17 files declare their use of Container

BlockPageVariantTest.php in core/modules/block/tests/src/Unit/Plugin/DisplayVariant/BlockPageVariantTest.php
CacheTest.php in core/tests/Drupal/Tests/Core/Cache/CacheTest.php
ContainerTest.php in core/tests/Drupal/Tests/Core/DependencyInjection/ContainerTest.php
DefaultMenuLinkTreeManipulatorsTest.php in core/tests/Drupal/Tests/Core/Menu/DefaultMenuLinkTreeManipulatorsTest.php
EntityAccessCheckTest.php in core/tests/Drupal/Tests/Core/Entity/EntityAccessCheckTest.php
EntityConditionTest.php in core/modules/jsonapi/tests/src/Unit/Query/EntityConditionTest.php
EntityCreateAccessCheckTest.php in core/tests/Drupal/Tests/Core/Entity/EntityCreateAccessCheckTest.php
EntityFormDisplayAccessControlHandlerTest.php in core/tests/Drupal/Tests/Core/Entity/Access/EntityFormDisplayAccessControlHandlerTest.php
ErrorContainer.php in core/tests/Drupal/FunctionalTests/Bootstrap/ErrorContainer.php
ExceptionContainer.php in core/tests/Drupal/FunctionalTests/Bootstrap/ExceptionContainer.php
FieldStorageConfigAccessControlHandlerTest.php in core/modules/field/tests/src/Unit/FieldStorageConfigAccessControlHandlerTest.php
LocalActionManagerTest.php in core/tests/Drupal/Tests/Core/Menu/LocalActionManagerTest.php
OffsetPageTest.php in core/modules/jsonapi/tests/src/Unit/Query/OffsetPageTest.php
RoleAccessCheckTest.php in core/tests/Drupal/Tests/Core/Route/RoleAccessCheckTest.php
SortTest.php in core/modules/jsonapi/tests/src/Unit/Query/SortTest.php
TestDiscoveryTest.php in core/tests/Drupal/Tests/Core/Test/TestDiscoveryTest.php
UserAccessControlHandlerTest.php in core/modules/user/tests/src/Unit/UserAccessControlHandlerTest.php

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