Wraps Optimizely Feature Experimentation SDK testing patterns - client init from a fixture datafile (offline-friendly), the decide / decideAll v5 API, forced-decisions for per-test arm pinning (fixing which variation a user gets), OptimizelyUserContext + activate/track events, assignment-integrity (deterministic bucketing) tests. Use when writing A/B tests or feature-flag tests for Optimizely-instrumented application code. For another experimentation SDK use the matching harness - statsig-test, vwo-test, amplitude-experiment-test, or split-io-test; for experiment DESIGN gates not SDK code use ab-test-validity-checklist.