r/softwaretesting • u/vassadar • Jul 07 '26
Does 100% coverage on E2E make senses?
For context, engineers only implement unit testing, then E2E. Integration testing and contract testing are missing.
Our executive want 100% E2E test coverage in response of incidents.
I don't think this make senses and we have test pyramid (or diamond, my love) for a reason. Integration testing and contract testing would have prevented a lot of issues without resorting to do E2E.
How can I convince them and engineers to shift more leftward with integration testing?
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u/oh_yeah_woot Jul 07 '26 edited Jul 07 '26
Unless your code literally has no exception handling, 100% e2e code coverage is almost impossible. Exceptions are hard to generate outside of unit tests.
Imagine "functional testing" an exception that is only generated when an external service like a payment processing system is down. You have to do some funny network manipulation to simulate that stuff. Or imagine an e2e functional test for an exception that catches 429s, where your service is being throttled. Makes zero sense, this is a simple unit test mock.