Unable to test `$GLOBALS['TYPO3_CONF_VARS']['EXTENSIONS']` settings within functinal tests

[dkd-kaehm]

What are you trying to achieve?

I'm trying to setup the functional test considering the extension settings by using \TYPO3\TestingFramework\Core\Functional\FunctionalTestCase::$configurationToUseInTestInstance property.

The properties description complains about merging but it overrules to unusable state:

testing-framework/Classes/Core/Functional/FunctionalTestCase.php

Lines 222 to 228 in 1530ae5

	/**
	* This configuration array is merged with TYPO3_CONF_VARS
	* that are set in default configuration and factory configuration
	*
	* @var array<string, mixed>
	*/
	protected array $configurationToUseInTestInstance = [];

What do you get instead?

The property overrules all the settings instead of merge them, so following lines are written
to $instancePath . '/typo3conf/system/settings.php' file.
The functionality with additional.php like on core is not possible in testing-framework.

testing-framework/Classes/Core/Testbase.php

Lines 567 to 575 in e9c3bc4

	$result = @file_put_contents(
	$instancePath . '/typo3conf/system/settings.php',
	'<?php' . chr(10) .
	'return ' .
	ArrayUtility::arrayExport(
	$finalConfigurationArray
	) .
	';'
	);

How to reproduce the issue?

Include some $GLOBALS['TYPO3_CONF_VARS']['EXTENSIONS']['your_ext']['someSetting'] = 1 and try to use other default settings from this extension configured in ext_conf_template.txt.

like:

    protected array $configurationToUseInTestInstance = [
        'EXTENSIONS' => [
            'your_ext' => [
                'someSetting' => 1,
            ],
        ],
    ];

All other values expected to present inside of $GLOBALS['TYPO3_CONF_VARS']['EXTENSIONS'] are gone the core extensions loaded in base setup class as well.

Specify some data of the environment

• TYPO3 testing framework version: 9.2.0
• TYPO3 version: 13.4.17
• TYPO3 installation type: composer
• PHP version: 8.2