### Question:
MailContentBuilderService { public String build(final String templateNameOrUrl, final Map<String, String> details) { return templateEngine.process(templateNameOrUrl, buildContext(details)); } @Autowired  MailContentBuilderService(TemplateEngine templateEngine); String build(final String templateNameOrUrl, final Map<String, String> details); String buildPlainTextMail(String mailBody, final Map<String, Object> details); String getRemoteMailContent(String templateUrl);  }### Answer:
@Test public void buildTest() throws Exception { Map<String, String> values = Maps.newHashMap(); values.put("key", "value"); Whitebox.invokeMethod(mailContentService, "buildContext", values); }