public async void AcceptFriendRequestRoute_Test() { // Arrange var user = CreatePerson(); var friend = CreatePerson(); var acceptedFriends = new List <Person>(); _personRepository .Setup(x => x.Single(p => p.Name == user.Name)) .ReturnsAsync(user); _personRepository .Setup(x => x.Single(p => p.Name == friend.Name)) .ReturnsAsync(friend); _personRepository .Setup(x => x.Relate <Person, FriendsWith>( It.IsAny <Expression <Func <Person, bool> > >(), It.IsAny <Expression <Func <Person, bool> > >(), It.IsAny <FriendsWith>())) .ReturnsAsync(true) .Callback <Expression <Func <Person, bool> >, Expression <Func <Person, bool> >, FriendsWith>( (exp1, exp2, requestedFriends) => { acceptedFriends.Add(friend); } ); var personController = new PersonController(_personRepository.Object, _mapper, _emailHelper.Object, _tokenClass.Object); var friendController = new FriendController(_personRepository.Object, _friendRepository.Object, _mapper); // Act var result = await friendController.ConfirmFriendRequest(user.Name, friend.Name); var okResult = result as OkObjectResult; // Assert Assert.True(okResult != null); Assert.Equal(200, okResult.StatusCode); }