public async Task AddFollowerWithId_Valid_Test() { // Arrange _cityParticipantsService .Setup(c => c.AddFollowerAsync(It.IsAny <int>(), It.IsAny <string>())) .ReturnsAsync(new CityMembersDTO()); _logger .Setup(l => l.LogInformation(It.IsAny <string>())); CitiesController citycon = CreateCityController; // Act var result = await citycon.AddFollowerWithId(GetFakeID(), GetStringFakeId()); // Assert Assert.NotNull(result); Assert.IsInstanceOf <OkObjectResult>(result); }