Closed-data agreement is validated against irrCAC. The checked-in JSON fixtures under tests/fixtures/ are generated by tests/tools/regen_oracle.R and then consumed by C++ golden tests. Continuous integration does not call R to regenerate oracle values.
For a fixture with oracle value \(\kappa^\star\) and C++ estimate \(\widehat\kappa\), golden tests assert
\[ |\widehat\kappa - \kappa^\star| \le \epsilon, \]
with a documented tolerance chosen for floating-point and convention differences. The purpose is parity for complete-data agreement conventions, not a simulation proof of missing-data behavior.
The R package is intentionally a thin Rcpp layer over the C++ library. R-level tests therefore focus on input conversion, exported object shape, S3 methods, dataset examples, and parity with a frozen irrCAC oracle (estimates and variances committed as literals, no external package required).
The legacy implementation (deleted from the tree on 2026-06-02, recoverable from git history at 6b30f98) is a math reference only. New estimators should be rewritten on Eigen and Result<T>, then tested against both C++ unit expectations and R-facing parity checks where practical.