Write tests with jest (Coverage 100%)

[timhagn]

As written in the now closed #15, I updated the tests in regard to the changes made to this repo in the meantime. As the default values for the internal functions pxToEmOrRem() and getSizeFromBreakpoint were never used, I removed them. Now the tests are at 100% and I only added packages as devDependencies : ).

Is this now mergeable ; )?

Best,

Tim.

=============================== Coverage summary ===============================
Statements   : 100%
Branches     : 100%
Functions    : 100%
Lines        : 100%
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[timhagn]

Hola, is anybody out there % )?

[timhagn]

Hi there,

welcome to the collaborator club : ). Am in the suggestions - but keep in mind that I wrote this PR three quarts of a year ago ; ). Also, I'm quite booked at the moment, so don't know, when I will have time to change this.

Best,

Tim.