test: fill gaps in library root

[nikoksr]

Description

Add some tests to fill in the gaps in the project root.

Motivation and Context

Gaps uncovered by codecov action.

How Has This Been Tested?

Ran test suite.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation (no code change)
• Refactor (refactoring production code)
• Other: Tests

Checklist:

• My code follows the code style of this project.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing tests passed.

[codecov-commenter]

Codecov Report

Merging #260 (0dac5dc) into main (23b572d) will increase coverage by 1.92%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main     #260      +/-   ##
==========================================
+ Coverage   49.46%   51.39%   +1.92%     
==========================================
  Files          12       12              
  Lines         467      467              
==========================================
+ Hits          231      240       +9     
+ Misses        215      208       -7     
+ Partials       21       19       -2     

Impacted Files	Coverage Δ
use.go	100.00% <0.00%> (+16.66%)	⬆️
send.go	100.00% <0.00%> (+29.16%)	⬆️

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