How many test cases are enough?

3 Comments

1. tridung

   May 19, 2015 at 3:25 pm

   I think we should define the “enough” first. We can list out the number of test cases when you read the specs – acceptance criteria. If we know the scope for the build/release then we can estimate the test cases.
   Should we ask how many percentages was done in testing instead?
2. Thanh Huynh

   May 19, 2015 at 3:38 pm

   Good question but it’s a tough one Thong.

   I think Dung makes a good point. Defining “enough” is important in this case. However, it’s not an easy task.

   When mentioning about writing test cases/test ideas, it looks like we can always have more test cases/test ideas to write and it seems to be never “enough”. Of course, if we don’t have all the time in the world, the number of tests/test cases are limited by:

   1) Release schedule
   2) Risks (if we test and not test a case)

   Also, I’m trying to avoid counting things to correlate to quality of testing when doing test. I put more focus on how good are our tests are. E.g.: I would rather have 5 good test cases than 100 test cases which does not reveal anything about the system under test.
3. Thong Khuat

   May 22, 2015 at 5:52 pm

   Agree with Thanh & Dung, by some reasons I often get this question from an interviewer 😀 I always want to tell them that: “Hey, I will write until you get stress with the reviewing and tell me to stop. We have no limitation until you know it is enough and you don’t need the answer, you idiot!”.

   I often apply the 80/20 rule in the test case numbers and what I care is whether those 20% test cases cover most of the scenarios the end-users often get into the product.