What is the best way to test a RedirectToAction?

Question

I have the following condition

if (_ldapAuthentication.IsAuthenticated (Domain, login.username, login.PassWord))
{
    _ldapAuthentication.LogOn (indexViewModel.UserName, false);
    _authenticationService.LimpaTentativas (login.username);
    return RedirectToAction ("Index", "Main");
}

being true, it redirects to another page .. what would be best to do a test?

Answer 1

In a unit test, you'd just assert on the ActionResult returned by your controller.

//Arrange
var controller = new ControllerUnderTest(
                        mockLdap,
                        mockAuthentication
                     );

// Mock/stub your ldap behaviour here, setting up 
// the correct return value for 'IsAuthenticated'.

//Act
RedirectResult redirectResult =
     (RedirectResult) controller.ActionYouAreTesting();

//Assert
Assert.That( redirectResult.Url, Is.EqualTo("/Main/Index"));

Answer 2

To avoid possible InvalidCastExceptions in your unit test, this is what i always do:

//Arrange
var controller = new ControllerUnderTest(
                        mockLdap,
                        mockAuthentication
                     );

// Mock your ldap behaviour here, setting up 
// the correct return value for 'IsAuthenticated'.

//Act
var result = controller.ActionYouAreTesting() as RedirectToRouteResult;

// Assert
Assert.NotNull(result, "Not a redirect result");
Assert.IsFalse(result.Permanent); // Or IsTrue if you use RedirectToActionPermanent
Assert.AreEqual("Index", result.RouteValues["Action"]);
Assert.AreEqual("Main", result.RouteValues["Controller"]);