Context-Aware Unit Testing for Quantum Subroutines

TL;DR

This paper proposes a context-aware approach to unit testing quantum subroutines, addressing quantum-specific challenges with probabilistic assertions and demonstrating its application on quantum algorithms.

Contribution

It introduces a novel framework for quantum unit testing that incorporates context-awareness to improve efficiency and accuracy.

Findings

Effective unit testing of quantum subroutines demonstrated on a three-qubit GHZ state preparation.

Applied framework to subroutines within Shor's algorithm, showing practical feasibility.

Trade-offs between accuracy, coverage, and efficiency analyzed.

Abstract

Software testing is a critical component of the classical software development lifecycle, and this principle is expected to hold true for quantum software as it evolves toward large-scale production and adherence to industry standards. Developing and testing quantum software presents unique challenges due to the non-deterministic nature of quantum information, the high dimensionality of the underlying Hilbert space, complex hardware noise, and the inherent non-local properties of quantum systems. In this work, we model quantum subroutines as parametrized quantum channels and explore the feasibility of creating practical unit tests using probabilistic assertions, combined with either quantum tomography or statistical tests. To address the computational complexity associated with unit testing in quantum systems, we propose incorporating context-awareness into the testing process. The trade-offs between accuracy, state space coverage, and efficiency associated with the proposed theoretical framework for quantum unit testing have been demonstrated through its application to a simple three-qubit quantum subroutine that prepares a Greenberger-Horne-Zeilinger state, as well as to subroutines within a program implementing Shor's algorithm.