Reflection about Software Testing

1. You SHOULD never stop.
That is of course the principal, but for economical reasons it might not be worth putting in the man hours to find a bug that happens every 10000 times compared to the development of other more pressing needs. Resources are limited.

2. Yup.
However, an experienced tester will have a standard ways to smoke out the obvious bugs too.
So the keyword is experience.

3. Well, you need to at least communicate with your boss and your peers.
Then you might have to interact with users and developers.

4. It is usually better to separate the roles of developer and tester.
The main reason, in my opinion, is that as a developer you are blind for your own design.
You tend to press buttons in the right order and input the right data every time.
End users are notorious to find ways to crash programs in ways you could never thought of.
Hence, a good tester will do that job before release of the software.
Then again, it is down to the resources at hand.

Thanks for your interest in Software Testing. I just like to discuss about your questions.

Question#1.
We need to stop testing in a certain time. It may be depends on the following conditions:
- Stop the testing when the committed testing deadlines are expiring.
- Stop the testing when we are not able to detect any more errors even after execution of all the planned test Cases.
- Stop the Testing when deadlines like release deadlines or testing deadlines have reached.
- Stop the Testing when the test cases have been completed with some prescribed pass percentage.
- Stop the Testing when the testing budget comes to its end.
- Stop the Testing when the code coverage and functionality requirements come to a desired level.
- Stop the Testing when bug rate drops below a prescribed level.
- Stop the Testing when the period of beta testing / alpha testing gets over.
Also, Testing metrics can help the Test Engineer to take better and accurate decisions; like when to stop testing or when the application is ready for release; like, Percentage Completion, Percentage Test cases Passed, Percentage Test cases Failed etc.

Question#2
Yes, It is very important for a testing engineer to have experience in software development. You need to write script for test automation that is a coding. Also, you need to understand code while performing white-box testing or code inspection. You need to perform re-engineering over the developer code. So, you need software development knowledge.

Question#3
Yes, Communication is a very important skill for any tester. Tester need to describe bugs clearly for the better understand. Sometimes testers and developers are mot located in same office; on that case very good written communication is must. Also, tester needs to perform defect advocacy based on situation. So, tester should have need a very good communication skill.

Question#4
It is depends on your team structure.

You may also visit my blogs to more clarification of your questions. Please click on http://modern-testing.blogspot.com/[^]