Create test folder with a demo html page + webpack config

[malinbranduse]

This could be useful for contributors to test any changes (manually for now) inside the repo, not having to use an external environment. This folder should be in .npmignore.

Automated testing I think is out of the scope of this project since it's more of a wrapper plugin for Browsersync. Perhaps some unit tests for the css emissions check?

[Va1]

test/demo folder is nice idea! i might work on this in near future.

i am not sure of how can this be unit-tested though

[malinbranduse]

@Va1 It's fine, I think I'll do it, just wrote it down as an issue so we won't forget 😁 About unit testing, I've seen some other plugins do tests, even intergration tests directly running webpack so it might be possible, but I have to do some deeper checks.

[Va1]

@malinushj yeah, i did tests for webpack stuff as part of other package developed by me. but i am not sure i understand what we can cover in this package