Moq sample for testing MonitorService.

MonitorServiceTest.cs

[TestClass]
public class MonitorServiceTest
{
     private MonitorService _monitorService; // System under test (SUT)
     private Mock<MailService> _mockMailService; // Test Double
     private Mock<IOhterService> _mockOtherService; // Test Double
     private IOptions<ConfigModel> _configModelOptions; // Configuration
     
     [TestInitialize] // Setup
     public void Initialize()
     {
          _configModelOptions = Options.Create(new ConfigModel
          {
              APIBaseInfo = new APIBaseInfo
              {
                  MailReceiverUri = "/v1/mail/service/receiver/{roles}",                  
              }
          });

          _mockMailService = new Mock<MailService>(MockBehavior.Loose, new object[] { _configModelOptions, null}){};
          _mockOtherService = new Mock<IOtherService>(MockBehavior.Loose);

          _monitorService = new MonitorService(_configModelOptions, _mockMailService.Object, _mockOtherService.Object);
      }
      
      [TestMethod]
      public void Test_System_Tracking_Heart_Beat_Send_Mail_To_Group1_Should_Return_Sucesss()
      {
           // arrange
            var role = "Group1";
            var heartbeat = "{\"SystemName\":\"PaymentAPI\", \"Status\":\"Health\"}";
            
            // override method that we just want to print out the information but not real drop to mail server
            _mockMailService.Setup(m => m.SendMailNotify(It.IsAny<List<Receiver>>(), It.IsAny<string>(), It.IsAny<string>(), It.IsAny<string[]>(), It.IsAny<string>())).Callback((IEnumerable<Receiver> receiverList, string subject, string content, string[] filePaths, string tag) =>
            {
                // write to debug output windows
                Debug.WriteLine($"{subject}, {content}.");
            });
            
            // we will retrieve the real role(s) data back that help us for saving preparing diverse mock data in the testing target
            _mockMailService.Setup(m => m.GetReceivers(role)).CallBase();
            
            // execute
            var result = _monitorService_monitorService.TrackHeartBeat(heartbeat);
            
            // verify
             Assert.AreEqual("Success", result.Status);
      }
     
      [TestMethod]
      public void Test_System_Tracking_Heart_Beat_Down_Send_Mail_To_Admin_Should_Return_Sucesss()
      {
           // arrange
            var role = "Admin";
            var heartbeat = "{\"SystemName\":\"PaymentAPI\", \"Status\":\"Down\"}";
            
            // override method that we just want to print out the information but not real drop to mail server
            _mockMailService.Setup(m => m.SendMailNotify(It.IsAny<List<Receiver>>(), It.IsAny<string>(), It.IsAny<string>(), It.IsAny<string[]>(), It.IsAny<string>())).Callback((IEnumerable<Receiver> receiverList, string subject, string content, string[] filePaths, string tag) =>
            {
                // write to debug output windows
                Debug.WriteLine($"{subject}, {content}.");
            });
            
            // we will retrieve the real role(s) data back that help us for saving preparing diverse mock data in the testing target
            _mockMailService.Setup(m => m.GetReceivers(role)).CallBase();
            
            // execute
            var result = _monitorService_monitorService.TrackHeartBeatDown(heartbeat);
            
            // verify
             Assert.AreEqual("Success", result.Status);
      }
      
}