tests: Reformat tests, evaluate status in addition to I/O

Previously we only compared output, we now evaluate
status as well.

For example test {} => {} was misleading since the reason
it roundtripped was because it is *invalid* and we replace
invalid blobs with an empty object in blob storage.

But in the API this'll never get used because getStatus
will have a fatal error in it. Which overrides the data.
The tests were previously looking in the data whilst ignoring
the return status.

Change-Id: I9809f126c1615c9bc9c28ce2d8bb7953058cbf6e
Implement Sets

Change-Id: I93a0ba7287fec6e5566994d03dff1d8eaeeb8430