Editor’s notes: This article provides a comprehensive survey of functional testing and validation methodologies for quantum circuits, bridging classical testing concepts with their quantum counterparts. Covering techniques ranging from coverage analysis and assertions to formal verification, mutation testing, metamorphic testing, and differential testing, the survey highlights the unique challenges introduced by quantum mechanics and noisy quantum hardware. By organizing and assessing the state of the art, the authors establish a valuable reference for researchers and practitioners seeking to improve the correctness, robustness, and reliability of quantum software. —Robert Wille, Technical University of Munich, Germany