public void testUnknownExtensions() throws Exception {
// Make sure fields are properly parsed to the UnknownFieldSet even when
// they are declared as extension numbers.
TestEmptyMessageWithExtensions message =
TestEmptyMessageWithExtensions.parseFrom(allFieldsData);
assertEquals(unknownFields.asMap().size(),
message.getUnknownFields().asMap().size());
assertEquals(allFieldsData, message.toByteString());
}