public void GetForecast_WhenCalled_ReturnsOkAndCityForecastDTO()
{
// Arrange
this._externalServiceMock.Setup(svc => svc.GetCityForecast(It.IsAny <string>()))
.Returns(new CityForecastDTO());
CitiesController controller = this.GenerateCitiesController();
// Act
var okResult = controller.GetForecast("x12345");
// Assert
Assert.IsType <OkObjectResult>(okResult.Result);
Assert.IsType <CityForecastDTO>((okResult.Result as OkObjectResult).Value);
}