7 files declare their use of AssertHelperTrait in Zircon Profile 8

AssertHelperTraitTest.php in core/modules/simpletest/tests/src/Unit/AssertHelperTraitTest.php

Contains \Drupal\Tests\simpletest\Unit\AssertHelperTraitTest.

BookUninstallValidatorTest.php in core/modules/book/tests/src/Unit/BookUninstallValidatorTest.php

Contains \Drupal\Tests\book\Unit\BookUninstallValidatorTest.

FieldUninstallValidatorTest.php in core/modules/field/tests/src/Unit/FieldUninstallValidatorTest.php

Contains \Drupal\Tests\field\Unit\FieldUninstallValidatorTest.

FilterUninstallValidatorTest.php in core/modules/filter/tests/src/Unit/FilterUninstallValidatorTest.php

Contains \Drupal\Tests\filter\Unit\FilterUninstallValidatorTest.

ForumUninstallValidatorTest.php in core/modules/forum/tests/src/Unit/ForumUninstallValidatorTest.php

Contains \Drupal\Tests\forum\Unit\ForumUninstallValidatorTest.

KernelTestBase.php in core/tests/Drupal/KernelTests/KernelTestBase.php

Contains \Drupal\KernelTests\KernelTestBase.

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

Contains \Drupal\Tests\Core\Extension\RequiredModuleUninstallValidatorTest.