test: dictzip test

[ianlewis]

Description:

Add tests for dictzip files.

Related Issues:

N/A

Checklist:

• Review the CONTRIBUTING.md documentation.
• Add a reference to a related issue in the repository.
• Add a description of the changes proposed in the pull request.
• Add unit tests if applicable.
• Update documentation if applicable.
• Add a note in the CHANGELOG.md if applicable.
• Sign the Google CLA.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 14.03509% with 49 lines in your changes missing coverage. Please review.

Project coverage is 40.00%. Comparing base (2d79407) to head (f8ec0d0).

Files with missing lines	Patch %	Lines
internal/testutil/dict.go	7.54%	49 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #32      +/-   ##
==========================================
- Coverage   41.89%   40.00%   -1.90%     
==========================================
  Files          11       11              
  Lines         685      735      +50     
==========================================
+ Hits          287      294       +7     
- Misses        361      405      +44     
+ Partials       37       36       -1     

Files with missing lines	Coverage Δ
dict/dict.go	79.41% <100.00%> (+4.22%)	⬆️
idx/idx.go	47.74% <100.00%> (ø)
internal/testutil/dict.go	14.77% <7.54%> (-14.96%)	⬇️