public async Task DeleteAsync_AppointmentIsDeleted_ReturnsNoContent()
{
// Arrange
var appointment = _fixture.Create <Appointment>();
int id = 10;
_appointmentService
.Setup(a => a.DeleteAppointmentAsync(id))
.ReturnsAsync(appointment);
// Act
var actual = await _appointmentsController.DeleteAsync(id);
// Assert
_appointmentService.Verify(a => a.DeleteAppointmentAsync(id), Times.Once);
Assert.IsType <NoContentResult>(actual);
}