add exception testing

[ezbz]

No description provided.

[codecov]

Codecov Report

Merging #84 (cef6c0d) into master (6849af2) will increase coverage by 0.54%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master      #84      +/-   ##
==========================================
+ Coverage   97.83%   98.37%   +0.54%     
==========================================
  Files          10       10              
  Lines         370      370              
==========================================
+ Hits          362      364       +2     
+ Misses          8        6       -2     

Impacted Files	Coverage Δ
gitlabber/git.py	95.31% <0.00%> (+3.12%)	⬆️

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