test: improve coverage

[JustinBeckwith]

Just trying to push the code coverage up a little bit at a time.

[codecov-io]

Codecov Report

Merging #287 into master will increase coverage by 0.6%.
The diff coverage is n/a.

@@            Coverage Diff            @@
##           master     #287     +/-   ##
=========================================
+ Coverage   91.71%   92.31%   +0.6%     
=========================================
  Files          13       13             
  Lines         833      833             
  Branches      179      179             
=========================================
+ Hits          764      769      +5     
+ Misses         69       64      -5

Impacted Files	Coverage Δ
src/auth/googleauth.ts	86.17% <0%> (+0.92%)	⬆️
src/transporters.ts	95.74% <0%> (+6.38%)	⬆️

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