public async Task Update_ReturnsGuest()
{
// arrange
var guest = new Guest {
guestId = 123, name = "Guest1", email = "*****@*****.**", isGoing = true, eventId = 1
};
_guestQueryMock.Setup(x => x.Update(guest))
.Returns(Task.Factory.StartNew(() => guest));
// act
var task = await _sut.Update(guest);
// assert
Assert.IsType <OkObjectResult>(task);
var result = task as OkObjectResult;
var guestResult = result.Value as bool?;
Assert.True(guestResult);
}