Write tests for cdb.InsertWorkflowExecutionWithTasks

[taylanisikdemir]

What changed?

InsertWorkflowExecutionWithTasks had 0 test coverage. It calls bunch of other helper functions which are recently covered by tests in workflow_utils_test.go. This PR covers InsertWorkflowExecutionWithTasks without going too deep.

Misc change: Some of the helper functions had error returns in the signature but always return nil. Updated signature and callers.

Why?
Increase coverage.

[coveralls]

Pull Request Test Coverage Report for Build 018dd436-ad2f-4733-b6d9-7c350ce72b46

Details

• -2 of 16 (87.5%) changed or added relevant lines in 2 files are covered.
• 39 unchanged lines in 10 files lost coverage.
• Overall coverage increased (+0.006%) to 62.86%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
common/persistence/nosql/nosqlplugin/cassandra/workflow.go	10	12	83.33%

Files with Coverage Reduction	New Missed Lines	%
common/peerprovider/ringpopprovider/config.go	2	81.58%
common/task/weighted_round_robin_task_scheduler.go	2	89.05%
service/frontend/api/handler.go	2	62.05%
service/history/execution/mutable_state_util.go	2	37.63%
service/history/task/transfer_active_task_executor.go	2	72.38%
service/history/task/transfer_standby_task_executor.go	2	87.01%
service/matching/taskListManager.go	2	80.46%
common/archiver/filestore/historyArchiver.go	4	80.95%
service/frontend/wrappers/metered/metered.go	9	62.02%
common/persistence/sql/workflowStateMaps.go	12	82.97%

Totals
Change from base Build 018dd39f-cad6-4614-851d-0823a418fc57:	0.006%
Covered Lines:	92893
Relevant Lines:	147777

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💛 - Coveralls