crosstesting

Cross-testing, sometimes written crosstesting, is a testing approach in which software, hardware, or systems are evaluated across multiple environments, configurations, versions, or implementations to verify interoperability, compatibility, and consistent behavior. The goal is to uncover environment-specific defects, regression risks, and discrepancies that may not appear when testing in a single setup.

Practices include building a test matrix that pairs combinations of platforms (operating systems, browser versions, device types), runtimes or APIs, and data sets. Teams run automated test suites in each cell, compare results to a reference implementation or baseline, and investigate any divergences. Results are tracked and used to drive fixes, updates, or compatibility adjustments. In standards and interoperability work, crosstesting often accompanies conformance testing to demonstrate that implementations meet a specification across contexts.

Common domains include web development with cross-browser testing, cross-platform software, APIs and cloud services, database engines, and embedded devices. The approach is supported by virtualization, containerization, cloud-based test farms, and continuous integration or continuous delivery pipelines to provision diverse environments and automate execution.

Challenges include maintaining a comprehensive matrix, dealing with flaky tests, coordinating data sets and test environments, and the overhead of keeping test suites in sync with evolving specifications and platforms.

Crosstesting is distinct from cross-validation in machine learning, though both share the idea of testing across multiple contexts.