test: use Node.js mock instead of esmock package

[Dafyh]

#444

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 83.60%. Comparing base (28ee6a9) to head (03eb65d).
Report is 179 commits behind head on master.

Additional details and impacted files

@@             Coverage Diff              @@
##            master     #488       +/-   ##
============================================
- Coverage   100.00%   83.60%   -16.40%     
============================================
  Files           15       29       +14     
  Lines          649     1952     +1303     
  Branches         0        1        +1     
============================================
+ Hits           649     1632      +983     
- Misses           0      320      +320     

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[fraxken]

Hmm not sure why but one test is failing on ubuntu

[Dafyh]

I've searched but I can't find it. Indeed on ubuntu, the mock doesn't work inside the 'open' package ¯\(ツ)/¯.
The only way I've found is to put 'open' in an exported object 😑.

[fraxken]

@allcontributors please add @Dafyh for test

[allcontributors]

@fraxken

I've put up a pull request to add @Dafyh! 🎉