refactor: test structure and style guide doc

[Hotell]

Current behavior

Currently we are testing Skate class if it has rendered like this

it( `should render`, () => {
 return mount( <Button /> ).wait(( element ) => {}
}

neither me and @elmariofredo remember why we use it that way, because we are using intrinsic element.

Expected behavior

We should review with whole team and change it accordingly and also update the docs.