Post summary: re-use of page objects code through inheritance.

Inheritance is one of the pillars of object-oriented programming. It is a way to re-use functionality of already existing objects.

Reference

I’ve started a series with details of Advanced WPF desktop automation with Telerik Testing Framework and TestStack White. The sample application can be found in GitHub SampleAppPlus repository.

Abstract class

An abstract class is one that cannot be instantiated. An abstract class may or may not have abstract methods. If one method is marked as abstract then its containing class should also be marked as abstract. We have two similar windows with text box, save and cancel button that is shown on both of them. AddEditText class following Page Objects pattern. It is marked as abstract thought. It has an implementation of all three elements except TextBox_Text.

public abstract class AddEditText : XamlElementContainer
{
	protected string mainPath =
		"XamlPath=/Border[0]/AdornerDecorator[0]/ContentPresenter[0]/Grid[0]/";
	public AddEditText(VisualFind find) : base(find) { }

	protected abstract TextBox TextBox_Text { get; }
	private Button Button_Save
	{
		get
		{
			return Get<Button>(mainPath + "Button[0]");
		}
	}
	private Button Button_Cancel
	{
		get
		{
			return Get<Button>(mainPath + "Button[1]");
		}
	}

	public void EnterText(string text)
	{
		TextBox_Text.Clear();
		TextBox_Text.User.TypeText(text, 50);
	}

	public void ClickSaveButton()
	{
		Button_Save.User.Click();
		Thread.Sleep(500);
	}

	public void ClickCancelButton()
	{
		Button_Cancel.User.Click();
	}
}

Add Text page object

The only thing we have to do in Add Text window is to implement TextBox_Text property. All other functionality has already been implemented in AddEditText class.

public class AddText : AddEditText
{
	public static string WINDOW_NAME = "Add Text";
	public AddText(VisualFind find) : base(find) { }

	protected override TextBox TextBox_Text
	{
		get
		{
			return Get<TextBox>(mainPath + "TextBox[0]");
		}
	}
}

Edit Text page object

In Edit Text page object we have to implement “TextBox_Text” property. Also on this window, there is one more element which needs to be defined.

public class EditText : AddEditText
{
	public static string WINDOW_NAME = "Edit Text";
	public EditText(VisualFind find) : base(find) { }

	private TextBlock TextBlock_CurrentText
	{
		get
		{
			return Get<TextBlock>(mainPath + "TextBlock[0]");
		}
	}

	protected override TextBox TextBox_Text
	{
		get
		{
			return Get<TextBox>(mainPath + "TextBox[1]");
		}
	}

	public Verification VerifyCurrentText(string text)
	{
		return BaseTest.VerifyText(text, TextBlock_CurrentText.Text);
	}
}

Conclusion

Inheritance is a powerful tool. We as automation engineers should use it whenever possible.

Automation Rhapsody

Advanced WPF automation – page objects inheritance