CSI volumes are namespaced. But the client does not include the namespace in the
staging mount path. This causes CSI volumes with the same volume ID but
different namespace to collide if they happen to be placed on the same host. The
per-allocation paths don't need to be namespaced, because an allocation can only
mount volumes from its job's own namespace.
Rework the CSI hook tests to have more fine-grained control over the mock
on-disk state. Add tests covering upgrades from staging paths missing
namespaces.
Fixes: https://github.com/hashicorp/nomad/issues/18741
and MockCSIManager to support the call counting
that csi_hook_test expects
instead of implementing csimanager
interfaces in two separate places:
* client/allocrunner/csi_hook_test
* client/csi_endpoint_test
they can both use the same mocks defined in
client/pluginmanager/csimanager/
alongside the actual implementations of them.
also refactor TestCSINode_DetachVolume
to use use it like Node_ExpandVolume
so we can also test the happy path there
