Load local file (HTML)?

I have read the documentation which specifies I need to enable:
```
withLocalStorage: true,
withLocalUrl: true,
allowFileURLs: true,
```
and `localUrlScope` for iOS.

But I cannot figure out where to place the html file, and how to load it with the `url:`

I tried:
`url: 'file:///assets/test.html',`

But that did not work?