Function __setFsWatchForTests

src/sync/watcher.ts:140–142

(fn: WatchFn | null)

/** @internal Test-only seam to inject a fake fs.watch implementation. */
export function __setFsWatchForTests(fn: WatchFn | null): void {
  watchImpl = fn ?? fs.watch;
}

/**
 * Upper bound on simultaneously-watched directories on the Linux per-directory