Odtnhj

I have a method I need to Unittest and I am stuck with mocking part of it.

private async void LoginCommandAsync()
 

 .....

 CancellationToken ct;
 var result = await ClientAuthorizationService.CurrentClient.InvokeApiAsync(Constants.ApiConstants.AzureAuthMeData,
 null, HttpMethod.Get, null, ct);

 ....
 

I tried to mock the Microsoft.WindowsAzure.MobileServices.MobileServiceClient using Moq. Unfortunatly I always get a System.InvalidCastException in the last code line

 var currentClient = new Mock<IMobileServiceClient>(MockBehavior.Loose);

 currentClient.Setup(x => x.InvokeApiAsync(Constants.ApiConstants.AzureAuthMeData,
 null, HttpMethod.Get, null, ct)).Returns(Task.FromResult(token));

 var disposableCurrentClient = currentClient.As<IDisposable>();

 ClientAuthorizationService.CurrentClient = (MobileServiceClient)disposableCurrentClient.Object;

MobileServiceClient inherits from IMobileServiceClient, IDisposable but no matter how I try to use/assign the mocked object... it does not work.

public class ClientAuthorizationService : IClientAuthorizationService

 public MobileServiceClient CurrentClient get; set; 
 public ClientAuthorizationService()
 
 CurrentClient = new MobileServiceClient(Constants.ApiConstants.ApplicationUrl);
 
 

Change ClientAuthorizationService.CurrentClient member/property from MobileServiceClient to IMobileServiceClient

public interface IClientAuthorizationService 
 IMobileServiceClient CurrentClient get; set; 


public class ClientAuthorizationService : IClientAuthorizationService 

 public ClientAuthorizationService() 
 CurrentClient = new MobileServiceClient(Constants.ApiConstants.ApplicationUrl);
 

 public IMobileServiceClient CurrentClient get; set; 
 

This will allow for a mock of the client to be assigned when testing as ClientAuthorizationService is now dependent on abstractions and not implementation concerns.

//....

var clientAuthorizationService = new Mock<IClientAuthorizationService>();

var currentClient = new Mock<IMobileServiceClient>();

currentClient
 .Setup(_ => _.InvokeApiAsync(It.IsAny<string>(), null, HttpMethod.Get, null, It.IsAny<CancellationToken>()))
 .ReturnsAsync(token);

clientAuthorizationService
 .Setup(_ => _.CurrentClient)
 .Returns(currentClient.Object);

//.....

Also it is advised not to use async void except for event handlers

So the code under test needs to be updated accordingly.

private async Task LoginCommandAsync() 

 //.....

 CancellationToken ct;
 var result = await ClientAuthorizationService.CurrentClient.InvokeApiAsync(Constants.ApiConstants.AzureAuthMeData,
 null, HttpMethod.Get, null, ct);

 //....