Proposal

Related to grafana/mimir#11573 where someone is adding a pure native histogram.

Currently (June 2025) there's no text representation implemented for native histograms so one cannot use the GatherAndCompare from the testutil package to assert on: existence and value of native histograms.

The text format for native histograms - as proposed currently - isn't straightforward for developers to assert on. Doesn't have buckets, rather it has spans and deltas and such.

A solution is needed to be able to:

• check that a native histogram was gathered
• check the count
• check the sum
• check that it has expected number of observations in an interval