  Realistic benchmarks of reproducible bugs and fixes are vital to good
experimental evaluation of debugging and testing approaches. However, there is
no suitable benchmark suite that can systematically evaluate the debugging and
testing methods of quantum programs until now. This paper proposes Bugs4Q, a
benchmark of thirty-six real, manually validated Qiskit bugs from four popular
Qiskit elements (Terra, Aer, Ignis, and Aqua), supplemented with the test cases
for reproducing buggy behaviors. Bugs4Q also provides interfaces for accessing
the buggy and fixed versions of the Qiskit programs and executing the
corresponding test cases, facilitating the reproducible empirical studies and
comparisons of Qiskit program debugging and testing tools. Bugs4Q is publicly
available at https://github.com/Z-928/Bugs4Q.
