18 files declare their use of EntityTestMulRev in Drupal 9

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

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

ContentTranslationFieldSyncRevisionTest.php in core/modules/content_translation/tests/src/Kernel/ContentTranslationFieldSyncRevisionTest.php

EntityConverterLatestRevisionTest.php in core/tests/Drupal/KernelTests/Core/ParamConverter/EntityConverterLatestRevisionTest.php

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

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

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

EntityResolverTest.php in core/modules/serialization/tests/src/Kernel/EntityResolverTest.php

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

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

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

EntitySerializationTest.php in core/modules/serialization/tests/src/Kernel/EntitySerializationTest.php

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

EntityViewsDataTest.php in core/modules/views/tests/src/Unit/EntityViewsDataTest.php

Contains \Drupal\Tests\views\Unit\EntityViewsDataTest.

entity_schema_test.module in core/modules/system/tests/modules/entity_schema_test/entity_schema_test.module

Test module for the entity API providing a bundle field.

FieldItemSerializationTest.php in core/modules/serialization/tests/src/Kernel/FieldItemSerializationTest.php

FieldItemTest.php in core/tests/Drupal/KernelTests/Core/Field/FieldItemTest.php

FieldMissingTypeTest.php in core/tests/Drupal/KernelTests/Core/Field/FieldMissingTypeTest.php