According to Nanahira, テストロイヤー "Testroyer" is originated from the word "Destroyer". Therefore we should consider it as a loan (an English) word. It should be "Testroyer" regardless of how to pronounce in this case.RankingCriteria wrote:
Songs with Japanese titles must use the Modified Hepburn method of romanisation in the "Romanised Title" field. As a non-unicode field, long vowels such as "おう" and "うう" should be romanised into "ou" and "uu" to avoid macrons. Loan words should be expressed using romanisation from the original language.
In short, there is no need type a hyphen, definitely.