Merge pull request #2 from jlucasps/master

Testes com chai.js
Merge pull request #3 from jlucasps/master

Adiciona info sobre mocha e buster
Merge pull request #4 from jlucasps/master

Código usando clock e stubs
Fix typo
Adjust slides on presentation
Fix indentation
Using call(thisArg) to call nextSong
Explain why use stub and fake clock
Explains why/when use spyes
Q&A and last slide