Write more tests for cassandra/domain.go

[taylanisikdemir]

What changed?
Adding more tests to cassandra/domain.go

Why?
Improve coverage.

[codecov]

Codecov Report

Merging #5867 (12684ae) into master (8fc9382) will decrease coverage by 0.09%.
The diff coverage is 100.00%.

❗ Current head 12684ae differs from pull request most recent head ee2d3da. Consider uploading reports for the commit ee2d3da to get more accurate results

Additional details and impacted files

Files	Coverage Δ
.../persistence/nosql/nosqlplugin/cassandra/domain.go	98.85% <100.00%> (+60.85%)	⬆️

... and 9 files with indirect coverage changes

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[coveralls]

Pull Request Test Coverage Report for Build 018eac31-c4cd-404e-b346-ae1524af6b92

Details

• 2 of 2 (100.0%) changed or added relevant lines in 1 file are covered.
• 56 unchanged lines in 9 files lost coverage.
• Overall coverage increased (+0.04%) to 66.514%

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Files with Coverage Reduction	New Missed Lines	%
service/matching/matcher.go	1	91.07%
service/matching/taskReader.go	2	84.88%
common/task/fifo_task_scheduler.go	2	82.47%
common/util.go	2	91.78%
common/persistence/historyManager.go	2	66.67%
service/history/queue/timer_queue_processor_base.go	3	77.82%
service/history/task/transfer_standby_task_executor.go	4	86.19%
service/history/task/fetcher.go	4	86.08%
service/history/execution/mutable_state_task_refresher.go	36	62.03%

Totals
Change from base Build 018eabfc-0f71-4bcd-8f78-10ed5dda57ef:	0.04%
Covered Lines:	97337
Relevant Lines:	146341

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💛 - Coveralls