Wraps Statsig SDK testing patterns - server-side statsig.initialize with an API key, gate / experiment / dynamic-config evaluation (checkGate, getExperiment, getConfig), local-evaluation offline mode, overrideGate / overrideConfig to force a user into an arm, assignment-integrity tests. Use when writing tests for Statsig-instrumented application code. For another experimentation SDK use the matching harness - optimizely-test, vwo-test, amplitude-experiment-test, or split-io-test; for experiment DESIGN gates not SDK code use ab-test-validity-checklist.