Saturday, April 26, 2008

Fantasy about Record and Playback

Many testers do not have strong programming skills. With the scripting problems, it leads testers to use record and playback techniques. There indeed are many tools that allow scripts to be recorded and then played back, using screen captures for verification.

Every automated test tool vendor will tell you that their tool is "easy to use" and that your non-technical user-type testers can easily automate all of their tests by simply recording their actions, and then playing back the recorded scripts. This one statement alone is probably the most responsible for the majority of automated test tool software that is gathering dust on shelves in companies around the world. We have seen the vendor’s sample applications. We have seen the tools play nice with those applications. And we try to get the tools to play nice with our applications just as fluently. Inherently, project after project, we do not achieve the same level of success.

The Record / Playback Myth:
The problem that an always crop up is that the layouts are changed, invalidating the screen captures and then the interface controls change making playback fail. Now the scripts must be re-recorded from scratch. Record and playback tools provide an easy way to create throwaway test suites.

You can easily notice that identification of controls and windows is through the co- ordinates of the screen. The scripts will be broken easily when there is a change in resolution of the screen.

The scripts resulting from this method contain hard-coded values, which must change if anything at all changes in the application.

If the tester makes an error entering data, etc., the test must be re-recorded. If the application changes, the test must be re-recorded.

Sometimes this manifesto is hard to explain to people who have not yet performed significant test automation with these capture \ replay tools. But it usually takes less than a week, often less than a day, to hear the most repeated phrase: "It worked when I recorded it, but now it fails when I play it back". But this is true in case of record and play back tool.

No comments: