public async void ReturnTrue()
            {
                var sut = new ExternalSimCardsProviderService(options, httpClient);

                var actual = await sut.PostOrder(expectedOrder);

                actual.Should().BeTrue();
            }
            public async void CallExternalService()
            {
                var sut = new ExternalSimCardsProviderService(options, httpClient);

                await sut.PostOrder(expectedOrder);

                handlerMock.VerifyAll();
            }
            public async void ReturnFalseWhenResponseStatusCodeIsNotOK()
            {
                var handlerWithErrorMock = new Mock <DelegatingHandler>();

                handlerWithErrorMock.Protected()
                .Setup <Task <HttpResponseMessage> >("SendAsync",
                                                     ItExpr.Is <HttpRequestMessage>(
                                                         x => x.RequestUri == expectedUrl),
                                                     ItExpr.IsAny <CancellationToken>())
                .Returns(Task.FromResult(new HttpResponseMessage(HttpStatusCode.InternalServerError)
                {
                    Content = new StringContent(JsonSerializer.Serialize(expectedOrder))
                }
                                         ));
                var httpClientWithError = new HttpClient(handlerWithErrorMock.Object);

                var sut = new ExternalSimCardsProviderService(options, httpClientWithError);

                var actual = await sut.PostOrder(expectedOrder);

                actual.Should().BeFalse();
            }