Redmine

• Use MySQL
• Time zone data is loaded(If it is not loaded, time zone conversion will fail.)
• Change user language from UTC to something else
• Group by created_on at issues/index

query.result_count_by_group executed in QueriesHelper#grouped_query_results returns the following result.

Actual result:

{2006-07-18 14:00:00 +0000=>2,
 2019-08-13 14:00:00 +0000=>1,
 2019-08-18 14:00:00 +0000=>1,
 2019-08-23 14:00:00 +0000=>2,
 2019-08-25 14:00:00 +0000=>1,
 2019-08-28 14:00:00 +0000=>3}

Expected result:

 {Wed, 19 Jul 2006=>2,
 Tue, 13 Aug 2019=>1,
 Sun, 18 Aug 2019=>1,
 Fri, 23 Aug 2019=>2,
 Sun, 25 Aug 2019=>1,
 Wed, 28 Aug 2019=>3}

The number of records cannot be retrieved properly because the keys format is different than expected.

This issue is related to #13803.