We would like to shift quality left and motivate developers to write integration tests - both narrow and broad. The biggest challenge is to introduce metrics we could use for measuring the effectiveness of the tests. Code coverage is out of scope as it does not tell much in integration test space. We thought of some sort of limited coverage measurement - checking if collaboration points like app to database, app to external service are covered by tests. Another option was to check how the test passing rate changes if we mutate the response from external dependencies. Is there any tool supporting to extract such metrics or is there a better approach to check effectiveness? Our domain is Java.
Update: The metric is used to give feedback to developers on their progress, later we want to use some of the metrics for setting quality gates