Generate test AppImage files

[azubieta]

As we keep adding tests new AppImage files will be required to test each scenario. Having all of them in the sources repository will just make our repository bigger and slower to clone. As most of such files can be generated using appimagetool we must just include the recipes and generate them while building the whole project.

[TheAssassin]

I think this library should not rely on actual files for tests, but instead test things unit wise with the minimum relevant amount of data for this purpose.

[azubieta]

Indeed we can test a wide range of features with the approach you propose. But in the end we will also have to test if on real files. Otherwise it would remain incomplete.

[TheAssassin]

Sure. But not to just see whether parsing a broken desktop file will return in a specific error...