TST: Add a test for _build

[bashtage]

No description provided.

[codecov]

Codecov Report

❌ Patch coverage is 91.30435% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 99.63%. Comparing base (3307dfc) to head (a1ed0b7).
⚠️ Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
arch/tests/test_build.py	91.30%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #811      +/-   ##
==========================================
+ Coverage   99.54%   99.63%   +0.09%     
==========================================
  Files          75       76       +1     
  Lines       15237    15260      +23     
  Branches     1284     1284              
==========================================
+ Hits        15167    15204      +37     
+ Misses         42       23      -19     
- Partials       28       33       +5     

Flag	Coverage Δ
adder	99.59% <91.30%> (+0.09%)	⬆️
subtractor	99.59% <91.30%> (+0.09%)	⬆️

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