Measurement and detection of redundancy in test suites attempt to achieve test minimization which in turn can help reduce test maintenance costs, and to also ensure the integrity of test cases. Test suite reduction based on coverage information has been discussed in many previous works. However, the applications of such techniques on real test suites and realistic measurements of redundancy have not yet been experimented thoroughly. To address such a need, we formulate in this paper two experimental metrics for coverage-based measurement of test redundancy in the context of JUnit test suites. We then evaluate the approach by measuring the redundancy of four real Java projects. The automated measures are compared with manual redundancy decisions (performed through an inspection by a tester). The results and lessons learned are interesting and somewhat surprising in that besides they show usefulness of coverage information, they present a set of shortcomings (in terms of precision) for ...