During the regression testing, I have a puzzle.Test case is used to test whether the software under test.But how can I know the test case I designed has the ability to find the most bug? and in what way is it safe?
thanks a lot
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But how can I know the test case I designed has the ability to find the most bug?
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You can come to know only after its execution or from past experience of the project. There is no way we can accurately predict whether the test case will find bug or not. But generally I write test cases for the worst case.
Test cases can be written in 2 ways...positive and negative.
Positive check if functionality is working as expected or not
Negative check all other possible ways to break that functionality.
Most of our test cases are positive and along with those some negative test cases should also be written and executed. Definitely this comes with experience and good analytical skills.
E.g. A text box on web application is designed to enter numeric value. Now positive test case would be enter a numeric value in it and check if that is getting saved/stored successfully or not. Negative test case would be to enter characters, decimals, symbols, combinations, blank spaces, long strings etc. In such cases a good designed system and functionality would not save these values rather either would prompt to enter correct numeric value or would leave it blank. But if functionality was not implemented keeping this in mind then it would end up entering incorrect bad data in to the system.
I hope this is useful to you. Get back in case of suggestions.
I'm not a big fan of the hackerish mentality that test cases are designed with the sole purpose of finding bugs. That's not the entire point of a test case. If bug count is the sole purpose, wouldn't you really be measuring how bad a developer is and not how good a test case was?
Testing is the activity to reduce risk by testing the unknown. It's to make sure whatever you promise to your customers, is what you deliver. Test cases is sometimes said to be a form of a unspoken requirement. Requirements and stories are very high level, where tests are closer to the scenario level. A good test plan will have broken the requirement into different scenarios, and good test cases will cover all these different scenarios.
Thanks.I think the bug prediction ability of the test case is very important for recovering not about bug count, but the severity degree of the bug and the most bug emerged condition. All the above can help tester to improve test plan and select the next suitable test case to regression testing.