Refactor optimistic lock api and test

[Fs02]

• Update lockVersion query helper to internal api
• Reorder and rename test function

[codecov]

Codecov Report

Merging #276 (e051a9d) into master (f3a1b01) will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##            master      #276   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           33        33           
  Lines         2768      2768           
=========================================
  Hits          2768      2768           

Impacted Files	Coverage Δ
filter_query.go	100.00% <ø> (ø)
repository.go	100.00% <100.00%> (ø)

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