12 files declare their use of FileSystemModuleDiscoveryDataProviderTrait in Drupal 9

DefaultConfigTest.php in core/tests/Drupal/KernelTests/Config/DefaultConfigTest.php

DestinationCategoryTest.php in core/modules/migrate_drupal/tests/src/Kernel/Plugin/migrate/DestinationCategoryTest.php

MigrateDrupal6AuditIdsTest.php in core/modules/migrate_drupal/tests/src/Kernel/d6/MigrateDrupal6AuditIdsTest.php

MigrateDrupal7AuditIdsTest.php in core/modules/migrate_drupal/tests/src/Kernel/d7/MigrateDrupal7AuditIdsTest.php

MigrationLabelExistTest.php in core/modules/migrate_drupal_ui/tests/src/Kernel/MigrationLabelExistTest.php

MigrationProcessTest.php in core/modules/migrate_drupal/tests/src/Kernel/d6/MigrationProcessTest.php

MigrationProcessTest.php in core/modules/migrate_drupal/tests/src/Kernel/d7/MigrationProcessTest.php

MigrationProvidersExistTest.php in core/modules/migrate/tests/src/Kernel/Plugin/MigrationProvidersExistTest.php

ModuleConfigureRouteTest.php in core/tests/Drupal/KernelTests/Core/Extension/ModuleConfigureRouteTest.php

ModuleInfoTest.php in core/tests/Drupal/Tests/Core/Extension/ModuleInfoTest.php

StateFileExists.php in core/modules/migrate_drupal/tests/src/Kernel/StateFileExists.php

ValidateMigrationStateTestTrait.php in core/modules/migrate_drupal/tests/src/Traits/ValidateMigrationStateTestTrait.php