Introduction to Application Center Test
Application Center Test (ACT) is an enterprise tool integrated into the Visual Studio .NET development environment that allows stress and regression testing of Web projects.
Note
Application Center Test is available only in the Enterprise Developer and Enterprise Architect versions of Visual Studio .NET.
ACT enables you to create VBScript or JScript routines to drive testing. Using ACT, you can create complex tests that can run repeatedly to provide baselines for performance and to ensure that software issues haven't crept into the project.
The ACT product distributed with .NET is a subset of the functionality found in Application Center, which is a Microsoft enterprise tool allowing creation and management of clustered Web servers. The Application Center Test in the Application Center suite also allows tests to be run from multiple client computers because the load generated from a single computer is limited by processor, memory, disk, or network connection at some point.
Some features of the main ACT included in Visual Studio .NET are
Integrates with the Visual Studio .NET integrated development environment (IDE)
Creates and manages cookies
Records a test script while browsing with Microsoft Internet Explorer
Supports testing of secure sockets layer (SSL) Web pages
Allows several authentication schemes
Accumulates test data for later analysis
Allows configurable simultaneous connections to drive the testing from a single computer
Is not appropriate for heavy load testing of scaleable sites
The last two items are part of the full Application Center product.
Strategy for Using ACT
The easiest way to use ACT is from the Visual Studio .NET IDE. You can add an ACT project to your solution and run it directly from Visual Studio .NET. This allows testing and editing of the script, but you don't have the same robust functionality of using ACT outside the Visual Studio .NET environment.
A second way to use ACT is in standalone mode. From the Visual Studio .NET menu, ACT is available under Visual Studio Enterprise Features. Using the standalone program enables you to set many more parameters than using the IDE integrated ACT, such as connections and iterations from the user interface. Using the standalone version also enables you to create specific users that are used to run the test, in addition to the ability to add performance counters.
For creating the test script, a recording tool is included that works like a macro recorder you learned about this week when creating macros in Visual Studio .NET. When you start recording, the recording tool opens a Microsoft Internet Explorer (IE) session, enabling you to manually browse through the target Web site, clicking on the features or links you want to test. As you're clicking around in IE, each click is recorded and the data being downloaded to the browser is recorded. This is the basis for the test.
Tip
For basic testing, use the integrated version; for more complicated test setup, use the standalone version to help you with settings. The version of ACT that comes with Visual Studio .NET isn't adequate for high-end load testing of Web projects because it doesn't allow multiple client computers to be controlled. You need the full version of Application Center to do that.
If you use the standalone ACT or the integrated ACT, a script file is created that you'll probably want to modify and tune. When you take a careful look at the script, you'll see that it's pretty simple. All features of ACT and the interaction with the browser can be scripted.
As you'll see later, all the ACT settings except the scripts are stored in XML files. If you're motivated enough and can remember last week when you learned how to work with XML, you can modify the XML files to adjust to interfaces in any way you choose.