Add sessions for ASP.NET 5 controller unit tests - unit-testing

Question

After we added sessions in our asp web app, now our controller unit tests fail:
data_browser.Tests.HomeControllerTests.Index [FAIL]
System.NullReferenceException : Object reference not set to an instance of an object
Tests fail on a statement where we use sessions:
HttpContext.Session.SetString("games", JsonConvert.SerializeObject(games));
Looks like as a session service needs to be added. In our app it is done through Startup class's methods:
public void ConfigureServices(IServiceCollection services)
{
// Add MVC services to the services container.
services.AddMvc();
services.AddSession();
services.AddCaching();
}
and
public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
{
app.UseSession();
...
}
But when we unit test, we just instantiate our controller smth like this:
HomeController homeCtrler = new HomeController();
JsonResult jsonResult = (JsonResult)homeCtrler.Smth();
Assert.Eq(bla, bla);
So is there a way to inject sessions for controller in asp.net 5 unit tests?

Answer 1

An example (from https://github.com/aspnet/MusicStore/blob/master/test/MusicStore.Test/ShoppingCartControllerTest.cs):
// Arrange
var httpContext = new DefaultHttpContext();
httpContext.Session = new TestSession();
var controller = new ShoppingCartController()
controller.ActionContext.HttpContext = httpContext;
// Act
var result = await controller.Index();
//--------------
class TestSession : ISession
{
private Dictionary<string, byte[]> _store
= new Dictionary<string, byte[]>(StringComparer.OrdinalIgnoreCase);
public IEnumerable<string> Keys { get { return _store.Keys; } }
public void Clear()
{
_store.Clear();
}
public Task CommitAsync()
{
return Task.FromResult(0);
}
public Task LoadAsync()
{
return Task.FromResult(0);
}
public void Remove(string key)
{
_store.Remove(key);
}
public void Set(string key, byte[] value)
{
_store[key] = value;
}
public bool TryGetValue(string key, out byte[] value)
{
return _store.TryGetValue(key, out value);
}
}