A tester is usually bound by the constraints of specifications when he does functional testing. But what about usability? How much should the tester’s imagination be allowed to flow?
Read carefully– this is important:
The specification does not bind you, as a tester. The specification provokes you. In fact, the spec, the product, the things people say on the project– all of it is provocative to the tester. It might be where we start, but not where we end. If the product behaves in some important way (important either positively or negatively), then it is generally the role of the tester to test it, even if there is nothing in the spec about that behavior.
Doing testing well requires a great deal of imagination.
I think a tester is actually bound by six things that come to mind as I write this: the mission, project culture, the paticular constraints of the project, and the skill and knowledge of the tester. All of these except that last one are to some extent negotiable:
Mission: This is the problem that your clients want you to solve for them; the outcome they want you to achieve. If you don’t honor your mission, you will not gain credibility or retain respect. Be sure that you negotiate a mission you are capable of fulfilling; and be sure that the story of your testing features the mission as its primary plot point. Is usability testing a part of your mission?
Project Culture: The other people on your project have expectations about what you will or will not do. These bind you. You can challenge those expectations and suggest alternatives, but you have to be careful about that. If usability is part of your mission, what methods of usability testing are acceptable or expected within your organization?
Project Constraints: On your project, you don’t have all the time and money to do everything you might find useful or interesting. You may need to find inexpensive ways to do the testing that your strategy calls for. You may need to acquire special tools, or use tools that don’t do everything you wish they did. What kind of usability testing is it even possible to do on your project?
Tester Skill & Knowledge: Even if you were granted permission and resources to do everything you want to do, you would still be limited to the things that you know how to do. If you want to do testing well, you need enough command of testing practices and tools to make that possible. One common problem with testers is that they don’t do enough to educate themselves. Do you know how to do usability testing?
I realize that this is not a detailed answer to your question. What I’m trying to do is frame a way for you to think the issue through for yourself.
Ethical Standards: A tester is bound by ethical standards not to, for instance, lie about the results of the tests, or to misrepresent his ability to do the work. Are you suggesting usability testing for selfish reasons, or do you really believe it will help your client?
Legal Standards: A tester is bound by legal standards. In some cases, there are laws, such as Sarbanes-Oxley or HIPAA, which guide how you must test. Is there any legal reason why you must or must not perform usability testing?