The previous test replaced _resolve_context_length itself with a fake that
re-did the threading, so it could not fail if the production call dropped the
kwarg; the sibling test only called get_model_context_length directly (green on
main, and its list-shaped `models` fixture is silently ignored by the config
loader). One test now patches agent.context_compressor.get_model_context_length
where production reads it and asserts the kwarg arrives; file moved next to the
other compressor tests. The defensive list copy is dropped (no caller mutates).
kshitijk4poor