There are a number of time-series files that are lacking good unit coverage. This ticket will look into adding more unit coverage where possible/appropriate. More information on the existing coverage files can be found by following this guide. Some files of interest include:

mongo/db/timeseries/timeseries_commands_conversion_helper.cpp

mongo/db/timeseries/bucket_catalog/bucket_catalog_server_status.cpp

mongo/db/timeseries/bucket_compression_failure.cpp

mongo/db/timeseries/timeseries_extended_range.cpp

mongo/db/timeseries/bucket_catalog/closed_bucket.cpp

mongo/db/timeseries/bucket_catalog/execution_stats.cpp

mongo/db/timeseries/timeseries_write_util.cpp

mongo/db/timeseries/timeseries_index_schema_conversion_functions.cpp

mongo/db/timeseries/timeseries_options.cpp

Failpoints to look at:

timeseriesDataIntegrityCheckFailureUpdate
hangTimeseriesDirectModificationBeforeWriteConflict
hangTimeseriesDirectModificationAfterStart
hangTimeseriesDirectModificationBeforeFinish
hangTimeseriesInsertBeforeReopeningBucket
runPostCommitDebugChecks
alwaysUseSameBucketCatalogStripe
hangTimeSeriesBatchPrepareWaitingForConflictingOperation
simulateBsonColumnCompressionDataLoss