Is expected result a must for every test?

The inspiration for me to write this is an interesting discussion that I came across in one of the forums. The topic of the debate was – whether every test needs to have an expected result.

The moment I glanced the topic I was very sure about the answer to it – YES every test needs an expected result. Without any expectation any tests were useless. I penned down my feelings and waited for other opinions. Though most of them voiced the same feeling as mine, there were a few who thought differently. Some of non-functional testers did not need an expectation to complete their tests at first. Some of them even asked me whether you had any problems because you had an expected result for your test case.

Now after some days of thinking over the topic I still feel that a test case needs to have an expected result as majority of my fellow testers felt.

However, in some cases, having a strict expected result can narrow down your thought process. In such cases we can write a test case by providing a very generic expected result giving enough space for the testers to ponder and play around. Also if you are doing an exploratory testing may be you would get test cases without any expected results. But even there, you would expect some results based on your previous experience. In some kind of testing especially performance tests, the expected result evolve over time.

You can view the full discussion thread here. And maybe think over the topic and can pen down what you feel about it.