public void Test_Generate_Success_Tempalate_With_Record_Flag() { //Arrange var mock = new Mock <IRecord>(); mock.Setup(m => m.IsStudentRecord(It.Is <Student>(s => s.Score >= 600))) .Returns(true); var studentMike = new Student { Name = "Mick", EmailAddr = "*****@*****.**", Score = 600 }; var smock = new SendMail(mock.Object); //Action var content = smock.GenderateTemplate(studentMike); //Assert mock.Verify(o => o.IsStudentRecord(studentMike)); Assert.AreEqual("Success", content); }