Fix verbose messages and add tests

[koheiw]

No description provided.

[codecov]

Codecov Report

❌ Patch coverage is 87.50000% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 86.70%. Comparing base (d115e4d) to head (6b4882a).
⚠️ Report is 3 commits behind head on master.

Files with missing lines	Patch %	Lines
src/wordvector.cpp	87.50%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master      #39      +/-   ##
==========================================
+ Coverage   84.20%   86.70%   +2.50%     
==========================================
  Files          16       16              
  Lines         785      790       +5     
==========================================
+ Hits          661      685      +24     
+ Misses        124      105      -19     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.