13 files declare their use of TaxonomyTestTrait in Drupal 8

CommentEntityTest.php in core/modules/comment/tests/src/Functional/CommentEntityTest.php

PrepareUninstallTest.php in core/modules/system/tests/src/Functional/Module/PrepareUninstallTest.php

TaxonomyFieldTidTest.php in core/modules/taxonomy/tests/src/Kernel/Views/TaxonomyFieldTidTest.php

TaxonomyFieldVidTest.php in core/modules/taxonomy/tests/src/Kernel/Views/TaxonomyFieldVidTest.php

TaxonomyGlossaryTest.php in core/modules/views/tests/src/Functional/TaxonomyGlossaryTest.php

TaxonomyLegacyTest.php in core/modules/taxonomy/tests/src/Kernel/TaxonomyLegacyTest.php

TaxonomyQueryAlterTest.php in core/modules/taxonomy/tests/src/Kernel/TaxonomyQueryAlterTest.php

TaxonomyTestBase.php in core/modules/taxonomy/src/Tests/TaxonomyTestBase.php

TaxonomyTestBase.php in core/modules/taxonomy/tests/src/Functional/TaxonomyTestBase.php

TaxonomyTestTrait.php in core/modules/taxonomy/tests/src/Functional/TaxonomyTestTrait.php

TermEntityQueryTest.php in core/modules/taxonomy/tests/src/Kernel/TermEntityQueryTest.php

TermKernelTest.php in core/modules/taxonomy/tests/src/Kernel/TermKernelTest.php

VocabularyCrudTest.php in core/modules/taxonomy/tests/src/Kernel/VocabularyCrudTest.php