The same AST sweep over specs found fixtures maintained in parallel
across suites that have no reason to know about each other.
Twenty-one specs each mounted useMessageStream themselves and ten of the
harnesses were byte-identical; twenty now take renderMessageStream, with
overrides for the seams that genuinely vary. The SessionInfo builder was
spelled out field-by-field in seven specs, so a new backend field broke
seven files instead of one. Twenty specs carried their own inert
ResizeObserver and eleven repeated the animation-frame, CSS.escape,
scrollTo and WAAPI stubs the transcript needs to mount at all — split by
scope into src/test/jsdom for what any component might need and the
assistant-ui folder's own kit for the transcript. Plus the window-state
bridge, deferred, the external-store thread runtime, the manual
createRoot harness, and the per-folder caret, env-var, provider and
session fixtures.
Left alone on purpose: the store suites' makePrimary, where the vi.mock
harness around it is the actual duplication and cannot be hoisted out of
a hoisted factory; electron's deferred, where reaching into src/ from
the main process would invert the layering for eight lines; and the two
suites that compose another hook alongside the stream.
Brooklyn Nicholson
808fde106d