방법1 public class MailServiceTest { @DisplayName("메일 전송 테스트") @Test void sendMail() { // given MailSendClient mailSendClient = Mockito.mock(MailSendClient.class); final MailSendHistoryRepository mailSendHistoryRepository = Mockito.mock(MailSendHistoryRepository.class); final MailService mailService = new MailService(mailSendClient, mailSendHistoryRepository); Mockito.when(mailSendClient.sendEmail..