Fix documented return type of metadata_provider_add.
As the in-mem storage was written based on this documentation, fix it as well.
Add a test for this behavior.
Depends on !133 (closed).
Migrated from D717 (view on Phabricator)
As the in-mem storage was written based on this documentation, fix it as well.
Add a test for this behavior.
Depends on !133 (closed).
Migrated from D717 (view on Phabricator)