There were 22 errors:

1) ArticlePlaceholder\Tests\SearchHookHandlerTest::testNewFromGlobalState
Error: Class "Wikibase\Client\WikibaseClient" not found

/workspace/src/extensions/ArticlePlaceholder/includes/SearchHookHandler.php:54
/workspace/src/vendor/wikimedia/testing-access-wrapper/src/TestingAccessWrapper.php:114
/workspace/src/extensions/ArticlePlaceholder/tests/phpunit/includes/SearchHookHandlerTest.php:134
=== Logs generated by test case
[objectcache] [debug] MainWANObjectCache using store {class} {"class":"Wikimedia\\ObjectCache\\HashBagOStuff"}
[localisation] [debug] LocalisationCache using store LCStoreNull []
===

2) ArticlePlaceholder\Tests\SearchHookHandlerTest::testAddToSearch with data set #0 ('get term, check if entity wit...turned', 'Unicorn', '>Q7246 en label</a>: Q7246 en...</div>')
Error: Class "Wikibase\Lib\Interactors\MatchingTermsLookupSearchInteractor" not found

/workspace/src/extensions/ArticlePlaceholder/tests/phpunit/includes/SearchHookHandlerTest.php:90
/workspace/src/extensions/ArticlePlaceholder/tests/phpunit/includes/SearchHookHandlerTest.php:119
/workspace/src/extensions/ArticlePlaceholder/tests/phpunit/includes/SearchHookHandlerTest.php:163
=== Logs generated by test case
[objectcache] [debug] MainWANObjectCache using store {class} {"class":"Wikimedia\\ObjectCache\\HashBagOStuff"}
[localisation] [debug] LocalisationCache using store LCStoreNull []
===
...