Sometimes when we write integration tests we need to fake HttpContext to test some functionality proper way.

In one of my projects I needed a possibility to fake some session variables such as userState and maxId.

A project that is tested in this example is an ASP.NET Web API with added support for session but you can use the same approach in any ASP.NET/ MVC project.

Implementation is very simple. First, we need to create FakeHttpContext.

 public HttpContext FakeHttpContext(Dictionary<string, object> sessionVariables,string path)
{
    var httpRequest = new HttpRequest(string.Empty, path, string.Empty);
    var stringWriter = new StringWriter();
    var httpResponce = new HttpResponse(stringWriter);
    var httpContext = new HttpContext(httpRequest, httpResponce);
    httpContext.User = new GenericPrincipal(new GenericIdentity("username"), new string[0]);
    Thread.CurrentPrincipal = new GenericPrincipal(new GenericIdentity("username"), new string[0]);
    var sessionContainer = new HttpSessionStateContainer(
      "id",
      new SessionStateItemCollection(),
      new HttpStaticObjectsCollection(),
      10,
      true,
      HttpCookieMode.AutoDetect,
      SessionStateMode.InProc,
      false);

   foreach (var var in sessionVariables)
   {
      sessionContainer.Add(var.Key, var.Value);
   }

   SessionStateUtility.AddHttpSessionStateToContext(httpContext, sessionContainer);
   return httpContext;
}

After we have FakeHttpContext we can easily use it in any integration tests like this.

 [Test]
public void DeleteState_AcceptsCorrectExpandedState_DeletesState()
{
   HttpContext.Current = this.FakeHttpContext(
      new Dictionary<string, object> { { "UserExpandedState", 5 }, 
                                        { "MaxId", 1000 } },    
                                          "http://localhost:55024/api/v1/");

   string uri = "DeleteExpandedState";
   var result = Client.DeleteAsync(uri).Result;
   result.StatusCode.Should().Be(HttpStatusCode.OK);

   var state = statesRepository.GetState(5);
   state.Should().BeNull();
}

This is an example of integration test that tests Delete method of WebAPI.

WebAPI is this example hosted in memory for the purpose of integration testing.

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