public void GetCountOfUsersShouldWorkCorrectly() { var userChars = new List <UserCharacteristic>(); var mockUserChar = new Mock <IDeletableEntityRepository <UserCharacteristic> >(); mockUserChar.Setup(x => x.All()).Returns(userChars.AsQueryable()); mockUserChar.Setup(x => x.AddAsync(It.IsAny <UserCharacteristic>())).Callback((UserCharacteristic uc) => userChars.Add(uc)); var service = new AdminsService(null, null, null, mockUserChar.Object, null); var user = new UserCharacteristic { Id = "1", }; userChars.Add(user); var expectedResult = 1; var result = service.GetCountOfUsers(); Assert.Equal(expectedResult, result); }