MSDN Magazine - March 2008 - (Page 97)

Web UI Automation with Windows PowerShell DR. JAMES MCCAFFREY indows PowerShell™, the new Microsoft command shell and scripting language, is a great platform for several kinds of lightweight test automation. In this month’s Test Run column, I show you how to use Windows PowerShell to create quick and easy UI test automation for any kind of Web application by automating Internet Explorer®. This column is primarily intended for beginners, but experienced engineers will find some interesting information here, too. Before you start, make sure you have added whatever sites you are going to test to your “Trusted Sites” list in Internet Explorer— otherwise the scripts may not work. I begin my automation demonstration by issuing the Windows PowerShell command: PS C:\> $ie = new-object -com “InternetExplorer.Application” W This creates an instance of the classic InternetExplorer COM automation object from the SHDocVw.dll library. The new-object keyword is a Windows PowerShell cmdlet (pronounced commandlet). There are approximately 130 cmdlets, and they form the heart of Windows PowerShell functionality. You can explore what the cmdlets are by running get-command and you can always get help on a cmdlet by running get-help Command. I supply a -com switch (which is actually a shortcut for -comObject) to new-object. This specifies that I am instantiating a classic COM object using the object’s ProgID rather than instantiating a managed object. I store the resulting object into the $ie variable (all Windows PowerShell variables are preceded by a $ character, making them easy to distinguish from other token types). Next, I use the Navigate method to load my dummy MiniCalc Web application under test into my browser automation object: PS C:\> $ie.navigate(“http://localhost/MiniCalc/Default.aspx”) PS C:\> $ie.visible = $true Figure 1 Web App UI Automation with Windows PowerShell Another Windows PowerShell discovery capability is command completion. For instance, I can type “$ie.vi” and then press the Tab key, and Windows PowerShell will finish typing my ie.visible statement for me. These discovery features in Windows PowerShell are huge time savers. Next, I obtain references to all input controls on my application under test: PS PS PS PS PS C:\> C:\> C:\> C:\> C:\> $doc $tb1 $tb2 $add $btn = = = = = $ie.document $doc.getElementByID(“TextBox1”) $doc.getElementByID(“TextBox2”) $doc.getElementByID(“RadioButton1”) $doc.getElementByID(“Button1”) One of the great features of Windows PowerShell is that it can help you explore an object’s capabilities. With older scripting technologies, if I didn’t know that the InternetExplorer object has a Navigate method, I’d be forced to look that information up using some sort of external reference. But with Windows PowerShell, I have several quick ways to see the available methods and properties for an object. For example, I can use tab completion by typing “$ie.” and then pressing the Tab key. After each key press, an available property or method will be displayed. I can also use the getmember cmdlet to get a list of all available properties and methods, and their signatures: PS C:\> $ie | get-member | more I use the Document property to fetch the active document and then use the getElementById method to obtain references to each control. Notice that for this technique to work, all of my HTML elements must have an ID value. In most situations this is not a problem. If you create your Web application with Visual Studio®, all controls automatically receive IDs. If you are writing test automation for a Web application where the elements do not have IDs, you can also use the getElementsByTagName method to return a collection of elements and then access a specific element by index. Next, my automation simulates some user input: PS PS PS PS C:\> C:\> C:\> C:\> $tb1.value = 5 $tb2.value = 7 $add.checked = $true $btn.click() march2008 97

Table of Contents Feed for the Digital Edition of MSDN Magazine - March 2008

MSDN Magazine - March 2008 Contents Toolbox CLR Inside Out Data Points Advanced Basics Office Space Introducing ASP.NET MVC Loosen Up CI Server Performance Office Development Test Run Security Briefs Extreme ASP.NET Foundations .NET Matters {End Bracket}

MSDN Magazine - March 2008

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