namespaced classes, etc.). Installation ------------ .. code-block:: terminal $ composer require --dev symfony/phpunit-bridge .. include:: /components/require_autoload.rst.inc .. note:: The PHPUnit bridge is designed to work with all maintained versions of Symfony components, even across different major versions of them. You should always use its very latest stable major version to get the most accurate deprecation report. If you plan to :ref:`write-assertions-about-deprecations` and use the regular PHPUnit script (not the modified PHPUnit script provided by Symfony), you have to register a new `test listener`_ called ``SymfonyTestsListener``: .. code-block:: xml Usage ----- .. seealso:: This article explains how to use the PhpUnitBridge features as an independent component in any PHP application. Read the :doc:`/testing` article to learn about how to use it in Symfony applications. Once the component is installed, a ``simple-phpunit`` script is created in the ``vendor/`` directory to run tests. This script wraps the original PHPUnit binary to provide more features: .. code-block:: terminal $ cd my-project/ $ ./vendor/bin/simple-phpunit After running your PHPUnit tests, you will get a report similar to this one: .. code-block:: terminal $ ./vendor/bin/simple-phpunit PHPUnit by Sebastian Bergmann. Configuration read from /phpunit.xml.dist ................. Time: 1.77 seconds, Memory: 5.75Mb OK (17 tests, 21 assertions) Remaining deprecation notices (2) getEntityManager is deprecated since Symfony 2.1. Use getManager instead: 2x 1x in DefaultControllerTest::testPublicUrls from App\Tests\Controller 1x in BlogControllerTest::testIndex from App\Tests\Controller The summary includes: **Unsilenced** Reports deprecation notices that were triggered without the recommended `@-silencing operator`_. **Legacy** Deprecation notices denote tests that explicitly test some legacy features. **Remaining/Other** Deprecation notices are all other (non-legacy) notices, grouped by message, test class and method. .. note:: If you don't want to use the ``simple-phpunit`` script, register the following `PHPUnit event listener`_ in your PHPUnit configuration file to get the same report about deprecations (which is created by a `PHP error handler`_ called :class:`Symfony\\Bridge\\PhpUnit\\DeprecationErrorHandler`): .. code-block:: xml Running Tests in Parallel ------------------------- The modified PHPUnit script allows running tests in parallel by providing a directory containing multiple test suites with their own ``phpunit.xml.dist``. .. code-block:: terminal ├── tests/ │   ├── Functional/ │   │   ├── ... │   │   └── phpunit.xml.dist │   ├── Unit/ │   │   ├── ... │   │   └── phpunit.xml.dist .. code-block:: terminal $ ./vendor/bin/simple-phpunit tests/ The modified PHPUnit script will recursively go through the provided directory, up to a depth of 3 subdirectories or the value specified by the environment variable ``SYMFONY_PHPUNIT_MAX_DEPTH``, looking for ``phpunit.xml.dist`` files and then running each suite it finds in parallel, collecting their output and displaying each test suite's results in their own section. Trigger Deprecation Notices --------------------------- Deprecation notices can be triggered by using ``trigger_deprecation`` from the ``symfony/deprecation-contracts`` package:: // indicates something is deprecated since version 1.3 of vendor-name/packagename trigger_deprecation('vendor-name/package-name', '1.3', 'Your deprecation message'); // you can also use printf format (all arguments after the message will be used) trigger_deprecation('...', '1.3', 'Value "%s" is deprecated, use ... instead.', $value); Mark Tests as Legacy -------------------- There are three ways to mark a test as legacy: * (**Recommended**) Add the ``@group legacy`` annotation to its class or method; * Make its class name start with the ``Legacy`` prefix; * Make its method name start with ``testLegacy*()`` instead of ``test*()``. .. note:: If your data provider calls code that would usually trigger a deprecation, you can prefix its name with ``provideLegacy`` or ``getLegacy`` to silence these deprecations. If your data provider does not execute deprecated code, it is not required to choose a special naming just because the test being fed by the data provider is marked as legacy. Also be aware that choosing one of the two legacy prefixes will not mark tests as legacy that make use of this data provider. You still have to mark them as legacy tests explicitly. Configuration ------------- In case you need to inspect the stack trace of a particular deprecation triggered by your unit tests, you can set the ``SYMFONY_DEPRECATIONS_HELPER`` `environment variable`_ to a regular expression that matches this deprecation's message, enclosed with ``/``. For example, with: .. code-block:: xml `PHPUnit`_ will stop your test suite once a deprecation notice is triggered whose message contains the ``"foobar"`` string. Making Tests Fail ~~~~~~~~~~~~~~~~~ By default, any non-legacy-tagged or any non-`@-silenced <@-silencing operator>`_ deprecation notices will make tests fail. Alternatively, you can configure an arbitrary threshold by setting ``SYMFONY_DEPRECATIONS_HELPER`` to ``max[total]=320`` for instance. It will make the tests fails only if a higher number of deprecation notices is reached (``0`` is the default value). You can have even finer-grained control by using other keys of the ``max`` array, which are ``self``, ``direct``, and ``indirect``. The ``SYMFONY_DEPRECATIONS_HELPER`` environment variable accepts a URL-encoded string, meaning you can combine thresholds and any other configuration setting, like this: ``SYMFONY_DEPRECATIONS_HELPER=max[total]=42&max[self]=0&verbose=0`` Internal deprecations ..................... When you maintain a library, having the test suite fail as soon as a dependency introduces a new deprecation is not desirable, because it shifts the burden of fixing that deprecation to any contributor that happens to submit a pull request shortly after a new vendor release is made with that deprecation. To mitigate this, you can either use tighter requirements, in the hope that dependencies will not introduce deprecations in a patch version, or even commit the ``composer.lock`` file, which would create another class of issues. Libraries will often use ``SYMFONY_DEPRECATIONS_HELPER=max[total]=999999`` because of this. This has the drawback of allowing contributions that introduce deprecations but: * forget to fix the deprecated calls if there are any; * forget to mark appropriate tests with the ``@group legacy`` annotations. By using ``SYMFONY_DEPRECATIONS_HELPER=max[self]=0``, deprecations that are triggered outside the ``vendors`` directory will be accounted for separately, while deprecations triggered from a library inside it will not (unless you reach 999999 of these), giving you the best of both worlds. Direct and Indirect Deprecations ................................ When working on a project, you might be more interested in ``max[direct]``. Let's say you want to fix deprecations as soon as they appear. A problem many developers experience is that some dependencies they have tend to lag behind their own dependencies, meaning they do not fix deprecations as soon as possible, which means you should create a pull request on the outdated vendor, and ignore these deprecations until your pull request is merged. The ``max[direct]`` config allows you to put a threshold on direct deprecations only, allowing you to notice when *your code* is using deprecated APIs, and to keep up with the changes. You can still use ``max[indirect]`` if you want to keep indirect deprecations under a given threshold. Here is a summary that should help you pick the right configuration: +------------------------+-----------------------------------------------------+ | Value | Recommended situation | +========================+=====================================================+ | max[total]=0 | Recommended for actively maintained projects | | | with robust/no dependencies | +------------------------+-----------------------------------------------------+ | max[direct]=0 | Recommended for projects with dependencies | | | that fail to keep up with new deprecations. | +------------------------+-----------------------------------------------------+ | max[self]=0 | Recommended for libraries that use | | | the deprecation system themselves and | | | cannot afford to use one of the modes above. | +------------------------+-----------------------------------------------------+ Disabling the Verbose Output ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ By default, the bridge will display a detailed output with the number of deprecations and where they arise. If this is too much for you, you can use ``SYMFONY_DEPRECATIONS_HELPER=verbose=0`` to turn the verbose output off. Disabling the Deprecation Helper ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Set the ``SYMFONY_DEPRECATIONS_HELPER`` environment variable to ``disabled=1`` to completely disable the deprecation helper. This is useful to make use of the rest of features provided by this component without getting errors or messages related to deprecations. .. _write-assertions-about-deprecations: Deprecation Notices at Autoloading Time ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ By default, the PHPUnit Bridge uses ``DebugClassLoader`` from the :doc:`ErrorHandler component ` to throw deprecation notices at class autoloading time. This can be disabled with the ``debug-class-loader`` option. .. code-block:: xml 0 Write Assertions about Deprecations ----------------------------------- When adding deprecations to your code, you might like writing tests that verify that they are triggered as required. To do so, the bridge provides the ``expectDeprecation()`` method that you can use on your test methods. It requires you to pass the expected message, given in the same format as for the `PHPUnit's assertStringMatchesFormat()`_ method. If you expect more than one deprecation message for a given test method, you can use the method several times (order matters):: use PHPUnit\Framework\TestCase; use Symfony\Bridge\PhpUnit\ExpectDeprecationTrait; class MyTest extends TestCase { use ExpectDeprecationTrait; /** * @group legacy */ public function testDeprecatedCode() { // test some code that triggers the following deprecation: // trigger_deprecation('vendor-name/package-name', '5.1', 'This "Foo" method is deprecated.'); $this->expectDeprecation('Since vendor-name/package-name 5.1: This "%s" method is deprecated'); // ... // test some code that triggers the following deprecation: // trigger_deprecation('vendor-name/package-name', '4.4', 'The second argument of the "Bar" method is deprecated.'); $this->expectDeprecation('Since vendor-name/package-name 4.4: The second argument of the "%s" method is deprecated.'); } } .. deprecated:: 5.1 Symfony versions previous to 5.1 also included a ``@expectedDeprecation`` annotation to test deprecations, but it was deprecated in favor of the method. Display the Full Stack Trace ---------------------------- By default, the PHPUnit Bridge displays only deprecation messages. To show the full stack trace related to a deprecation, set the value of ``SYMFONY_DEPRECATIONS_HELPER`` to a regular expression matching the deprecation message. For example, if the following deprecation notice is thrown: .. code-block:: bash 1x: Doctrine\Common\ClassLoader is deprecated. 1x in EntityTypeTest::setUp from Symfony\Bridge\Doctrine\Tests\Form\Type Running the following command will display the full stack trace: .. code-block:: terminal $ SYMFONY_DEPRECATIONS_HELPER='/Doctrine\\Common\\ClassLoader is deprecated\./' ./vendor/bin/simple-phpunit Testing with Multiple PHPUnit Versions -------------------------------------- When testing a library that has to be compatible with several versions of PHP, the test suite cannot use the latest versions of PHPUnit because: * PHPUnit 8 deprecated several methods in favor of other methods which are not available in older versions (e.g. PHPUnit 4); * PHPUnit 8 added the ``void`` return type to the ``setUp()`` method, which is not compatible with PHP 5.5; * PHPUnit switched to namespaced classes starting from PHPUnit 6, so tests must work with and without namespaces. Polyfills for the Unavailable Methods ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ When using the ``simple-phpunit`` script, PHPUnit Bridge injects polyfills for most methods of the ``TestCase`` and ``Assert`` classes (e.g. ``expectException()``, ``expectExceptionMessage()``, ``assertContainsEquals()``, etc.). This allows writing test cases using the latest best practices while still remaining compatible with older PHPUnit versions. 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 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 :class:`Symfony\\Bridge\\PhpUnit\\SetUpTearDownTrait`, which provides the right signature for the ``setUp()``, ``tearDown()``, ``setUpBeforeClass()`` and ``tearDownAfterClass()`` methods and delegates the call to the ``doSetUp()``, ``doTearDown()``, ``doSetUpBeforeClass()`` and ``doTearDownAfterClass()`` methods:: use PHPUnit\Framework\TestCase; use Symfony\Bridge\PhpUnit\SetUpTearDownTrait; class MyTest extends TestCase { // when using the SetUpTearDownTrait, methods like doSetup() can // be defined with and without the 'void' return type, as you wish use SetUpTearDownTrait; private function doSetup() { // ... } protected function doSetup(): void { // ... } } Using 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. Time-sensitive Tests -------------------- Use Case ~~~~~~~~ If you have this kind of time-related tests:: use PHPUnit\Framework\TestCase; use Symfony\Component\Stopwatch\Stopwatch; class MyTest extends TestCase { public function testSomething() { $stopwatch = new Stopwatch(); $stopwatch->start('event_name'); sleep(10); $duration = $stopwatch->stop('event_name')->getDuration(); $this->assertEquals(10000, $duration); } } You used the :doc:`Symfony Stopwatch Component ` to calculate the duration time of your process, here 10 seconds. However, depending on the load of the server or the processes running on your local machine, the ``$duration`` could for example be ``10.000023s`` instead of ``10s``. This kind of tests are called transient tests: they are failing randomly depending on spurious and external circumstances. They are often cause trouble when using public continuous integration services like `Travis CI`_. Clock Mocking ~~~~~~~~~~~~~ The :class:`Symfony\\Bridge\\PhpUnit\\ClockMock` class provided by this bridge allows you to mock the PHP's built-in time functions ``time()``, ``microtime()``, ``sleep()``, ``usleep()`` and ``gmdate()``. Additionally the function ``date()`` is mocked so it uses the mocked time if no timestamp is specified. Other functions with an optional timestamp parameter that defaults to ``time()`` will still use the system time instead of the mocked time. This means that you may need to change some code in your tests. For example, instead of ``new DateTime()``, you should use ``DateTime::createFromFormat('U', time())`` to use the mocked ``time()`` function. To use the ``ClockMock`` class in your test, add the ``@group time-sensitive`` annotation to its class or methods. This annotation only works when executing PHPUnit using the ``vendor/bin/simple-phpunit`` script or when registering the following listener in your PHPUnit configuration: .. code-block:: xml .. note:: If you don't want to use the ``@group time-sensitive`` annotation, you can register the ``ClockMock`` class manually by calling ``ClockMock::register(__CLASS__)`` and ``ClockMock::withClockMock(true)`` before the test and ``ClockMock::withClockMock(false)`` after the test. As a result, the following is guaranteed to work and is no longer a transient test:: use PHPUnit\Framework\TestCase; use Symfony\Component\Stopwatch\Stopwatch; /** * @group time-sensitive */ class MyTest extends TestCase { public function testSomething() { $stopwatch = new Stopwatch(); $stopwatch->start('event_name'); sleep(10); $duration = $stopwatch->stop('event_name')->getDuration(); $this->assertEquals(10000, $duration); } } And that's all! .. caution:: Time-based function mocking follows the `PHP namespace resolutions rules`_ so "fully qualified function calls" (e.g ``\time()``) cannot be mocked. The ``@group time-sensitive`` annotation is equivalent to calling ``ClockMock::register(MyTest::class)``. If you want to mock a function used in a different class, do it explicitly using ``ClockMock::register(MyClass::class)``:: // the class that uses the time() function to be mocked namespace App; class MyClass { public function getTimeInHours() { return time() / 3600; } } // the test that mocks the external time() function explicitly namespace App\Tests; use App\MyClass; use PHPUnit\Framework\TestCase; use Symfony\Bridge\PhpUnit\ClockMock; /** * @group time-sensitive */ class MyTest extends TestCase { public function testGetTimeInHours() { ClockMock::register(MyClass::class); $my = new MyClass(); $result = $my->getTimeInHours(); $this->assertEquals(time() / 3600, $result); } } .. tip:: An added bonus of using the ``ClockMock`` class is that time passes instantly. Using PHP's ``sleep(10)`` will make your test wait for 10 actual seconds (more or less). In contrast, the ``ClockMock`` class advances the internal clock the given number of seconds without actually waiting that time, so your test will execute 10 seconds faster. DNS-sensitive Tests ------------------- Tests that make network connections, for example to check the validity of a DNS record, can be slow to execute and unreliable due to the conditions of the network. For that reason, this component also provides mocks for these PHP functions: * :phpfunction:`checkdnsrr` * :phpfunction:`dns_check_record` * :phpfunction:`getmxrr` * :phpfunction:`dns_get_mx` * :phpfunction:`gethostbyaddr` * :phpfunction:`gethostbyname` * :phpfunction:`gethostbynamel` * :phpfunction:`dns_get_record` Use Case ~~~~~~~~ Consider the following example that tests a custom class called ``DomainValidator`` which defines a ``checkDnsRecord`` option to also validate that a domain is associated to a valid host:: use App\Validator\DomainValidator; use PHPUnit\Framework\TestCase; class MyTest extends TestCase { public function testEmail() { $validator = new DomainValidator(['checkDnsRecord' => true]); $isValid = $validator->validate('example.com'); // ... } } In order to avoid making a real network connection, add the ``@dns-sensitive`` annotation to the class and use the ``DnsMock::withMockedHosts()`` to configure the data you expect to get for the given hosts:: use App\Validator\DomainValidator; use PHPUnit\Framework\TestCase; use Symfony\Bridge\PhpUnit\DnsMock; /** * @group dns-sensitive */ class DomainValidatorTest extends TestCase { public function testEmails() { DnsMock::withMockedHosts([ 'example.com' => [['type' => 'A', 'ip' => '1.2.3.4']], ]); $validator = new DomainValidator(['checkDnsRecord' => true]); $isValid = $validator->validate('example.com'); // ... } } The ``withMockedHosts()`` method configuration is defined as an array. The keys are the mocked hosts and the values are arrays of DNS records in the same format returned by :phpfunction:`dns_get_record`, so you can simulate diverse network conditions:: DnsMock::withMockedHosts([ 'example.com' => [ [ 'type' => 'A', 'ip' => '1.2.3.4', ], [ 'type' => 'AAAA', 'ipv6' => '::12', ], ], ]); Class Existence Based Tests --------------------------- Tests that behave differently depending on existing classes, for example Composer's development dependencies, are often hard to test for the alternate case. For that reason, this component also provides mocks for these PHP functions: * :phpfunction:`class_exists` * :phpfunction:`interface_exists` * :phpfunction:`trait_exists` Use Case ~~~~~~~~ Consider the following example that relies on the ``Vendor\DependencyClass`` to toggle a behavior:: use Vendor\DependencyClass; class MyClass { public function hello(): string { if (class_exists(DependencyClass::class)) { return 'The dependency behavior.'; } return 'The default behavior.'; } } A regular test case for ``MyClass`` (assuming the development dependencies are installed during tests) would look like:: use MyClass; use PHPUnit\Framework\TestCase; class MyClassTest extends TestCase { public function testHello() { $class = new MyClass(); $result = $class->hello(); // "The dependency behavior." // ... } } In order to test the default behavior instead use the ``ClassExistsMock::withMockedClasses()`` to configure the expected classes, interfaces and/or traits for the code to run:: use MyClass; use PHPUnit\Framework\TestCase; use Vendor\DependencyClass; class MyClassTest extends TestCase { // ... public function testHelloDefault() { ClassExistsMock::register(MyClass::class); ClassExistsMock::withMockedClasses([DependencyClass::class => false]); $class = new MyClass(); $result = $class->hello(); // "The default behavior." // ... } } Troubleshooting --------------- The ``@group time-sensitive`` and ``@group dns-sensitive`` annotations work "by convention" and assume that the namespace of the tested class can be obtained just by removing the ``Tests\`` part from the test namespace. I.e. if your test cases fully-qualified class name (FQCN) is ``App\Tests\Watch\DummyWatchTest``, it assumes the tested class namespace is ``App\Watch``. If this convention doesn't work for your application, configure the mocked namespaces in the ``phpunit.xml`` file, as done for example in the :doc:`HttpKernel Component `: .. code-block:: xml Symfony\Component\HttpFoundation Under the hood, a PHPUnit listener injects the mocked functions in the tested classes' namespace. In order to work as expected, the listener has to run before the tested class ever runs. By default, the mocked functions are created when the annotation are found and the corresponding tests are run. Depending on how your tests are constructed, this might be too late. In this case, you will need to declare the namespaces of the tested classes in your ``phpunit.xml.dist``. .. code-block:: xml Acme\MyClassTest Modified PHPUnit script ----------------------- This bridge provides a modified version of PHPUnit that you can call by using its ``bin/simple-phpunit`` command. It has the following features: * Works with a standalone vendor directory that doesn't conflict with yours; * Does not embed ``prophecy`` to prevent any conflicts with its dependencies; * Uses PHPUnit 4.8 when run with PHP <=5.5, PHPUnit 5.7 when run with PHP >=5.6 and PHPUnit 6.5 when run with PHP >=7.2; * Collects and replays skipped tests when the ``SYMFONY_PHPUNIT_SKIPPED_TESTS`` env var is defined: the env var should specify a file name that will be used for storing skipped tests on a first run, and replay them on the second run; * Parallelizes test suites execution when given a directory as argument, scanning this directory for ``phpunit.xml.dist`` files up to ``SYMFONY_PHPUNIT_MAX_DEPTH`` levels (specified as an env var, defaults to ``3``); The script writes the modified PHPUnit it builds in a directory that can be configured by the ``SYMFONY_PHPUNIT_DIR`` env var, or in the same directory as the ``simple-phpunit`` if it is not provided. It's also possible to set this env var in the ``phpunit.xml.dist`` file. By default, these are the PHPUnit versions used depending on the installed PHP versions: ===================== =============================== Installed PHP version PHPUnit version used by default ===================== =============================== PHP <= 5.5 PHPUnit 4.8 PHP 5.6 PHPUnit 5.7 PHP 7.0 PHPUnit 6.5 PHP 7.1 PHPUnit 7.5 PHP >= 7.2 PHPUnit 8.3 ===================== =============================== If you have installed the bridge through Composer, you can run it by calling e.g.: .. code-block:: terminal $ vendor/bin/simple-phpunit .. tip:: It's possible to change the base version of PHPUnit by setting the ``SYMFONY_PHPUNIT_VERSION`` env var in the ``phpunit.xml.dist`` file (e.g. ````). This is the preferred method as it can be committed to your version control repository. It's also possible to set ``SYMFONY_PHPUNIT_VERSION`` as a real env var (not defined in a :ref:`dotenv file `). .. tip:: If you still need to use ``prophecy`` (but not ``symfony/yaml``), then set the ``SYMFONY_PHPUNIT_REMOVE`` env var to ``symfony/yaml``. It's also possible to set this env var in the ``phpunit.xml.dist`` file. Code Coverage Listener ---------------------- By default, the code coverage is computed with the following rule: if a line of code is executed, then it is marked as covered. The test which executes a line of code is therefore marked as "covering the line of code". This can be misleading. Consider the following example:: class Bar { public function barMethod() { return 'bar'; } } class Foo { private $bar; public function __construct(Bar $bar) { $this->bar = $bar; } public function fooMethod() { $this->bar->barMethod(); return 'bar'; } } class FooTest extends PHPUnit\Framework\TestCase { public function test() { $bar = new Bar(); $foo = new Foo($bar); $this->assertSame('bar', $foo->fooMethod()); } } The ``FooTest::test`` method executes every single line of code of both ``Foo`` and ``Bar`` classes, but ``Bar`` is not truly tested. The ``CoverageListener`` aims to fix this behavior by adding the appropriate `@covers`_ annotation on each test class. If a test class already defines the ``@covers`` annotation, this listener does nothing. Otherwise, it tries to find the code related to the test by removing the ``Test`` part of the classname: ``My\Namespace\Tests\FooTest`` -> ``My\Namespace\Foo``. Installation ~~~~~~~~~~~~ Add the following configuration to the ``phpunit.xml.dist`` file: .. code-block:: xml If the logic used to find the related code is too simple or doesn't work for your application, you can use your own SUT (System Under Test) solver: .. code-block:: xml My\Namespace\SutSolver::solve The ``My\Namespace\SutSolver::solve`` can be any PHP callable and receives the current test as its first argument. Finally, the listener can also display warning messages when the SUT solver does not find the SUT: .. code-block:: xml true .. _`PHPUnit`: https://phpunit.de .. _`PHPUnit event listener`: https://phpunit.de/manual/current/en/extending-phpunit.html#extending-phpunit.PHPUnit_Framework_TestListener .. _`PHPUnit's assertStringMatchesFormat()`: https://phpunit.de/manual/current/en/appendixes.assertions.html#appendixes.assertions.assertStringMatchesFormat .. _`PHP error handler`: https://www.php.net/manual/en/book.errorfunc.php .. _`environment variable`: https://phpunit.de/manual/current/en/appendixes.configuration.html#appendixes.configuration.php-ini-constants-variables .. _`@-silencing operator`: https://www.php.net/manual/en/language.operators.errorcontrol.php .. _`Travis CI`: https://travis-ci.org/ .. _`test listener`: https://phpunit.de/manual/current/en/appendixes.configuration.html#appendixes.configuration.test-listeners .. _`@covers`: https://phpunit.de/manual/current/en/appendixes.annotations.html#appendixes.annotations.covers .. _`PHP namespace resolutions rules`: https://www.php.net/manual/en/language.namespaces.rules.php