public async Task TestStartCreatesNewResponseWhenNoCurrentResponseThenRedirects()
{
// Arrange
var clientStorage = Substitute.For <IClientSideStorageService>();
var dateTime = Substitute.For <IDateTimeService>();
var repo = Substitute.For <ISurveyResponseRepository>();
repo.Create().Returns(SurveyResponse.CreateNew(FakeNow));
var controller = new SurveyController(clientStorage, dateTime, null, null, repo);
// Act
var result = await controller.Start();
// Assert
await repo.Received().Create();
Assert.IsType <RedirectToActionResult>(result);
}