TYPO3 v11: Unit testing fails with Nimut/testing-framework

$ .Build/bin/phpunit --colors=never -c phpunit.xml
PHPUnit 9.6.29 by Sebastian Bergmann and contributors.
 
Error in bootstrap script: Symfony\Component\Finder\Exception\DirectoryNotFoundException:
The "web/typo3conf/ext/iw_social/.Build/web/typo3/sysext/*/" directory does not exist.
#0 web/typo3conf/ext/iw_social/.Build/vendor/typo3/cms-core/Classes/Package/PackageManager.php(350): Symfony\Component\Finder\Finder->in()
#1 web/typo3conf/ext/iw_social/.Build/vendor/typo3/cms-core/Classes/Package/PackageManager.php(255): TYPO3\CMS\Core\Package\PackageManager->scanPackagePathsForExtensions()
#2 web/typo3conf/ext/iw_social/.Build/vendor/typo3/cms-core/Classes/Package/UnitTestPackageManager.php(31): TYPO3\CMS\Core\Package\PackageManager->scanAvailablePackages()
#3 web/typo3conf/ext/iw_social/.Build/vendor/typo3/cms-core/Classes/Core/Bootstrap.php(255): TYPO3\CMS\Core\Package\UnitTestPackageManager->initialize()
#4 web/typo3conf/ext/iw_social/.Build/vendor/nimut/testing-framework/src/TestingFramework/Bootstrap/AbstractBootstrap.php(247): TYPO3\CMS\Core\Core\Bootstrap::createPackageManager()
#5 web/typo3conf/ext/iw_social/.Build/vendor/nimut/testing-framework/src/TestingFramework/Bootstrap/AbstractBootstrap.php(81): Nimut\TestingFramework\Bootstrap\AbstractBootstrap->initializePackageManager()
#6 web/typo3conf/ext/iw_social/.Build/vendor/nimut/testing-framework/res/Configuration/UnitTestsBootstrap.php(35): Nimut\TestingFramework\Bootstrap\AbstractBootstrap->bootstrapUnitTestSystem()
#7 web/typo3conf/ext/iw_social/.Build/vendor/nimut/testing-framework/res/Configuration/UnitTestsBootstrap.php(36): PHPUnit\Util\FileLoader::{closure}()
#8 web/typo3conf/ext/iw_social/.Build/vendor/phpunit/phpunit/src/Util/FileLoader.php(66): include_once('...')
#9 web/typo3conf/ext/iw_social/.Build/vendor/phpunit/phpunit/src/Util/FileLoader.php(49): PHPUnit\Util\FileLoader::load()
#10 web/typo3conf/ext/iw_social/.Build/vendor/phpunit/phpunit/src/TextUI/Command.php(567): PHPUnit\Util\FileLoader::checkAndLoad()
#11 web/typo3conf/ext/iw_social/.Build/vendor/phpunit/phpunit/src/TextUI/Command.php(347): PHPUnit\TextUI\Command->handleBootstrap()
#12 web/typo3conf/ext/iw_social/.Build/vendor/phpunit/phpunit/src/TextUI/Command.php(114): PHPUnit\TextUI\Command->handleArguments()
#13 web/typo3conf/ext/iw_social/.Build/vendor/phpunit/phpunit/src/TextUI/Command.php(99): PHPUnit\TextUI\Command->run()
#14 web/typo3conf/ext/iw_social/.Build/vendor/phpunit/phpunit/phpunit(107): PHPUnit\TextUI\Command::main()
#15 web/typo3conf/ext/iw_social/.Build/bin/phpunit(122): include('...')
#16 {main}