public async Task GetExamplesAsync_ExamplesDoNotExist_ReturnsNotFound(
            [Frozen] Mock <IExampleService> exampleServiceMock,
            ExampleController sut)
        {
            exampleServiceMock.Setup(x => x.GetExamplesAsync()).Returns(Task.FromResult <IEnumerable <Example> >(null));

            var result = await sut.GetExamplesAsync();

            var notfoundResult = result.Result as NotFoundResult;

            notfoundResult.StatusCode.Should().Be(StatusCodes.Status404NotFound);
        }
        public async Task GetExamplesAsync_ExamplesExist_ReturnsOkExamples(
            [Frozen] Mock <IExampleService> exampleServiceMock,
            IEnumerable <Example> examples,
            ExampleController sut)
        {
            exampleServiceMock.Setup(x => x.GetExamplesAsync()).Returns(Task.FromResult(examples));

            var result = await sut.GetExamplesAsync();

            var okObjectResult = result.Result as OkObjectResult;

            okObjectResult.StatusCode.Should().Be(StatusCodes.Status200OK);
            okObjectResult.Value.Should().BeEquivalentTo(examples);
        }