How to unit test a method with HttpWebRequest/Response dependencies - unit-testing

Question

Been trying to unit test this method but can't figure out how to do it.
public bool ValidateCaptcha(string captchaResponse, string captchaChallenge,
string hostip)
{
var strPrivateKey = _secConfiguration.CaptchaPrivateKey;
var strParameters = "verify?privatekey=" + strPrivateKey +
"&remoteip=" + hostip +
"&challenge=" + captchaChallenge+
"&response=" + captchaResponse;
var url = CaptchaUrl + strParameters;
var request = CreateHttpWebRequest(url);
request.Proxy.Credentials = CredentialCache.DefaultCredentials;
request.Method = "POST";
request.ContentType = "text/html";
request.ContentLength = 0;
var response = GetHttpWebResponse(request);
var writer = response.GetResponseStream();
var reader = new StreamReader(writer);
var responseFromServer = reader.ReadToEnd();
var serverResponse = responseFromServer.Split('\n');
return serverResponse[0] == "true";
}
private HttpWebResponse GetHttpWebResponse(HttpWebRequest request)
{
return (HttpWebResponse) request.GetResponse();
}
private HttpWebRequest CreateHttpWebRequest(string url)
{
return (HttpWebRequest) WebRequest.Create(url);
}
I had planned to moq the dependencies and have a couple of wrap classes
public class WrapHttpWebRequest : IHttpWebRequest
{
private readonly HttpWebRequest _request;
public WrapHttpWebRequest(HttpWebRequest request)
{
_request = request;
}
public string Method
{
get { return _request.Method; }
set { _request.Method = value; }
}
public IHttpWebResponse GetResponse()
{
return new WrapHttpWebResponse((HttpWebResponse)_request.GetResponse());
}
}
and
public class WrapHttpWebResponse : IHttpWebResponse
{
private WebResponse _response;
public WrapHttpWebResponse(HttpWebResponse response)
{
_response = response;
}
public void Dispose()
{
Dispose(true);
GC.SuppressFinalize(this);
}
private void Dispose(bool disposing)
{
if (disposing)
{
if (_response != null)
{
((IDisposable)_response).Dispose();
_response = null;
}
}
}
public Stream GetResponseStream()
{
return _response.GetResponseStream();
}
}
But can't find a way to inject them. Any ideas how can I do this? Thanks.

Answer 1

You could create testable version of your class under test.
Make the method virtual and override it in the testable version.
protected virtual HttpWebRequest CreateHttpWebRequest(string url)
{
return (HttpWebRequest)WebRequest.Create(url);
}
public class TesableClassUnderTest : ClassUnderTest
{
public HttpWebRequest HttpWebRequestFake { get; set; }
protected override HttpWebRequest CreateHttpWebRequest(string url)
{
if (HttpWebRequestFake != null)
return HttpWebRequestFake;
return base.CreateHttpWebRequest(url);
}
}
Then in test set the fake object to your own value:
[TestMethod]
public void test()
{
TesableClassUnderTest cut = new TesableClassUnderTest();
cut.HttpWebRequestFake = CreateFakeHttpWebRequest();
cut.ValidateCaptcha(...)
Assert...
}