Fix delta histogram sum not being reset on collection by pichlermarc · Pull Request #2533

Fix delta histogram sum not being reset on collection by pichlermarc · Pull Request #2533 · open-telemetry/opentelemetry-python

Description

This PR fixes an issue where _ExplicitBucketHistogramAggregation does not reset the _sum field on collection, even though it always creates an AggregationTemporality.DELTA histogram and resets _bucket_counts to an all-zero array. This caused sum values to be wrong on export for both AggregationTemporality.DELTA and AggregationTemporality.CUMULATIVE

Fixes #2532

Type of change

Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

Added missing assertions to unit test.

Checklist:

Followed the style guidelines of this project
Changelogs have been updated
Unit tests have been added
Documentation has been updated