13 files declare their use of MigrateTestCase in Drupal 8

Drupal6SqlBaseTest.php in core/modules/migrate_drupal/tests/src/Unit/source/d6/Drupal6SqlBaseTest.php

Contains \Drupal\Tests\migrate_drupal\Unit\source\d6\Drupal6SqlBaseTest.

DrupalSqlBaseTest.php in core/modules/migrate_drupal/tests/src/Unit/source/DrupalSqlBaseTest.php

FieldInstanceSettingsTest.php in core/modules/field/tests/src/Unit/Plugin/migrate/process/d7/FieldInstanceSettingsTest.php

FieldSettingsTest.php in core/modules/field/tests/src/Unit/Plugin/migrate/process/d7/FieldSettingsTest.php

FileUriTest.php in core/modules/file/tests/src/Unit/Plugin/migrate/process/d6/FileUriTest.php

FilterSettingsTest.php in core/modules/filter/tests/src/Kernel/Plugin/migrate/process/FilterSettingsTest.php

IteratorTest.php in core/modules/migrate/tests/src/Unit/process/IteratorTest.php

MigrateProcessTestCase.php in core/modules/migrate/tests/src/Unit/process/MigrateProcessTestCase.php

PerComponentEntityDisplayTest.php in core/modules/migrate/tests/src/Unit/destination/PerComponentEntityDisplayTest.php

Contains \Drupal\Tests\migrate\Unit\destination\PerComponentEntityDisplayTest.

PerComponentEntityFormDisplayTest.php in core/modules/migrate/tests/src/Unit/destination/PerComponentEntityFormDisplayTest.php

Contains \Drupal\Tests\migrate\Unit\destination\PerComponentEntityFormDisplayTest.

ProcessFieldTest.php in core/modules/field/tests/src/Unit/Plugin/migrate/process/ProcessFieldTest.php

SubProcessTest.php in core/modules/migrate/tests/src/Unit/process/SubProcessTest.php

UrlEncodeTest.php in core/modules/migrate/tests/src/Unit/process/UrlEncodeTest.php