public void ModifyHeaderValueIfCustomHeaderDoesNotExistInResponse()
{
var fakeInnerHandler = new FakeInnerHttpMessageHandler { Message = this.fakeResponseWithoutHeader };
var messageInvoker =
new HttpMessageInvoker(
new FakeCustomHeaderHttpMessageHandler(FakeHeaderName) { InnerHandler = fakeInnerHandler });
var requestMessage = new HttpRequestMessage(HttpMethod.Get, "http://localhost/Fake");
var responseMessage = messageInvoker.SendAsync(requestMessage, this.cancellationToken).Result;
Assert.True(responseMessage.Headers.Contains(FakeHeaderName));
Assert.Equal(ModifiedHeaderValue, responseMessage.Headers.GetValues(FakeHeaderName).First());
}