X_TEST_ISLAND_STATES_MISSING_FILE
Means
an island state manifest names an island that is not on disk
Typical cause
assertIslandFiles(manifests, root) found no file at the declared island. The state list IS the expected screenshot set, so a manifest pointing at a moved file expands to pictures that can never be taken
Fix
set island: to the path that exists — it is relative to the app root, not to the states file