  A key aspect of ensuring the quality of a software system is the practice of
unit testing. Through unit tests, developers verify the correctness of
production source code, thereby verifying the system's intended behavior under
test. However, unit test code is subject to issues, ranging from bugs in the
code to poor test case design (i.e., test smells). In this study, we compare
and contrast the occurrences of a type of single-statement-bug-fix known as
"simple stupid bugs" (SStuBs) in test and non-test (i.e., production) files in
popular open-source Java Maven projects. Our results show that SStuBs occur
more frequently in non-test files than in test files, with most fix-related
code associated with assertion statements in test files. Further, most test
files exhibiting SStuBs also exhibit test smells. We envision our findings
enabling tool vendors to better support developers in improving the maintenance
of test suites.
