Can operational profile coverage explain post-release bug detection?

To deliver reliable software, developers may rely on the fault detection capability of test suites. To evaluate this capability, they can apply code coverage metrics before a software release. However, recent research results have shown that these metrics may not provide a solid basis for this evaluation. Moreover, the fixing of a fault has a cost, and not all faults have the same impact regarding software reliability. In this sense, operational testing aims at assessing parts of the system that are more valuable for users. The goal of this work is to investigate whether traditional code coverage and code coverage merged with operational information can be related to post-release bug detection. We focus on the scope of proprietary software under continuous delivery. We performed an exploratory case study where code branch and statement coverage metrics were collected for each version of a proprietary software together with real usage data of the system. We then measured the ability to explain the bug-fixing activity after version release using code coverage levels. We found that traditional statement coverage has a moderate negative correlation with bug-fixing activities, whereas statement coverage merged with the operational profile has a large negative correlation with higher confidence. Developers can consider operational information as an important factor of influence that should be analysed, among other factors, together with code coverage to assess the fault detection capability of a test suite.