Asp.net MVC JsonResult, Anonymous types and Testing

This article is an explanation on how to access the data from a JsonResult for using it in your unit testing

The JsonResult type has a property called Data of type Object that you can parse if you have used a concrete object as your data for example:

Model

public class Person
  {
    public int Id { get; set; }
    public string Name { get; set; }
    public string Age { get; set; }
  }

Controller Action

public JsonResult Index()
{
  //Logic ....
  var person = new Person
                      {
                          Id = 1,
                          Name = "Nadeem",
                          Age = "24"
                      };
  return Json(person);
}

Unit Test

[Test]
public void Testing()
{
  var controller = new HomeController();

  var result = controller.Test();
  var data = result.Data as Person; //you can now access the Person properties

  //Assert
}

---

This is all good but we get stuck if we want to pass an anonymous object to our JsonResult there is no way to cast to something to access an anonymous object properties

the solution is i made two custom helper methods that we can use to get values from a JsonResult.Data object
ill follow after with an example of using it

The custom helper:

public static class Helper
{
  public static object GetValue(this JsonResult result,string propertyName)
  {
    IDictionary<string, object> wrapper = new System.Web.Routing.RouteValueDictionary(result.Data);
    return wrapper[propertyName];
  }
  public static T GetValue<T>(this JsonResult result, string propertyName)
  {
    return (T) GetValue(result, propertyName);
  }
}

Example:

Controller Action

public JsonResult Index()
{
  //Logic ....
  return Json(new {number = 1});
}

Unit Test

[Test]
public void Testing()
{
  var controller = new HomeController();

  var result = controller.Index();

  Assert.AreEqual(1, result.GetValue<int>("number"));
}

This is how to test a JsonResult using  anonymous types

 

For the fun of it we can make a helper that returns a dynamic type (but its not as efficient as the top solution)

The custom helper:

public static dynamic ToDynamic(this JsonResult jsonResult)
{
  var expandoObject = new ExpandoObject();
  var expandoCollection = (ICollection<KeyValuePair<string, object>>)expandoObject;
  var dataWrapper = new RouteValueDictionary(jsonResult.Data);
  foreach (var kvp in dataWrapper)
  {
    expandoCollection.Add(kvp);
  }
  dynamic eoDynamic = expandoObject;
  return eoDynamic;
}

Unit Test

[Test]
public void Testing()
{
  var controller = new HomeController();

  var result = controller.Index();

  Assert.AreEqual(1, result.ToDynamic().number);
}

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