Problem/Motivation
The property $translationFilesDirectory is defined in two test files and set in
\Drupal\Core\Test\FunctionalTestSetupTrait::prepareEnvironment but it is not used.
\Drupal\TestSite\Commands\TestSiteInstallCommand::$translationFilesDirectory
\Drupal\Tests\BrowserTestBase::$translationFilesDirectory
FunctionalTestSetupTrait::prepareEnvironment() sets $this->translationFilesDirectory. However it's being set to $this->siteDirectory . '/translations' where it should be $this->siteDirectory . '/files/translations'. Also it's not declared in FunctionalTestSetupTrait but instead in BrowserTestBase and TestBase.
History of use
This
)$ git log -StranslationFilesDirectory --oneline
ffdecfadf64 Issue #3274474 by mondrake, longwave, andypost, Spokje, catch, alexpott: Fix 'Access to an undefined property' PHPStan L0 errors
57a7de37983 Issue #3260928 by mondrake, mallezie, neclimdul, mglaman: Move more PHPStan global ignore patterns to baseline
a4f6e550564 Issue #3110862 by longwave, alexpott, catch, Mile23, Lendude, Gábor Hojtsy, Berdir: Remove simpletest module from core
7204a00a1be Issue #2870009 by Lendude, dawehner: Update: Convert system functional tests to phpunit
9d5b5a5363d Issue #2469721 by larowlan, alexpott, dawehner, jibran: Add functionality to store browser output to BrowserTestBase
300f14e8603 Issue #2232861 by grom358, daffie, alexpott, larowlan, pfrenssen, hussainweb, pcambra, jibran, phenaproxima, moshe weitzman, nick_schuch: Create BrowserTestBase for web-testing on top of Mink
b45af923af0 Issue #2382195 by tibbsa, subhojit777, tadityar, cilefen, Mile23: Clean-up simpletest module test members - ensure property definition and use of camelCase naming convention
which was previously translation_files_directory
$ git log -Stranslation_files_directory --oneline
62afe776837 Issue #3097892 by mondrake, longwave, Berdir: Remove all @deprecated code in test base classes
d5821399fc9 Issue #2304461 by dawehner, neclimdul, naveenvalecha, jibran, tim.plunkett, phenaproxima, Xano, hussainweb, sun, hitesh-jain, amateescu, alexpott, daffie, Mile23, Wim Leers, larowlan: KernelTestBaseTNG™
b45af923af0 Issue #2382195 by tibbsa, subhojit777, tadityar, cilefen, Mile23: Clean-up simpletest module test members - ensure property definition and use of camelCase naming convention
db460fe78bf Issue #2171683 by sun, alexpott, tstoeckler, larowlan: Remove all Simpletest overrides and rely on native multi-site functionality instead.
ec06f877a47 Revert "Issue #2171683 by sun, tstoeckler, larowlan: Remove all Simpletest overrides and rely on native multi-site functionality instead."
91db25eba49 Issue #2171683 by sun, tstoeckler, larowlan: Remove all Simpletest overrides and rely on native multi-site functionality instead.
bcc57baf0b8 Issue #1881582 by sun: Change configuration overrides to use $config instead of $conf.
2a993a893b7 Issue #2022549 by valdo, ParisLiakos, YesCT: Regression: No interface translation in the first installer steps.
8fadfdfb3c4 Issue #1961938 by chx, alexpott, YesCT, xjm, attheshow, dawehner: Test the interactive installer.
d2d67960620 Issue #1791920 by c960657: Fixed Create new translations:// directory for tests.Proposed resolution
Either remove the member variable completely or fix it and use it in various install tests. Alternatively it could also be moved to InstallerTestBase.
Remaining tasks
Research the history of the property to determine what to do.