The PHPUnit Bridge

The PHPUnit Bridge

The PHPUnit Bridge provides utilities to report legacy tests and usage of deprecated code and a helper for time-sensitive tests.

It comes with the following features:

  • Forces the tests to use a consistent locale (C);
  • 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 and DnsMock helper classes for time or network-sensitive tests.
  • Provides a modified version of PHPUnit that does not embed symfony/yaml nor prophecy to prevent any conflicts with these dependencies.

Installation

You can install the component in 2 different ways:

Then, require the vendor/autoload.php file to enable the autoloading mechanism provided by Composer. Otherwise, your application won't be able to find the classes of this Symfony component.

If you plan to 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:

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<!-- http://phpunit.de/manual/6.0/en/appendixes.configuration.html -->
<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:noNamespaceSchemaLocation="http://schema.phpunit.de/6.0/phpunit.xsd"
>

    <!-- ... -->

    <listeners>
        <listener class="Symfony\Bridge\PhpUnit\SymfonyTestsListener" />
    </listeners>
</phpunit>

Usage

Once the component is installed, it automatically registers a PHPUnit event listener which in turn registers a PHP error handler called DeprecationErrorHandler. After running your PHPUnit tests, you will get a report similar to this one:

../_images/report.png

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.

Trigger Deprecation Notices

Deprecation notices can be triggered by using:

@trigger_error('Your deprecation message', E_USER_DEPRECATED);

Without the @-silencing operator, users would need to opt-out from deprecation notices. Silencing by default swaps this behavior and allows users to opt-in when they are ready to cope with them (by adding a custom error handler like the one provided by this bridge). When not silenced, deprecation notices will appear in the Unsilenced section of the deprecation report.

Mark Tests as Legacy

There are four 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*();
  • Make its data provider start with provideLegacy*() or getLegacy*().

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:

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<!-- http://phpunit.de/manual/6.0/en/appendixes.configuration.html -->
<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:noNamespaceSchemaLocation="http://schema.phpunit.de/6.0/phpunit.xsd"
>

    <!-- ... -->

    <php>
        <server name="KERNEL_DIR" value="app/" />
        <env name="SYMFONY_DEPRECATIONS_HELPER" value="/foobar/" />
    </php>
</phpunit>

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 deprecation notices will make tests fail. Alternatively, setting SYMFONY_DEPRECATIONS_HELPER to an arbitrary value (ex: 320) will make the tests fails only if a higher number of deprecation notices is reached (0 is the default value). You can also set the value "weak" which will make the bridge ignore any deprecation notices. This is useful to projects that must use deprecated interfaces for backward compatibility reasons.

Disabling the Deprecation Helper

3.1The ability to disable the deprecation helper was introduced in the 3.1 version of this component.

Set the SYMFONY_DEPRECATIONS_HELPER environment variable to disabled 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

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 @expectedDeprecation annotation 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 annotation several times (order matters):

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/**
 * @group legacy
 * @expectedDeprecation This "%s" method is deprecated.
 * @expectedDeprecation The second argument of the "%s" method is deprecated.
 */
public function testDeprecatedCode()
{
    @trigger_error('This "Foo" method is deprecated.', E_USER_DEPRECATED);
    @trigger_error('The second argument of the "Bar" method is deprecated.', E_USER_DEPRECATED);
}

Time-sensitive Tests

Use Case

If you have this kind of time-related tests:

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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(10, $duration);
    }
}

You used the 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 ClockMock class provided by this bridge allows you to mock the PHP's built-in time functions time(), microtime(), sleep() and usleep().

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:

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<!-- phpunit.xml.dist -->
<!-- ... -->
<listeners>
    <listener class="\Symfony\Bridge\PhpUnit\SymfonyTestsListener" />
</listeners>

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:

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use PHPUnit\Framework\TestCase;
use Symfony\Component\Stopwatch\Stopwatch;

/**
 * @group time-sensitive
 */
class MyTest extends TestCase
{
    public function testSomething()
    {
        $stopwatch = new Stopwatch();

        $stopwatch->start();
        sleep(10);
        $duration = $stopwatch->stop();

        $this->assertEquals(10, $duration);
    }
}

And that's all!

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

3.1The mocks for DNS related functions were introduced in the 3.1 version of this component.

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:

Use Case

Consider the following example that uses the checkMX option of the Email constraint to test the validity of the email domain:

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use PHPUnit\Framework\TestCase;
use Symfony\Component\Validator\Constraints\Email;

class MyTest extends TestCase
{
    public function testEmail()
    {
        $validator = ...
        $constraint = new Email(array('checkMX' => true));

        $result = $validator->validate('foo@example.com', $constraint);

        // ...
}

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:

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use PHPUnit\Framework\TestCase;
use Symfony\Component\Validator\Constraints\Email;

/**
 * @group dns-sensitive
 */
class MyTest extends TestCase
{
    public function testEmails()
    {
        DnsMock::withMockedHosts(array('example.com' => array(array('type' => 'MX'))));

        $validator = ...
        $constraint = new Email(array('checkMX' => true));

        $result = $validator->validate('foo@example.com', $constraint);

        // ...
}

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 dns_get_record, so you can simulate diverse network conditions:

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DnsMock::withMockedHosts(array(
    'example.com' => array(
        array(
            'type' => 'A',
            'ip' => '1.2.3.4',
        ),
        array(
            'type' => 'AAAA',
            'ipv6' => '::12',
        ),
    ),
));

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. that if the your test case 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 HttpKernel Component:

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<!-- http://phpunit.de/manual/4.1/en/appendixes.configuration.html -->
<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:noNamespaceSchemaLocation="http://schema.phpunit.de/4.1/phpunit.xsd"
>

    <!-- ... -->

    <listeners>
        <listener class="Symfony\Bridge\PhpUnit\SymfonyTestsListener">
            <arguments>
                <array>
                    <element key="time-sensitive"><string>Symfony\Component\HttpFoundation</string></element>
                </array>
            </arguments>
        </listener>
    </listeners>
</phpunit>

Modified PHPUnit script

New in version 3.2: This modified PHPUnit script was introduced in the 3.2 version of this component.

This bridge provides a modified version of PHPUnit that you can call by using its bin/simple-phpunit command. It has the following features:

  • Does not embed symfony/yaml nor prophecy to prevent any conflicts with these dependencies;
  • Uses PHPUnit 4.8 when run with PHP <=5.5 and PHPUnit 5.3 when run with PHP >=5.6;
  • 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.

If you have installed the bridge through Composer, you can run it by calling e.g.:

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$ vendor/bin/simple-phpunit

Tip

Set the SYMFONY_PHPUNIT_VERSION env var to e.g. 5.5 to change the base version of PHPUnit to 5.5 instead of the default 5.3.

Tip

If you still need to use prophecy (but not symfony/yaml), then set the SYMFONY_PHPUNIT_REMOVE env var to symfony/yaml.

This work, including the code samples, is licensed under a Creative Commons BY-SA 3.0 license.