Simplifiing NUnitForms: functional testing Windows.Forms applications

Recently, me and my team have just finished the development of a web application. There we could enjoy an extraordinary tool, called selenium (http://selenium.thoughtworks.com). Now that I come back to desktop applications, my quest is for a tool to enable TDD in the same simple and powerfull manner.

NUnitForms

In the past, our desktop applications had many benefits from using NUnitForms, an open source Windows.Forms functional testing framework. The way it works is very simple, in order to be able to simulate an action on a Windows.Forms control on a Form, NUnitForms comes with a series of wrapper classes to help.

Each standard control in System.Windows.Forms has a Tester, so for Label we have a corresponding LabelTester, for Button, ButtonTester, for TextBox, TextBoxTester and so on. Each of these testers (wrappers) make it easy for us to perform certain actions or interact with the controls, for instance we can Click a button, or type a value in a TextBox.

So if you have a very simple for like this:



where you have , two TextBox-es, a Label and a Button named: txtA, txtB, lblResult and btnCompute.

Now in order to write a simple sum test, for this form, using NUnitForms, we need to extend NUnitFormsTest and for each control we want to interact with on our form, we need to create a tester that helps us interact with that control:


public class SumFormTest:NUnitFormTest
{
private SumForm form;
private LabelTester lblResultTester;
private TextBoxTester txtATester;
private TextBoxTester txtBTester;
private ButtonTester btnComputeTester;

public override void Setup()
{
//show form
form = new SumForm();
form.Show();

//initialise testers
txtATester = new TextBoxTester("txtA");
txtBTester = new TextBoxTester("txtB");
lblResultTester = new LabelTester("lblResult");
btnComputeTester = new ButtonTester("btnCompute");
}

public override void TearDown()
{
form.Close();
}


[Test]
public void CheckOneFour()
{
txtATester.Enter("1");
txtBTester.Enter("3");

btnComputeTester.Click();
Assert.AreEqual(lblResultTester.Text,"4");
}
}



As you can see testing with NUnitForms is fairly simple.

Is this simple enough?

Now going back to web applications, there are two functional testing frameworks, that are possible the best known, for ASP.NET: selenium and NUnitAsp (http://nunitasp.sf.net ). The main difference between the two is that selenium is fit like, where you write tests as simple html tables and NUnitAsp is very similar to NUnitForms, having testers and being a strongly typed VB.NET or C# program. Between our developers and other, where I have shown both of them people tend to be more happy with Selenium. Why? The most obvious reason is that tests with selenium are much smaller, taking less time to write and thus, more maintainable. Another reason, is that with Selenium you can really see it performing the test. With NUnitAsp, you do have the advantage of speed, and you can write your own testers, but speed is very good also with Selenium.

So my idea was: Could we simplify NUnitForms? Could we make it even more appealing by being able to write less code?

With this idea in my head and with the list of selenium commands ( http://selenium.thoughtworks.com/seleniumReference.html ) I thought that my test above could be refactored as:


[TestFixture]
public class SumFormFitTest
{
private SumForm form;

[SetUp]
public void Before()
{
//show form
form = new SumForm();
form.Show();
}

[TearDown]
public void After()
{
form.Close();
}

[Test]
public void Test7()
{
NUnitFormsFit.Type(form,"txtA","3");
NUnitFormsFit.Type(form,"txtB","4");

NUnitFormsFit.Click(form,"btnCompute");
NUnitFormsFit.VerifyText(form,"lblResult","7");
}

}

Is there any reason, I should know about the testers? Couldn't I just add what I want to be done, with the form, the name of the control and maybe some arguments? Well it seems that it is possible. I just added two classes, one with some static methods that I call commands (NUnitFormsFit) like Type, Click, VerifyText, Select and a TesterFactory that can instantiate the Tester I need knowing the form it is on and it's name:


public class NUnitFormsFit
{



public static void Type(Form form, string controlName,string text)
{
TextBoxTester tester = (TextBoxTester) ControlTesterFactory.GetControlTester(controlName,form);
tester.Enter(text);
}
public static void Click(Form form, string controlName)
{
ControlTester tester = ControlTesterFactory.GetControlTester(controlName,form);
tester.Click();
}

public static void VerifyText(Form form,string controlName,string text)
{
ControlTester tester = ControlTesterFactory.GetControlTester(controlName,form);
Assert.AreEqual(text, tester.Text);
}


...


}

and:


public class ControlTesterFactory
{
public static ControlTester GetControlTester(string name, Form form)
{
ControlFinder finder = new ControlFinder(name,form);
Control control = finder.Find();

string typeName = "NUnit.Extensions.Forms."+control.GetType().Name+"Tester";

Assembly asm = Assembly.GetAssembly(typeof(ControlFinder));
Type t = asm.GetType(typeName);
ControlTester tester = (ControlTester) Activator.CreateInstance(t,new object[]{name,form});
return tester;
}
}


Only the first step ...

Some tweeks can be done like caching the testers once they have been instantiated, handling more controls with the same name , handling modal forms (which are all supported by NUnitForms, by the way) and integrating with NFit. Now how hard will it be to extend ActionFixture to enable us to simplify us to have a test like:


open || SumForm()
type || txtA || 3
type || txtB || 4
click || btnCompute
verifyText || lblResult || 7


Conclusion

Well, the code is quite simple and the extensions don't seem to be very hard to do either and I belive this can be a good step in the right direction of simplifiing NUnitForms and functional testing on Windows.Forms applications. Or maybe we will be helped by SharpRobo ( http://confluence.public.thoughtworks.org/display/SHRO/Home;jsessionid=6C4D450855CCFDC30EE0D4305D5603CE ) ?