improve rule testing output

[j8-redis]

improved output includes the name of the test

test ./tests/shard_instance.yml SUCCESS
test ./tests/latency_warning.yml SUCCESS
test ./tests/no_requests.yml SUCCESS

[jeremyplichta]

Thanks @j8-redis - how often do these tests run? Can we have them run as part of a gitaction?

[j8-redis]

Thanks @j8-redis - how often do these tests run? Can we have them run as part of a gitaction?

They run on demand, and they require the Prometheus promtool application. The rules don't change very often; they're provided to assist clients when they make changes to the rules.