11 files declare their use of EntityTestBundle in Drupal 9

BundlePermissionHandlerTraitTest.php in core/tests/Drupal/KernelTests/Core/Entity/BundlePermissionHandlerTraitTest.php

DeleteMultipleFormTest.php in core/tests/Drupal/FunctionalTests/Entity/DeleteMultipleFormTest.php

EntityAddUITest.php in core/modules/system/tests/src/Functional/Entity/EntityAddUITest.php

EntityBundleConditionTest.php in core/tests/Drupal/KernelTests/Core/Entity/EntityBundleConditionTest.php

EntityBundleListCacheTest.php in core/tests/Drupal/FunctionalTests/Entity/EntityBundleListCacheTest.php

EntityTestBundleResourceTestBase.php in core/modules/system/tests/modules/entity_test/tests/src/Functional/Rest/EntityTestBundleResourceTestBase.php

EntityTestPermissions.php in core/modules/system/tests/modules/entity_test/src/EntityTestPermissions.php

EntityTypeInfoTest.php in core/modules/content_moderation/tests/src/Kernel/EntityTypeInfoTest.php

FieldResolverTest.php in core/modules/jsonapi/tests/src/Kernel/Context/FieldResolverTest.php

InternalEntitiesTest.php in core/modules/jsonapi/tests/src/Functional/InternalEntitiesTest.php

MediaLibraryAccessTest.php in core/modules/media_library/tests/src/Kernel/MediaLibraryAccessTest.php