I am often asked why I teach that system testers should use code coverage tools when in most organizations, system testers don’t have access to the code.
Short Answer: Because, typically, even a very comprehensive set of black box test cases only covers about 30%-40% of the logic in a program. If you are comfortable shipping a system where 60%-70% of the logic has not been tested by the system test team, then you don’t need a code coverage tool.
Tags: code, code coverage, system tester
Hi
I am not sure if I have understood the relevance between the question and the answer!
Question – Why should system testers learn code coverage (or/and tools) when they do not have access to the code?
Answer – Since management has to make a decision if a build should be shipped which has only got 40% code coverage.
In my opinion, it is important for system testers to know code coverage/tools AND at the same time, the management has to be explained the importance of this metric.
Your thoughts please?
Gaurav,
I agree. Educated management is so important. Managers need to understand the implications of values for metrics such as cyclomatic complexity, statement coverage, branch coverage, etc. Managers then need to work with the technical testing staff to determine the proper course of action based on these metrics.
Managers need more than just a surface understanding of these metrics. I have seen managers go to the extreme and require 100% code coverage at the system level. Thirty percent code coverage may be inexcusable, but 100% coverage at the system level is usually infeasible.
A test professional can never have enough education.
Tim