Challenges and Perils of Testing Database Manipulation Code

Software testing enable development teams to maintain the quality of a software system while it evolves. The database manipulation code requires special attention in this context. However, it is often neglected and suffers from software maintenance problems. In this paper, we investigate the current state-of-the-practice in testing database manipulation code. We first analyse the code of 72 projects mined from Libraries.io to get an impression of the test coverage for database code. We confirm that the database is poorly tested: 46% of the projects did not cover with tests half of their database access methods, and 33% of the projects did not cover the database code at all. To understand the difficulties in testing database code, we analysed 532 questions on StackExchange sites and deduced a taxonomy. We found that developers mostly look for insights on general best practices to test database access code. They also have more technical questions related to DB handling, mocking, parallelisation or framework/tool usage. This investigation lays the basis for future research on improving database code testing.