A string utilities plug-in

I love products with extensibility. Obviously, a product must work well right out-of-the-box, but assuming that precondition, that a product works the way it should, my next feature request is that it have some sort of plug-in API. AutomatedQA products, of course, have this almost to excess. With version 4 of TestComplete, the plug-in API was largely rewritten, requiring all my TestComplete 3 plug-ins to be reworked. At first, I wasn't too happy about this, but I'm finally starting to make some progress with the new SDK, and my plug-ins are again taking shape. As a result, I've decided to share what I'm learning, and to share the results of my efforts as well. This is the first of what will (hopefully) be a multi-part series on creating plug-ins for TestComplete 4. These articles/plug-ins will consist of my actual completed custom plug-ins with an install for adding them to TestComplete, a help file, source code and an article that discusses what I learned as I worked on the project. I'll do this in ascending order of complexity; for example, today's project is a very simple plug-in that basically provides a library of common routines. The next project will demonstrate the process of having your plug-in listen for TestComplete events.

A few more thoughts:

This article is not a tutorial into the basics and inner workings of the TestComplete plug-in SDK. AutomatedQA has provided some materials on that (including, by the way, an SDK help file that gets installed to your C:\Program Files\Automated QA\TestComplete 4\Help directory when you install the SDK - important to note). Plan on researching the provided SDK and on digging through the TestComplete and TestCompleteInternal type libraries; this is where I've gotten most of my information. If you're not familiar with the published SDK, you should probably do some reading, but even without that, you can get something out of these articles - and at the very least, you can just install and use the plug-ins.

So, without further ado…

A Common Routines Plug-in

Our first plug-in is one that simply provides a library of common routines. A question that came up repeatedly when I was with AutomatedQA was how to best manage sets of common or shared routines. There are pluses and minuses to the various (see my previous article: To Plug-in or Not to Plug-in) but the plug-in approach has advantages in that it offers ease of deployment and ease of use - no need to add units to projects or to make sure that you have the latest version of an ODT object. With a plug-in, the functionality is literally built into TestComplete. With this in mind, I've implemented a set of odd string management routines as a simple runtime plug-in.

"Runtime plug-in"?

This is probably a good time to remind you of some of the architecture changes in version 4 of the TestComplete SDK. The new version does a particularly good job of enforcing the separation of plug-in registration, design-time and run-time parts of the plug-ins. For instance, registration is the part of your extension that registers the plug-in with TestComplete - telling it how to find and create the actual plug-in object when it needs it…

Such as when it's being referenced in design-time: does it have settings (options)? Does it provide a scripting interface (does it appear in the code completion window)? Does it have panels that appear in the TestComplete IDE?. In the case of the string utilities plug-in, it needs to run at runtime; it needs to provide information to the code completion window, but that's about it. No panels, no settings, no event listening… nothing fancy. You'll note that the SDK samples provided by AutomatedQA are available for either Delphi or MS Visual C++. No C# at this time. As a result, I'm creating my plug-ins in Delphi.

Here's an overview of the entities in the plug-in project. Make sure you read both this article and the TestComplete SDK documents to get a good feel for what's going on.

In addition to the entity overview, I'm including this simple sequence diagram to help explain some of the responsibilities of the various objects in the string utilities plug-in project.

This is the interface that describes what the tsStrUtils plug-in makes available for scripting purposes.

For this particular plug-in, there are only methods (operations).

You can see that this is the same list that appears in the code completion window:

TtsStrRuntimeObj is the object that handles the implementation of the script calls to the StrUtils object when a test is playing back. If TestComplete needs to call methods of your plug-in, it creates an instance of your plug-in's runtime object; see the SDK interface ItcRuntimeObjectFactory and its CreateRuntimeObject method - this interface and method is implemented by the plugin object; in this case that's the TtsStrUtilsPlugin.CreateRuntimeObject method. You can find that in the source code of this article. Note that in the case of this plug-in, the TtsStrUtilsPlugin class is basically a pass-through to the TtsStringUtils static class found in tsUtilityClasses.pas. This is a collection of string utilities I've been using for years. I wrote some of them, others are from code I've picked up over time and, unfortunately, have lost the origin. I wish to correctly credit those who wrote the code, so if you recognize any of it, please let me know. In any case, it's some common routines - the point is that you can take the same approach with your own libraries.

This is the class that is considered the actual "plug-in" object. In the case of this plug-in, there's not just a great deal to it; it basically tells TestComplete some information about itself and where to get the runtime object.

You can find out just about everything you need to know about this Registrator class by reading the SDK docs. This object takes care of registering the actual plug-in with TestComplete.

Making use of the plug-in could not be simpler. Once it's installed, the methods of the StrUtils plug-in are available to you via the code completion window in TestComplete. You can make use of them in the same way you would any other object in TestComplete. There are comments about the methods in the code completion window, and I've provided a help file too, as part of the install.