Testing a plugin in different languages - how?



I’m trying to add a second language - French, initially - (and perhaps later, other languages) to the plugin Angular Dimension 2, recently published jointly with Steve Baumgartner. It works in English, and also correctly handles dot or comma as decimal separator. But I can’t see how to test whether the translations work, using the Language Handler.

I want (if possible) not to have to install a French version of SU, though I could if necessary.

I found this in an old thread on the subject of the Ruby Language Handler.

Does this apply on a Mac too? When I try on Mac El Capitan, in Terminal, the nearest equivalent I can find is:
open /Applications/SketchUp\ 2017/SketchUp\ Pro\ 2017.app --args -lang=fr

[EDIT} After a bit more googling, found this instead:

cd "/Applications/Sketchup 2017/Sketchup Pro 2017.app/Contents/MacOS"


./Sketchup -lang=fr

In either case, SU 2017 Pro starts, but the locale reported in the Ruby console by Sketchup.get_locale is still en-US, and the Language Handler still displays prompts in English, even though I have an appropriate set of .strings defined in Plugins/SLB_JWM_draw_angle_dim/Resources/fr folder and a dozen or so calls to the language handler, which was defined in the extension startup script as:

    # Constant for language strings swapping...
    DangLH = LanguageHandler.new('draw_angle_dim.strings')
    # patch for compatibility with old versions of SketchUp
    unless DangLH.respond_to? "[]"
      def DangLH.[](string)

I’m trying to test whether the translations work. I don’t want to have to install the French version of SU as well as English, just for testing. But do I have to? And set the locale to France and/or the language to French?

We also have two Web Dialogues defined and a JS file which passes data back and forth between web dialogue and Ruby. I’ve translated the HTML pages into French, along with associated JavaScript outputs where necessary.

What’s the best way to invoke the French pages when the locale is set to French? I’ve tested that they work, when I use the French versions to replace the English ones in the extension’s own main folder.

I can’t find anything much about this aspect of plugin/extension development either searching this forum, or by a general Google search.

Are there any examples you know of I could follow?