### Question:
App { public String getGreeting() { return "[SMTP Client] Welcome to SMTP Client."; }  String getGreeting(); Properties getEmailProperties(String propertiesPath); String buildPrompt(); String maskPassword(String password); void sendEmail(Properties props); static void main(String[] args);  }### Answer:
@Test public void testAppHasAGreeting() { App classUnderTest = new App(); assertNotNull("app should have a greeting", classUnderTest.getGreeting()); }