Comment 2 for bug 1835419

To clarify the issue here (I think most people reading this will already know but just for clarify), this is common behavior for "collection" style HTTP API responses. If the response is a list, a list with 0 members is a 200 response.

So as long as the identifier passed to GET /allocation/{identifier} is well-formed, you'll get back a list, because that identifier notionally identifies a group of allocations that may exist, but right now is empty.