Adding more tests

[asadm]

I have tests set up for most of basic scenarios. It would be great if someone could set up headless chrome (puppeteer maybe) and test HMR, Parcel generated builds, file watcher, npm installation, etc.

[Naaman-Saif]

I can look into Puppeteer Tests

[asadm]

@Naaman-Saif
That would be great. I have added basic HMR tests without puppeteer here. It currently fetches SSR page again to see if zero sent the changed page. Adding puppeteer will actually test HMR (apply changes without browser reload).