Whenever you write a new line of code, you also potentially add new bugs. To build better and more reliable applications, you should test your code using both functional and unit tests.

The PHPUnit Testing Framework

Symfony integrates with an independent library called PHPUnit to give you a rich testing framework. This article won’t cover PHPUnit itself, which has its own excellent documentation.

Before creating your first test, install phpunit/phpunit and the symfony/test-pack, which installs some other packages providing useful Symfony test utilities:

$ composer require --dev phpunit/phpunit symfony/test-pack

After the library is installed, try running PHPUnit:

$ php ./vendor/bin/phpunit

This commands automatically runs your application’s tests. Each test is a PHP class ending with “Test” (e.g. BlogControllerTest) that lives in the tests/ directory of your application.

PHPUnit is configured by the phpunit.xml.dist file in the root of your application. The default configuration provided by Symfony Flex will be enough in most cases. Read the PHPUnit documentation to discover all possible configuration options (e.g. to enable code coverage or to split your test into multiple “test suites”).


Symfony Flex automatically creates phpunit.xml.dist and tests/bootstrap.php. If these files are missing, you can try running the recipe again using composer recipes:install phpunit/phpunit --force -v.

Types of Tests

There are many types of automated tests and precise definitions often differ from project to project. In Symfony, the following definitions are used. If you have learned something different, that is not necessarily wrong, just different from what the Symfony documentation is using.

Unit Tests
These tests ensure that individual units of source code (e.g. a single class) behave as intended.
Integration Tests
These tests test a combination of classes and commonly interact with Symfony’s service container. These tests do not yet cover the fully working application, those are called Application tests.
Application Tests
Application tests test the behavior of a complete application. They make HTTP requests (both real and simulated ones) and test that the response is as expected.

Unit Tests

A unit test ensures that individual units of source code (e.g. a single class or some specific method in some class) meet their design and behave as intended. Writing unit tests in a Symfony application is no different from writing standard PHPUnit unit tests. You can learn about it in the PHPUnit documentation: Writing Tests for PHPUnit.

By convention, the tests/ directory should replicate the directory of your application for unit tests. So, if you’re testing a class in the src/Form/ directory, put the test in the tests/Form/ directory. Autoloading is automatically enabled via the vendor/autoload.php file (as configured by default in the phpunit.xml.dist file).

You can run tests using the ./vendor/bin/phpunit command:

# run all tests of the application
$ php ./vendor/bin/phpunit

# run all tests in the Form/ directory
$ php ./vendor/bin/phpunit tests/Form

# run tests for the UserType class
$ php ./vendor/bin/phpunit tests/Form/UserTypeTest.php


In large test suites, it can make sense to create subdirectories for each type of tests (e.g. tests/Unit/ and test/Functional/).

Integration Tests

An integration test will test a larger part of your application compared to a unit test (e.g. a combination of services). Integration tests might want to use the Symfony Kernel to fetch a service from the dependency injection container.

Symfony provides a Symfony\Bundle\FrameworkBundle\Test\KernelTestCase class to help you creating and booting the kernel in your tests using bootKernel():

// tests/Service/NewsletterGeneratorTest.php
namespace App\Tests\Service;

use Symfony\Bundle\FrameworkBundle\Test\KernelTestCase;

class NewsletterGeneratorTest extends KernelTestCase
    public function testSomething()

        // ...

The KernelTestCase also makes sure your kernel is rebooted for each test. This assures that each test is run independently from each other.

To run your application tests, the KernelTestCase class needs to find the application kernel to initialize. The kernel class is usually defined in the KERNEL_CLASS environment variable (included in the default .env.test file provided by Symfony Flex):

# .env.test


If your use case is more complex, you can also override the getKernelClass() or createKernel() methods of your functional test, which take precedence over the KERNEL_CLASS env var.

Set-up your Test Environment

The tests create a kernel that runs in the test environment. This allows to have special settings for your tests inside config/packages/test/.

If you have Symfony Flex installed, some packages already installed some useful test configuration. For example, by default, the Twig bundle is configured to be especially strict to catch errors before deploying your code to production:

  • YAML
    # config/packages/test/twig.yaml
        strict_variables: true
  • XML
    <!-- config/packages/test/twig.xml -->
    <?xml version="1.0" encoding="UTF-8" ?>
    <container xmlns="http://symfony.com/schema/dic/services"
        <framework:config strict-variables="true"/>
  • PHP
    // config/packages/test/twig.php
    $container->loadFromExtension('twig', [
        'strict_variables' => true,

You can also use a different environment entirely, or override the default debug mode (true) by passing each as options to the bootKernel() method:

    'environment' => 'my_test_env',
    'debug'       => false,


It is recommended to run your test with debug set to false on your CI server, as it significantly improves test performance. This disables clearing the cache. If your tests don’t run in a clean environment each time, you have to manually clear it using for instance this code in tests/bootstrap.php:

// ...

// ensure a fresh cache when debug mode is disabled
(new \Symfony\Component\Filesystem\Filesystem())->remove(__DIR__.'/../var/cache/test');

Customizing Environment Variables

If you need to customize some environment variables for your tests (e.g. the DATABASE_URL used by Doctrine), you can do that by overriding anything you need in your .env.test file:

# .env.test

# ...
DATABASE_URL="mysql://db_user:[email protected]:3306/db_name_test?serverVersion=5.7"

In the test environment, these env files are read (if vars are duplicated in them, files lower in the list override previous items):

  1. .env: containing env vars with application defaults;
  2. .env.test: overriding/setting specific test values or vars;
  3. .env.test.local: overriding settings specific for this machine.


The .env.local file is not used in the test environment, to make each test set-up as consistent as possible.

Retrieving Services in the Test

In your integration tests, you often need to fetch the service from the service container to call a specific method. After booting the kernel, the container is stored in self::$container:

// tests/Service/NewsletterGeneratorTest.php
namespace App\Tests\Service;

use App\Service\NewsletterGenerator;
use Symfony\Bundle\FrameworkBundle\Test\KernelTestCase;

class NewsletterGeneratorTest extends KernelTestCase
    public function testSomething()
        // (1) boot the Symfony kernel

        // (2) use self::$container to access the service container
        $container = self::$container;

        // (3) run some service & test the result
        $newsletterGenerator = $container->get(NewsletterGenerator::class);
        $newsletter = $newsletterGenerator->generateMonthlyNews(...);

        $this->assertEquals(..., $newsletter->getContent());

The container in self::$container is actually a special test container. It gives you access to both the public services and the non-removed private services services.


If you need to test private services that have been removed (those who are not used by any other services), you need to declare those private services as public in the config/services_test.yaml file.

Configuring a Database for Tests

Tests that interact with the database should use their own separate database to not mess with the databases used in the other configuration environments.

To do that, edit or create the .env.test.local file at the root directory of your project and define the new value for the DATABASE_URL env var:

# .env.test.local
DATABASE_URL="mysql://USERNAME:[email protected]:3306/DB_NAME?serverVersion=5.7"

This assumes that each developer/machine uses a different database for the tests. If the test set-up is the same on each machine, use the .env.test file instead and commit it to the shared repository. Learn more about using multiple .env files in Symfony applications.

After that, you can create the test database and all tables using:

# create the test database
$ php bin/console --env=test doctrine:database:create

# create the tables/columns in the test database
$ php bin/console --env=test doctrine:schema:create


A common practice is to append the _test suffix to the original database names in tests. If the database name in production is called project_acme the name of the testing database could be project_acme_test.

Resetting the Database Automatically Before each Test

Tests should be independent from each other to avoid side effects. For example, if some test modifies the database (by adding or removing an entity) it could change the results of other tests.

The DAMADoctrineTestBundle uses Doctrine transactions to let each test interact with an unmodified database. Install it using:

$ composer require --dev dama/doctrine-test-bundle

Now, enable it as a PHPUnit extension:

<!-- phpunit.xml.dist -->
    <!-- ... -->

        <extension class="DAMA\DoctrineTestBundle\PHPUnit\PHPUnitExtension"/>

That’s it! This bundle uses a clever trick: it begins a database transaction before every test and rolls it back automatically after the test finishes to undo all changes. Read more in the documentation of the DAMADoctrineTestBundle.

Load Dummy Data Fixtures

Instead of using the real data from the production database, it’s common to use fake or dummy data in the test database. This is usually called “fixtures data” and Doctrine provides a library to create and load them. Install it with:

$ composer require --dev doctrine/doctrine-fixtures-bundle

Then, use the make:fixtures command of the SymfonyMakerBundle to generate an empty fixture class:

$ php bin/console make:fixtures

The class name of the fixtures to create (e.g. AppFixtures):
> ProductFixture

Then you modify use this class to load new entities in the database. For instance, to load Product objects into Doctrine, use:

// src/DataFixtures/ProductFixture.php
namespace App\DataFixtures;

use App\Entity\Product;
use Doctrine\Bundle\FixturesBundle\Fixture;
use Doctrine\Persistence\ObjectManager;

class ProductFixture extends Fixture
    public function load(ObjectManager $manager)
        $product = new Product();
        $product->setName('Priceless widget');
        $product->setDescription('Ok, I guess it *does* have a price');

        // add more products


Empty the database and reload all the fixture classes with:

$ php bin/console doctrine:fixtures:load

For more information, read the DoctrineFixturesBundle documentation.

Application Tests

Application tests check the integration of all the different layers of the application (from the routing to the views). They are no different from unit tests or integration tests as far as PHPUnit is concerned, but they have a very specific workflow:

  1. Make a request;
  2. Interact with the page (e.g. click on a link or submit a form);
  3. Test the response;
  4. Rinse and repeat.


The tools used in this section can be installed via the symfony/test-pack, use composer require symfony/test-pack if you haven’t done so already.

Write Your First Application Test

Application tests are PHP files that typically live in the tests/Controller/ directory of your application. They often extend Symfony\Bundle\FrameworkBundle\Test\WebTestCase. This class adds special logic on top of the KernelTestCase. You can read more about that in the above section on integration tests.

If you want to test the pages handled by your PostController class, start by creating a new PostControllerTest using the make:test command of the SymfonyMakerBundle:

$ php bin/console make:test

 Which test type would you like?:
 > WebTestCase

 The name of the test class (e.g. BlogPostTest):
 > Controller\PostControllerTest

This creates the following test class:

// tests/Controller/PostControllerTest.php
namespace App\Tests\Controller;

use Symfony\Bundle\FrameworkBundle\Test\WebTestCase;

class PostControllerTest extends WebTestCase
    public function testSomething(): void
        // This calls KernelTestCase::bootKernel(), and creates a
        // "client" that is acting as the browser
        $client = static::createClient();

        // Request a specific page
        $crawler = $client->request('GET', '/');

        // Validate a successful response and some content
        $this->assertSelectorTextContains('h1', 'Hello World');

In the above example, the test validates that the HTTP response was successful and the request body contains a <h1> tag with "Hello world".

The request() method also returns a crawler, which you can use to create more complex assertions in your tests:

$crawler = $client->request('GET', '/post/hello-world');

// for instance, count the number of ``.comment`` elements on the page
$this->assertCount(4, $crawler->filter('.comment'));

You can learn more about the crawler in The DOM Crawler.

Making Requests

The test client simulates an HTTP client like a browser and makes requests into your Symfony application:

$crawler = $client->request('GET', '/post/hello-world');

The request() method takes the HTTP method and a URL as arguments and returns a Crawler instance.


Hardcoding the request URLs is a best practice for application tests. If the test generates URLs using the Symfony router, it won’t detect any change made to the application URLs which may impact the end users.

The full signature of the request() method is:

    array $parameters = [],
    array $files = [],
    array $server = [],
    $content = null,
    $changeHistory = true

This allows you to create all types of requests you can think of:


The test client is available as the test.client service in the container in the test environment (or wherever the framework.test option is enabled). This means you can override the service entirely if you need to.

Browsing the Site

The Client supports many operations that can be done in a real browser:


// clears all cookies and the history


The back() and forward() methods skip the redirects that may have occurred when requesting a URL, as normal browsers do.


When a request returns a redirect response, the client does not follow it automatically. You can examine the response and force a redirection afterwards with the followRedirect() method:

$crawler = $client->followRedirect();

If you want the client to automatically follow all redirects, you can force them by calling the followRedirects() method before performing the request:


If you pass false to the followRedirects() method, the redirects will no longer be followed:


Making AJAX Requests

The client provides a xmlHttpRequest() method, which has the same arguments as the request() method and is a shortcut to make AJAX requests:

// the required HTTP_X_REQUESTED_WITH header is added automatically
$client->xmlHttpRequest('POST', '/submit', ['name' => 'Fabien']);

Sending Custom Headers

If your application behaves according to some HTTP headers, pass them as the second argument of createClient():

$client = static::createClient([], [
    'HTTP_HOST'       => 'en.example.com',
    'HTTP_USER_AGENT' => 'MySuperBrowser/1.0',

You can also override HTTP headers on a per request basis:

$client->request('GET', '/', [], [], [
    'HTTP_HOST'       => 'en.example.com',
    'HTTP_USER_AGENT' => 'MySuperBrowser/1.0',


The name of your custom headers must follow the syntax defined in the section 4.1.18 of RFC 3875: replace - by _, transform it into uppercase and prefix the result with HTTP_. For example, if your header name is X-Session-Token, pass HTTP_X_SESSION_TOKEN.

Reporting Exceptions

Debugging exceptions in application tests may be difficult because by default they are caught and you need to look at the logs to see which exception was thrown. Disabling catching of exceptions in the test client allows the exception to be reported by PHPUnit:


Accessing Internal Objects

If you use the client to test your application, you might want to access the client’s internal objects:

$history = $client->getHistory();
$cookieJar = $client->getCookieJar();

You can also get the objects related to the latest request:

// the HttpKernel request instance
$request = $client->getRequest();

// the BrowserKit request instance
$request = $client->getInternalRequest();

// the HttpKernel response instance
$response = $client->getResponse();

// the BrowserKit response instance
$response = $client->getInternalResponse();

// the Crawler instance
$crawler = $client->getCrawler();

Accessing the Profiler Data

On each request, you can enable the Symfony profiler to collect data about the internal handling of that request. For example, the profiler could be used to verify that a given page runs less than a certain number of database queries when loading.

To get the profiler for the last request, do the following:

// enables the profiler for the very next request

$crawler = $client->request('GET', '/profiler');

// gets the profile
$profile = $client->getProfile();

For specific details on using the profiler inside a test, see the How to Use the Profiler in a Functional Test article.

Interacting with the Response

Like a real browser, the Client and Crawler objects can be used to interact with the page you’re served:

Submitting Forms

Use the submitForm() method to submit the form that contains the given button:

$client = static::createClient();
$client->request('GET', '/post/hello-world');

$crawler = $client->submitForm('Add comment', [
    'comment_form[content]' => '...',

The first argument of submitForm() is the text content, id, value or name of any <button> or <input type="submit"> included in the form. The second optional argument is used to override the default form field values.


Notice that you select form buttons and not forms, as a form can have several buttons. If you use the traversing API, keep in mind that you must look for a button.

If you need access to the Symfony\Component\DomCrawler\Form object that provides helpful methods specific to forms (such as getUri(), getValues() and getFields()) use the Crawler::selectButton() method instead:

$client = static::createClient();
$crawler = $client->request('GET', '/post/hello-world');

// select the button
$buttonCrawlerNode = $crawler->selectButton('submit');

// retrieve the Form object for the form belonging to this button
$form = $buttonCrawlerNode->form();

// set values on a form object
$form['my_form[name]'] = 'Fabien';
$form['my_form[subject]'] = 'Symfony rocks!';

// submit the Form object

// optionally, you can combine the last 2 steps by passing an array of
// field values while submitting the form:
$client->submit($form, [
    'my_form[name]'    => 'Fabien',
    'my_form[subject]' => 'Symfony rocks!',

Based on the form type, you can use different methods to fill in the input:

// selects an option or a radio

// ticks a checkbox

// uploads a file

// In the case of a multiple file upload


Instead of hardcoding the form name as part of the field names (e.g. my_form[...] in previous examples), you can use the getName() method to get the form name.

New in version 4.4: The getName() method was introduced in Symfony 4.4.


If you purposefully want to select “invalid” select/radio values, see Selecting Invalid Choice Values.


You can get the values that will be submitted by calling the getValues() method on the Form object. The uploaded files are available in a separate array returned by getFiles(). The getPhpValues() and getPhpFiles() methods also return the submitted values, but in the PHP format (it converts the keys with square brackets notation - e.g. my_form[subject] - to PHP arrays).


The submit() and submitForm() methods define optional arguments to add custom server parameters and HTTP headers when submitting the form:

$client->submit($form, [], ['HTTP_ACCEPT_LANGUAGE' => 'es']);
$client->submitForm($button, [], 'POST', ['HTTP_ACCEPT_LANGUAGE' => 'es']);

Testing the Response (Assertions)

Now that the tests have visited a page and interacted with it (e.g. filled in a form), it is time to verify that the expected output is shown.

As all tests are based on PHPUnit, you can use any PHPUnit Assertion in your tests. Combined with test Client and the Crawler, this allows you to check anything you want.

However, Symfony provides useful shortcut methods for the most common cases:

New in version 4.3: The shortcut methods for assertions using WebTestCase were introduced in Symfony 4.3.

New in version 4.4: Starting from Symfony 4.4, when using symfony/panther for end-to-end testing, you can use all the following assertions except the ones related to the Crawler.

Response Assertions

assertResponseIsSuccessful(string $message = '')
Asserts that the response was successful (HTTP status is 2xx).
assertResponseStatusCodeSame(int $expectedCode, string $message = '')
Asserts a specific HTTP status code.
assertResponseRedirects(string $expectedLocation = null, int $expectedCode = null, string $message = '')
Asserts the response is a redirect response (optionally, you can check the target location and status code).
assertResponseHasHeader(string $headerName, string $message = '')/assertResponseNotHasHeader(string $headerName, string $message = '')
Asserts the given header is (not) available on the response.
assertResponseHeaderSame(string $headerName, string $expectedValue, string $message = '')/assertResponseHeaderNotSame(string $headerName, string $expectedValue, string $message = '')
Asserts the given header does (not) contain the expected value on the response.
assertResponseHasCookie(string $name, string $path = '/', string $domain = null, string $message = '')/assertResponseNotHasCookie(string $name, string $path = '/', string $domain = null, string $message = '')
Asserts the given cookie is present in the response (optionally checking for a specific cookie path or domain).
assertResponseCookieValueSame(string $name, string $expectedValue, string $path = '/', string $domain = null, string $message = '')
Asserts the given cookie is present and set to the expected value.

Request Assertions

assertRequestAttributeValueSame(string $name, string $expectedValue, string $message = '')
Asserts the given request attribute is set to the expected value.
assertRouteSame($expectedRoute, array $parameters = [], string $message = '')
Asserts the request matched the given route and optionally route parameters.

Browser Assertions

assertBrowserHasCookie(string $name, string $path = '/', string $domain = null, string $message = '')/assertBrowserNotHasCookie(string $name, string $path = '/', string $domain = null, string $message = '')
Asserts that the test Client does (not) have the given cookie set (meaning, the cookie was set by any response in the test).
assertBrowserCookieValueSame(string $name, string $expectedValue, string $path = '/', string $domain = null, string $message = '')
Asserts the given cookie in the test Client is set to the expected value.

Crawler Assertions

assertSelectorExists(string $selector, string $message = '')/assertSelectorNotExists(string $selector, string $message = '')
Asserts that the given selector does (not) match at least one element in the response.
assertSelectorTextContains(string $selector, string $text, string $message = '')/assertSelectorTextNotContains(string $selector, string $text, string $message = '')
Asserts that the first element matching the given selector does (not) contain the expected text.
assertSelectorTextSame(string $selector, string $text, string $message = '')
Asserts that the contents of the first element matching the given selector does (not) equal the expected text.
assertPageTitleSame(string $expectedTitle, string $message = '')
Asserts that the <title> element is equal to the given title.
assertPageTitleContains(string $expectedTitle, string $message = '')
Asserts that the <title> element contains the given title.
assertInputValueSame(string $fieldName, string $expectedValue, string $message = '')/assertInputValueNotSame(string $fieldName, string $expectedValue, string $message = '')
Asserts that value of the form input with the given name does (not) equal the expected value.

Mailer Assertions

New in version 4.4: The mailer assert methods were introduced in Symfony 4.4.

assertEmailCount(int $count, string $transport = null, string $message = '')
Asserts that the expected number of emails was sent.
assertQueuedEmailCount(int $count, string $transport = null, string $message = '')
Asserts that the expected number of emails was queued (e.g. using the Messenger component).
assertEmailIsQueued(MessageEvent $event, string $message = '')/assertEmailIsNotQueued(MessageEvent $event, string $message = '')
Asserts that the given mailer event is (not) queued. Use getMailerEvent(int $index = 0, string $transport = null) to retrieve a mailer event by index.
assertEmailAttachmentCount(RawMessage $email, int $count, string $message = '')
Asserts that the given email has the expected number of attachments. Use getMailerMessage(int $index = 0, string $transport = null) to retrievea specific email by index.
assertEmailTextBodyContains(RawMessage $email, string $text, string $message = '')/assertEmailTextBodyNotContains(RawMessage $email, string $text, string $message = '')
Asserts that the text body of the given email does (not) contain the expected text.
assertEmailHtmlBodyContains(RawMessage $email, string $text, string $message = '')/assertEmailHtmlBodyNotContains(RawMessage $email, string $text, string $message = '')
Asserts that the HTML body of the given email does (not) contain the expected text.
assertEmailHasHeader(RawMessage $email, string $headerName, string $message = '')/assertEmailNotHasHeader(RawMessage $email, string $headerName, string $message = '')
Asserts that the given email does (not) have the expected header set.
assertEmailHeaderSame(RawMessage $email, string $headerName, string $expectedValue, string $message = '')/assertEmailHeaderNotSame(RawMessage $email, string $headerName, string $expectedValue, string $message = '')
Asserts that the given email does (not) have the expected header set to the expected value.
assertEmailAddressContains(RawMessage $email, string $headerName, string $expectedValue, string $message = '')
Asserts that the given address header equals the expected e-mail address. This assertion normalizes addresses like Jane Smith <jane@example.com> into jane@example.com.

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