@Test
public void nestedTypesSplit() {

    validator.validateUnion(TestMergedNestedTypesProto.RecordTypeUnion.getDescriptor(), TestSplitNestedTypesProto.RecordTypeUnion.getDescriptor());
    FileDescriptor updatedSplitFile = mutateField("NestedB", "b", TestSplitNestedTypesProto.getDescriptor(),
            field -> field.setType(DescriptorProtos.FieldDescriptorProto.Type.TYPE_BYTES));
    assertInvalid("field type changed", TestUnmergedNestedTypesProto.getDescriptor(), updatedSplitFile);
}