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Writing functional tests


Functional testing in TYPO3 world is basically the opposite of unit testing: Instead of looking at rather small, isolated pieces of code, functional testing looks at bigger scenarios with many involved dependencies. A typical scenario creates a full instance with some extensions, puts some rows into the database and calls an entry method, for instance a controller action. That method triggers dependent logic that changes data. The tests end with comparing the changed data or output is identical to some expected data.

This chapter goes into details on functional testing and how the typo3/testing-framework helps with setting up, running and verifying scenarios.


Functional testing is much about defining the specific scenario that should be set up by the system and isolating it from other scenarios. The basic thinking is that a single scenario that involves a set of loaded extensions, maybe some files and some database rows is a single test case (= one test file), and one or more single tests are executed using this scenario definition.

Single test cases extend TYPO3\TestingFramework\Core\Functional\FunctionalTestCase. The default implementation of method setUp() contains all the main magic to set up a new TYPO3 instance in a sub folder of the existing system, create a database, create LocalConfiguration.php, load extensions, populate the database with tables needed by the extensions and to link or copy additional fixture files around and finally bootstrap a basic TYPO3 backend. setUp() is called before each test, so each single test is isolated from other tests, even within one test case. There is only one optimization step: The instance between single tests of one test case is not fully created from scratch, but the existing instance is just cleaned up (all database tables truncated). This is a measure to speed up execution, but still, the general thinking is that each test stands for it's own and should not have side effects on other tests.

The TYPO3\TestingFramework\Core\Functional\FunctionalTestCase contains a series of class properties. Most of them are designed to be overwritten by single test cases, they tell setUp() what to do. For instance, there is a property to specify which extensions should be active for the given scenario. Everyone looking or creating functional tests should have a look at these properties: They are well documented and contain examples how to use. These properties are the key to instruct typo3/testing-framework what to do.

The "external dependencies" like credentials for the database are submitted as environment variables. If using the recommended docker based setup to execute tests, these details are taken care off by the and docker-compose.yml files. See the styleguide example for details on how this is set up and used. Executing the functional tests on different databases is handled by these and it is possible to run one tests on different databases by calling with the according options to do this. The above chapter Extension testing is about executing tests and setting up the runtime, while this chapter is about writing tests and setting up the scenario.

Simple Example

At the time of this writing, TYPO3 core contains more than 2600 functional tests, so there are plenty of test files to look at to learn about writing functional tests. Do not hesitate looking around, there is plenty to discover.

As a starter, let's have a look at a basic scenario from the styleguide example again:

namespace TYPO3\CMS\Styleguide\Tests\Functional\TcaDataGenerator;

use TYPO3\CMS\Core\Core\Bootstrap;
use TYPO3\CMS\Styleguide\TcaDataGenerator\Generator;
use TYPO3\TestingFramework\Core\Functional\FunctionalTestCase;

 * Test case
class GeneratorTest extends FunctionalTestCase
     * @var array Have styleguide loaded
    protected $testExtensionsToLoad = [

     * @test
     * @group not-mssql
    public function generatorCreatesBasicRecord()

That's the basic setup needed for a functional test: Extend FunctionalTestCase, declare extension styleguide should be loaded and have a first test.

Extending setUp

Note setUp() is not overridden in this case. If you override it, remember to always call parent::setUp() before doing own stuff. An example can be found in TYPO3\CMS\Backend\Tests\Functional\Domain\Repository\LocalizationLocalizationRepositoryTest:

declare(strict_types = 1);
namespace TYPO3\CMS\Backend\Tests\Functional\Domain\Repository\Localization;

use TYPO3\CMS\Backend\Domain\Repository\Localization\LocalizationRepository;
use TYPO3\CMS\Core\Core\Bootstrap;
use TYPO3\TestingFramework\Core\Functional\FunctionalTestCase;

 * Test case
class LocalizationRepositoryTest extends FunctionalTestCase
     * @var LocalizationRepository
    protected $subject;

     * Sets up this test case.
    protected function setUp(): void


        $this->importCSVDataSet(ORIGINAL_ROOT . 'typo3/sysext/backend/Tests/Functional/Domain/Repository/Localization/Fixtures/DefaultPagesAndContent.csv');

        $this->subject = new LocalizationRepository();


The above example overrides setUp() to first call parent::setUp(). This is critically important to do, if not done the entire test instance set up is not triggered. After calling parent, various things needed by all tests of this scenario are added: A database fixtures is loaded, a backend user is added, the language object is initialized and an instance of the system under test is parked as $this->subject within the class.

Loaded extensions

The FunctionalTestCase has a couple of defaults and properties to specify the set of loaded extensions of a test case: First, there is a set of default core extensions that are always loaded. Those should be require or at least require-dev dependencies in a composer.json file, too: core, backend, frontend, extbase, install and recordlist.

Apart from that default list, it is possible to load additional core extensions, an extension that wants to test if it works well together with workspaces, would for example specify the workspaces extension as additional to-load extension:

protected $coreExtensionsToLoad = [

Furthermore, non-core extensions and fixture extensions can be loaded for any given test case:

protected $testExtensionsToLoad = [

In this case the fictive extension some_extension comes with an own fixture extension that should be loaded, and another base_extension should be loaded. These extensions will be linked into typo3conf/ext of the test case instance.

The functional test bootstrap links all extensions to either typo3/sysext for core extensions or typo3conf/ext for non-core extensions, creates a PackageStates.php and then uses the database schema analyzer to create all database tables specified in the ext_tables.sql files.

Database fixtures

To populate the test database tables with rows to prepare any given scenario, the helper method $this->importCSVDataSet() can be used. Note it is not possible to inject a fully prepared database, for instance it is not possible to provide a full .sqlite database and work on this in the test case. Instead, database rows should be provided as .csv files to be loaded into the database using $this->importCSVDataSet(). An example file could look like this:

,1,0,256,0,0,"Connected mode",,,
,297,1,256,0,0,0,0,0,"Regular Element #1"

This file defines one row for the pages table, two rows for the sys_language table and finally one tt_content row. So one .csv file can contain rows of multiple tables.

There is a similar method called $this->importDataSet() that allows loading database rows defined as XML instead of CSV, too.

In general, the methods need the absolute path to the fixture file to load them. However some keywords are allowed:

// Load a xml file relative to test case file
$this->importDataSet(__DIR__ . '/../Fixtures/pages.xml');
// Load a xml file of some extension
// Load a xml file provided by the typo3/testing-framework package

Asserting database

A test that triggered some data munging in the database probably wants to test if the final state of some rows in the database is as expected after the job is done. The helper method assertCSVDataSet() helps to do that. As in the .csv example above, it needs the absolute path to some CSV file that can contain rows of multiple tables. The methods will then look up the according rows in the database and compare their values with the fields provided in the CSV files. If they are not identical, the test will fail and output a table which field values did not match.

Loading files

If the system under test works on files, those can be provided by the test setup, too. As example, one may want to check if an image has been properly sized down. The image to work on can be linked into the test instance:

 * @var array
protected $pathsToLinkInTestInstance = [
    'typo3/sysext/impexp/Tests/Functional/Fixtures/Folders/fileadmin/user_upload/typo3_image2.jpg' => 'fileadmin/user_upload/typo3_image2.jpg',

It is also possible to copy the files to the test instance instead of only linking it using $pathsToProvideInTestInstance.


A default LocalConfiguration.php file of the instance is created by the default setUp(). It contains the database credentials and everything else to end up with a working TYPO3 instance.

If extensions need additional settings in LocalConfiguration.php, the property $configurationToUseInTestInstance can be used to specify these:

protected $configurationToUseInTestInstance = [
    'MAIL' => [
        'transport' => \Symfony\Component\Mailer\Transport\NullTransport::class,

Frontend tests


Frontend functional testing is currently still a subject to change and the core did not fully settle in this area, yet. The docs below outline only the bare minimum to set up and execute these tests and core usages are hard to explain here in detail since most of them work with additional abstracts and set up tricks.

To prepare a frontend test, the system can be instructed to load a set of .typoscript files for a working frontend:

$this->setUpFrontendRootPage(1, ['EXT:fluid_test/Configuration/TypoScript/Basic.ts']);

This instructs the system to load the Basic.ts as typoscript file for the frontend page with uid 1.

A frontend request can be executed calling $this->executeFrontendRequest(). It will return a Response object to be further worked on, for instance it is possible to verify if the body ->getBody() contains some string.