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SymfonyDependencyInjectionTest

By Matthias Noback and contributors

This library contains several PHPUnit test case classes and many semantic assertions which you can use to functionally test your container extensions (or "bundle extensions") and compiler passes. It also provides the tools to functionally test your container extension (or "bundle") configuration by verifying processed values from different types of configuration files.

Besides verifying their correctness, this library will also help you to adopt a TDD approach when developing these classes.

Installation

Using Composer:

composer require --dev matthiasnoback/symfony-dependency-injection-test

Usage

Testing a container extension

To test your own container extension class MyExtension create a class and extend from Matthias\SymfonyDependencyInjectionTest\PhpUnit\AbstractExtensionTestCase. Then implement the getContainerExtensions() method:

<?php

use Matthias\SymfonyDependencyInjectionTest\PhpUnit\AbstractExtensionTestCase;

class MyExtensionTest extends AbstractExtensionTestCase
{
    protected function getContainerExtensions(): array
    {
        return [
            new MyExtension()
        ];
    }
}

Basically you will be testing your extension's load method, which will look something like this:

<?php

class MyExtension extends Extension
{
    public function load(array $config, ContainerBuilder $container)
    {
        $loader = new XmlFileLoader($container, new FileLocator(__DIR__));
        $loader->load('services.xml');

        // maybe process the configuration values in $config, then:

        $container->setParameter('parameter_name', 'some value');
    }
}

So in the test case you should test that after loading the container, the parameter has been set correctly:

<?php

class MyExtensionTest extends AbstractExtensionTestCase
{
    /**
     * @test
     */
    public function after_loading_the_correct_parameter_has_been_set()
    {
        $this->load();

        $this->assertContainerBuilderHasParameter('parameter_name', 'some value');
    }
}

To test the effect of different configuration values, use the first argument of load():

<?php

class MyExtensionTest extends AbstractExtensionTestCase
{
    /**
     * @test
     */
    public function after_loading_the_correct_parameter_has_been_set()
    {
        $this->load(['my' => ['enabled' => 'false']);

        ...
    }
}

To prevent duplication of required configuration values, you can provide some minimal configuration, by overriding the getMinimalConfiguration() method of the test case.

Testing a compiler pass

To test a compiler pass, create a test class and extend from Matthias\SymfonyDependencyInjectionTest\PhpUnit\AbstractCompilerPassTestCase. Then implement the registerCompilerPass() method:

<?php

use Matthias\SymfonyDependencyInjectionTest\PhpUnit\AbstractCompilerPassTestCase;

class MyCompilerPassTest extends AbstractCompilerPassTestCase
{
    protected function registerCompilerPass(ContainerBuilder $container): void
    {
        $container->addCompilerPass(new MyCompilerPass());
    }
}

In each test you can first set up the ContainerBuilder instance properly, depending on what your compiler pass is expected to do. For instance you can add some definitions with specific tags you will collect. Then after the "arrange" phase of your test, you need to "act", by calling the compile()method. Finally you may enter the "assert" stage and you should verify the correct behavior of the compiler pass by making assertions about the ContainerBuilder instance.

<?php

class MyCompilerPassTest extends AbstractCompilerPassTestCase
{
    /**
     * @test
     */
    public function if_compiler_pass_collects_services_by_adding_method_calls_these_will_exist()
    {
        $collectingService = new Definition();
        $this->setDefinition('collecting_service_id', $collectingService);

        $collectedService = new Definition();
        $collectedService->addTag('collect_with_method_calls');
        $this->setDefinition('collected_service', $collectedService);

        $this->compile();

        $this->assertContainerBuilderHasServiceDefinitionWithMethodCall(
            'collecting_service_id',
            'add',
            [
                new Reference('collected_service')
            ]
        );
    }
}

Standard test for unobtrusiveness

The AbstractCompilerPassTestCase class always executes one specific test - compilation_should_not_fail_with_empty_container() - which makes sure that the compiler pass is unobtrusive. For example, when your compiler pass assumes the existence of a service, an exception will be thrown, and this test will fail:

<?php

use Symfony\Component\DependencyInjection\Compiler\CompilerPassInterface;
use Symfony\Component\DependencyInjection\ContainerBuilder;

class MyCompilerPass implements CompilerPassInterface
{
    public function process(ContainerBuilder $container)
    {
        $definition = $container->getDefinition('some_service_id');

        ...
    }
}

So you need to always add one or more guard clauses inside the process() method:

<?php

use Symfony\Component\DependencyInjection\Compiler\CompilerPassInterface;
use Symfony\Component\DependencyInjection\ContainerBuilder;

class MyCompilerPass implements CompilerPassInterface
{
    public function process(ContainerBuilder $container)
    {
        if (!$container->hasDefinition('some_service_id')) {
            return;
        }

        $definition = $container->getDefinition('some_service_id');

        ...
    }
}

Use findDefinition() instead of getDefinition()

You may not know in advance if a service id stands for a service definition, or for an alias. So instead of hasDefinition() and getDefinition() you may consider using has() and findDefinition(). These methods recognize both aliases and definitions.

Test different configuration file formats

The Symfony DependencyInjection component supports many different types of configuration loaders: Yaml, XML, and PHP files, but also closures. When you create a Configuration class for your bundle, you need to make sure that each of these formats is supported. Special attention needs to be given to XML files.

In order to verify that any type of configuration file will be correctly loaded by your bundle, you must install the SymfonyConfigTest library and create a test class that extends from AbstractExtensionConfigurationTestCase:

<?php

use Matthias\SymfonyDependencyInjectionTest\PhpUnit\AbstractExtensionConfigurationTestCase;

class ConfigurationTest extends AbstractExtensionConfigurationTestCase
{
    protected function getContainerExtension()
    {
        return new TwigExtension();
    }

    protected function getConfiguration()
    {
        return new Configuration();
    }
}

Now inside each test method you can use the assertProcessedConfigurationEquals($expectedConfiguration, $sources) method to verify that after loading the given sources the processed configuration equals the expected array of values:

# in Fixtures/config.yml
twig:
    extensions: ['twig.extension.foo']

<!-- in Fixtures/config.xml -->
<container>
    <twig:config>
        <twig:extension>twig.extension.bar</twig:extension>
    </twig:config>
</container>

<?php
...

class ConfigurationTest extends AbstractExtensionConfigurationTestCase
{
    ...

    /**
     * @test
     */
    public function it_converts_extension_elements_to_extensions()
    {
        $expectedConfiguration = [
            'extensions' => ['twig.extension.foo', 'twig.extension.bar']
        ];

        $sources = [
            __DIR__ . '/Fixtures/config.yml',
            __DIR__ . '/Fixtures/config.xml',
        ];

        $this->assertProcessedConfigurationEquals($expectedConfiguration, $sources);
    }
}

List of assertions

These are the available semantic assertions for each of the test cases shown above:

Available methods to set up container

In all test cases shown above, you have access to some methods to set up the container:

Version Guidance