testing Directory Reference

Files
	backend_conformance.hpp
	The scripted cases every IViewBackend must pass, and the probe a backend author implements to run them.
	memory_history.hpp
	MemoryHistory: an IHistory held in memory, which a test moves through as a user moves through a browser's history.
	recording_backend.hpp
	morph::ui::testing::RecordingBackend: a headless widget tree with an operation log, a golden dump and user-interaction helpers — the test double and the reference for every real backend.