Load this extension (if loading from an unsigned xpi, first go to about:config, and set xpinstall.signatures.required to false).
The extension has registered a webRequest listener that redirects all tested resource request to a web-accessible moz-extension URL.
This test does the following:
1. Visit example.com.
2. Load a script resource (visible in console of new tab).
3. Load a script resource.
4. Load a style resource (visible in document of new tab).
5. Load a style resource.
6. Load a frame resource (visible in document of new tab).
7. Load a frame resource.
When this extension is loaded in unpacked mode, every test succeeds in Firefox 56/57.
When this extension is installed from an xpi:
- step 3 fails (second script load)
- step 6 and 7 fail (subframe loads)