Unit testing the action that invokes the session object

Question

How can I unit test a method that uses a session object inside its body?

Let's say I have the following action:

[HttpPost]
public JsonResult GetSearchResultGrid(JqGridParams gridParams, Guid campaignId, string queryItemsString)
{
    var queryItems = new JavaScriptSerializer().Deserialize<IList<FilledQueryItem>>(queryItemsString);
    IPageData pageData = gridParams.ToPageData();
    var extraFieldLinker = SessionHandler.CurrentExtraFieldsLinker;
    var searchParams = new SearchParamsModel(extraFieldLinker, queryItems);
    IList<CustomerSearchResultRow> searchResults = null;
    searchResults = _customerService.SearchCustomersByUrlAndCampaign(campaignId,
        searchParams.SearchString,
        searchParams.AddressFilterPredicate,
        pageData);
    return GetGridData<CustomerSearchResultGridDefinition, CustomerSearchResultRow>(searchResults, pageData);
}

I did the following unit tests, which so far have not been run due to the session:

[Test]
public void CanGetSearchResultGrid()
{
    //Initialize
    var mockJqGridParams = new Mock<JqGridParams>();
    var mockPageData = new Mock<IPageData>();
    IPagedList<CustomerSearchResultRow> mockPagedResult = new PagedList<CustomerSearchResultRow>(mockPageData.Object);
    var guid= Guid.NewGuid();
    const string searchString =
        "[{\"Caption\":\"FirstName\",\"ConditionType\":\"contains\",\"Value\":\"d\",\"NextItem\":\"Last\"}]";
    Func<Address,bool> addressFilterPredicate = (x => true);

    //Setup
    mockJqGridParams.Setup(x => x.ToPageData()).Returns(mockPageData.Object);
    _customerService.Setup(x => x.SearchCustomersByUrlAndCampaign(guid, searchString, addressFilterPredicate, mockPageData.Object))
        .Returns(mockPagedResult);

    //Call
    var result = _homeController.GetSearchResultGrid(mockJqGridParams.Object, guid, searchString);

    mockJqGridParams.Verify(x => x.ToPageData(), Times.Once());
    _customerService.Verify(x => x.SearchCustomersByUrlAndCampaign(guid, searchString, addressFilterPredicate, mockPageData.Object)
        , Times.Once());

    //Verify
    Assert.That(result, Is.Not.Null);
    Assert.That(result, Is.TypeOf(typeof(JsonResult)));
}

And the method from the assistant, of course:

   public static ExtraFieldsLinker CurrentExtraFieldsLinker
    {
        get
        {
            object extraFieldLinker = GetSessionObject(EXTRA_FIELDS_LINKER);
            return extraFieldLinker as ExtraFieldsLinker;
        }
        set { SetSessionObject(EXTRA_FIELDS_LINKER, value); }
    }

Answer 1

I solved similar problems (using static data accessories that are not friendly to each other, in particular HttpContext.Current), by transferring access to another object and accessing it through the interface. You can do something like:

pubic interface ISessionData
{
    ExtraFieldsLinker CurrentExtraFieldsLinker { get; set; }
}

public class SessionDataImpl : ISessionData
{
    ExtraFieldsLinker CurrentExtraFieldsLinker
    {
        // Note: this code is somewhat bogus,
        // since I think these are methods of your class.
        // But it illustrates the point.  You'd put all the access here
        get { return (ExtraFieldsLinker)GetSessionObject(EXTRA_FIELDS_LINKER); }
        set { SetSessionObject(EXTRA_FIELDS_LINKER, value); }
    }
}

public class ClassThatContainsYourAction
{
    static ClassThatContainsYourAction()
    {
        SessionData = new SessionDataImpl();
    }

    public static ISessionData SessionData { get; private set; }

    // Making this access very ugly so you don't do it by accident
    public void SetSessionDataForUnitTests(ISessionData sessionData)
    {
        SessionData = sessionData;
    }

    [HttpPost]
    public JsonResult GetSearchResultGrid(JqGridParams gridParams,
        Guid campaignId, string queryItemsString)
    {
        var queryItems = // ...
        IPageData pageData = // ...

        // Access your shared state only through SessionData
        var extraFieldLinker = SessionData.CurrentExtraFieldsLinker;

        // ...
    }
}

unit test ISessionData mock- GetSearchResultGrid.

Injection Dependency - .

ISessionData instanced , . , , , . , , , .