In his post Six Things That Go Wrong With Discussions About Testing, James Bach lists six different things that can often go wrong when testers are discussing testings. His six reasons can be summarized as testers misunderstanding the purposes of testing and not following the proper procedure when it comes to testing.
Your goal when testing is to discover any vulnerabilities in your program, but also to find strengths and things your program is doing well. This covers James’ first two points. When it comes to testing, quality is much more important than quantity. It is better to have a more complete coverage of your program and all its branches than to have a bunch of tests doing the same thing and missing different parts of your program. This is why it is important to think of tests as events instead. What is important is what your test is testing and how it goes about that, and it shouldn’t be thought of as some ‘Generic X Test.’
Often times people get carried away with automated testing and rely too much on it. While it is good to use automated testing, developers have strength far beyond that, and should use automated tests as tools to better accomplish effective testing, not as automated workers that do your work for you. Thinking of automated tests in this way also distracts from the purpose of testing, and makes it easier to forget why you should run certain tests in the first place.
James’ last point is probably his most important one. Testing isn’t just some set task that can be navigated a certain way every time. What I’ve learned this year is that testing is about thinking critically about a program and the way it COULD act, and design your tests according to those parameters. Consider where things can go wrong, and try to test the strength of weak parts of your code. But most importantly, be ready to learn, as every program has a different set of tests with a different strategy that is most effective for testing. Testing is a dynamic thing, and testers must be dynamic people.