Running loki screenshot tests with Storybook for multiple themes

[jkayen]

Is there an easy way to run all stories with loki when there are multiple themes in a design system, without writing double the stories in with each theme mannualy?

[cameron-yee]

@jkayen Did you find a good approach for this?

We got around this by:

1. Wrap every story in a theme decorator
2. Build storybook for each theme (build-storybook -o ./public/storybook/{THEME})
3. Test with Loki for each Storybook build using these options:

• --reactUri: ./public/storybook/{THEME}/storybook-static
• --output: ./.loki/{THEME}/current
• --reference: ./.loki/{THEME}/reference
• --difference: ./.loki/{THEME}/difference

This works well, but it'd be nice if it could be handled in loki.config.js somehow instead.