Write tests for cdb (Cassandra DB wrapper) basic functions

[taylanisikdemir]

What changed?

Adding tests for common/persistence/nosql/nosqlplugin/cassandra/db.go

Why?
Increase coverage

[coveralls]

Pull Request Test Coverage Report for Build 018dd2c4-d5dc-4f4a-8089-0d0290881cd5

Details

• 0 of 14 (100.0%) changed or added relevant lines in 1 file are covered.
• 60 unchanged lines in 16 files lost coverage.
• Overall coverage increased (+0.03%) to 62.773%

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Files with Coverage Reduction	New Missed Lines	%
common/peerprovider/ringpopprovider/config.go	2	81.58%
common/persistence/sql/common.go	2	72.73%
common/persistence/sql/sqlplugin/postgres/db.go	2	85.0%
common/persistence/sql/sqlplugin/postgres/task.go	2	73.4%
common/task/weighted_round_robin_task_scheduler.go	2	89.05%
service/frontend/api/handler.go	2	62.05%
service/history/task/fetcher.go	2	85.57%
service/history/task/transfer_standby_task_executor.go	2	86.6%
service/matching/db.go	2	73.23%
common/log/tag/tags.go	3	50.18%

Totals
Change from base Build 018dd233-35a0-491a-a1ed-ac3dde904d76:	0.03%
Covered Lines:	92787
Relevant Lines:	147813

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💛 - Coveralls