public async Task ActiveBuses_GetCountByInvalidNumber_ReturnNull()
{
//Arrange
int routeNumber = -1;
var mock = new Mock <IBusInformationService>();
mock.Setup(x => x.GetActiveBusesCount(routeNumber, 't')).ReturnsAsync((int?)null);
var controller = new BusController(mock.Object);
//Act
var result = await controller.ActiveBuses(routeNumber);
//Assert
Assert.IsNull(result.Model);
}