Modifying a nested collection throws, whatever collection holds it

All 9 scenarios hold

A collection that a table passes to a test method is read-only. Adding to a List or a Set throws. Putting into a Map throws. Modifying any collection nested inside them throws. A row's data therefore stays as written, however the test method treats it.

Immutability reaches every level of a row's value, so a collection reached through another collection rejects modification too.