7 files declare their use of PageCacheTagsTestBase

EntityCacheTagsTestBase.php in core/modules/system/tests/src/Functional/Entity/EntityCacheTagsTestBase.php
MenuCacheTagsTest.php in core/modules/menu_ui/tests/src/Functional/MenuCacheTagsTest.php
NavigationShortcutsBlockTest.php in core/modules/navigation/tests/src/Functional/NavigationShortcutsBlockTest.php
NavigationUserBlockTest.php in core/modules/navigation/tests/src/Functional/NavigationUserBlockTest.php
ShortcutsNavigationBlockTest.php in core/modules/navigation/tests/src/Functional/ShortcutsNavigationBlockTest.php
TourCacheTagsTest.php in core/modules/tour/tests/src/Functional/TourCacheTagsTest.php
UserNavigationBlockTest.php in core/modules/navigation/tests/src/Functional/UserNavigationBlockTest.php

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