Make tests about dependencies independent from the order of planned messages
Remove needless too many input
Check the metadata of broadcasted message
Extract test of errors reducer and gatherer to another class
Don't output duplicated information
Simplify
Simplify search gatherer
Don't output needless information
Simplify.

The old implementation was too robust.
Don't output needless output-limit
Don't override output-offset if we don't have to override it
Use more meaningful name
Migrate a test for output-limit
Define expected gatherer from scratch.

Because it is not related to the output parameter of the query.
Migrate test for output-records
Align
Don't break the given queries
Add trailing comma to the last item of a hash
Add missing test for reducer
Migrate test for output-offset