Watin Testing Pattern

On my current project we have zero unit tests. I inherited the application and the existing unit tests where such a mess it was better to just kill em and start over. I would normally start from the data layer and work up, but since we are working toward a release in a couple weeks I need the best bang for my buck. So I decided to start with some UI functional tests, these will also be a major asset once we start really refactoring the application.

I have used Watir in the past, but since this is a .NET project I think it makes more sense to go with Watin. Before getting started with Watin I did some research to see what the "best practices" were. The watin site has some good samples, but not much in the way of patterns or best practices. The site does link to this blog post from Richard Griffin which outlines a design pattern, but the pattern is a little too procedural for my liking. Perhaps it is all the ruby lately, but more and more I want clean object oriented solutions whenever possible.

So I came up with my own pattern. I wanted to completely hide the IE object and make writing tests as intuitive and easy as possible, while following DRY and KISS. So I decided to start with an object for each page, here is what I started with.

public class HomePage : IE
{
public const string HomePageURL = "default.aspx";
public HomePage() : base (ConfigurationManager.Host

+ HomePageURL) { }

}

Instead of playing around with passing the IE object around, I decided to just inherit from it. In your test if you want to test the homepage you just have to say

HomPage home = new HomePage();

and use the home object in the exact way you would the IE object. Then I include properties for the various textboxes and such on the page:

public TextField UserIDField {

get{ return TextField(Find.ByName("txtUsername")); } }

public TextField PasswordField {

get { return TextField(Find.ByName("txtPassword")); } }

public Button ContinueButton {

get { return Button(Find.ByName("btnContinue")); } }

and also methods for the main actions on the page:

internal void Login(string username, string password)
{
UserIDField.TypeText(username);
PasswordField.TypeText(password);
ContinueButton.Click();
}

Now if I want to write a test to test logging in my test looks like this:

[Test]
public void Login()
{
HomePage home = new HomePage();
home.Login("james", "password");
Assert.IsTrue(home.ContainsText("My Stuff"));
//more assertions here
home.Close();
}

The only other thing I found I needed was a way to change what page object I am working with, so I added another constructor that lets you "switch" the page you are on:

public HomePage(IE instance) :

base(instance.InternetExplorer) {}

This way I can add methods that return a different page like this one:

internal UserRegistrationPage GoToUserRegistration()
{
UserRegistrationLink.Click();
return new UserRegistrationPage(this);
}

You would only need this for tests that move from page to page, otherwise you could just create a new page object. So far it has been working great, I will post an update if I encounter any issues or make any major changes. If I find the time I am going to try and add a feature to the Watin recorder to generate these page objects, it wouldn’t be too hard and it would make it really easy to write Watin tests.

While twittering about it I talked to Phil Haack and he is using a similar pattern on subText, though there are a couple differences like he keeps the IE object separate. (you can grab the source and check it out if you want to see another option.

Download the sample files:

WatinFiles-1.zip

-James