The integration test for storage capabilities is comprised of three components:
storage_realm
/ \
memfs storage_user
The memfs and storage_user components are pretty simple. memfs runs memfs, a mutable in-memory filesystem, and makes it available on its outgoing directory at the path /minfs. storage_user will forward any open connections to /data on its outgoing directory to /data in its namespace.
The manifest for storage_realm connect memfs and storage_user together, creating storage capabilities from memfs's exposed directory and offering them to storage_user. This allows storage_realm to both access the memfs instance directly, and to access it through storage_user's exposed /data directory.
With this set up, the storage_realm component binds to storage_user and writes a file to the /data directory, and then binds to memfs and attempts to read the file back from the sub-directory that should have been generated for the storage capability used by storage_user.