Extensible Testing for Infrastructure as Code

Developers automate deployments with Programming Languages Infrastructure as Code (PL-IaC) by implementing IaC programs in popular languages like TypeScript and Python. Yet, systematic testing---well established for high-velocity software development---is rarely applied to IaC programs because IaC testing techniques are either slow or require extensive development effort. To solve this dilemma, we develop ProTI, a novel IaC unit testing approach, and implement it for Pulumi TypeScript. Our preliminary experiments with simple type-based test case generators and oracles show that ProTI can find bugs reliably in a short time, often without writing any additional testing code. ProTI's extensible plugin architecture allows combining, adopting, and experimenting with new approaches, opening the discussion about novel generators and oracles for efficient IaC testing.