  To assess the quality of a test suite, one can rely on mutation testing,
which computes whether the overall test cases are adequately exercising the
covered lines. However, this high level of granularity may overshadow the
quality of individual test methods. In this paper, we propose an empirical
study to assess the quality of test methods by relying on mutation testing at
the method level. We find no major differences between high-quality and
low-quality test methods in terms of size, number of asserts, and
modifications. In contrast, high-quality test methods are less affected by
critical test smells. Finally, we discuss practical implications for
researchers and practitioners.
