public async Task DeleteShouldReturnOkResultWithModelId()
        {
            // Arrange
            var model = new Flight();

            var fakeSql = Substitute.For<IDatabase>();
            fakeSql.DeleteAsync(model).ReturnsForAnyArgs(Task.FromResult(true));

            var controller = new FlightsController(fakeSql);

            // Act
            var result = await controller.Delete(1);

            // Assert
            var viewResult = Assert.IsType<OkNegotiatedContentResult<int>>(result);
            Assert.Equal(viewResult.Content, 1);
        }
        public async Task DeleteShouldReturnBadRequestResultWhenResultFalse()
        {
            // Arrange
            var model = new Flight();

            var fakeSql = Substitute.For<IDatabase>();
            fakeSql.DeleteAsync(model).ReturnsForAnyArgs(Task.FromResult(false));

            var controller = new FlightsController(fakeSql);

            // Act
            var result = await controller.Delete(1);

            // Assert
            var viewResult = Assert.IsType<BadRequestResult>(result);
            Assert.NotNull(viewResult);
        }