8 files declare their use of MigrateProcessTestCase in Drupal 10

BlockVisibilityTest.php in core/modules/block/tests/src/Unit/Plugin/migrate/process/BlockVisibilityTest.php

ConvertTokensTest.php in core/modules/user/tests/src/Unit/Plugin/migrate/process/ConvertTokensTest.php

FieldTypeDefaultsTest.php in core/modules/field/tests/src/Unit/Plugin/migrate/process/d6/FieldTypeDefaultsTest.php

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

LanguageDomainsTest.php in core/modules/language/tests/src/Unit/process/LanguageDomainsTest.php

LanguageNegotiationTest.php in core/modules/language/tests/src/Unit/process/LanguageNegotiationTest.php

LanguageTypesTest.php in core/modules/language/tests/src/Unit/process/LanguageTypesTest.php

PathSetTranslatedTest.php in core/modules/path/tests/src/Unit/migrate/process/PathSetTranslatedTest.php