Turn digests back on in test environment

[jon-kirwan]

What

https://trello.com/c/fc41oyEK/1923-enable-individual-loading-of-stylesheets-in-government-frontend.

Turn digests back on (remove config.assets.digest = false) in test environment as a pre-requisite to implementing the AssetHelper to load component and view style sheets only required on the page being viewed.

Why

The default config.assets.digest was changed here: a806be8 due to an issue loading Axe core in integration tests (with a comment to re-enable the option).

I've discovered an issue running some tests when individual style sheets are loaded with the GOV.UK Publishing Components AssetHelper module.

test_guides_with_no_parts_in_a_step_by_step_with_hide_chapter_navigation_do_not_error
ERROR (4.82s)
Minitest::UnexpectedError: ActionController::RoutingError: No route matches [GET] 
"/govuk_publishing_components/components/_step-by-step-nav-related.css"

• The issue only affects _step-by-step-nav-related.css. All other CSS files are loaded correctly
• When digests are disabled _step-by-step-nav-related.css seems to be incorrectly identified as having a digest as documented here: Some assets don't get delivered anymore after update to 4.1.1 because of funky name conflict (dashes make them look like digest for the Regexp) rails/sprockets#749
• The suffix -related is stripped from the stylesheet path, which seems to cause an issue with step-by-step-nav.css.
• It only seems to happen when you have more than two style sheets with the same name and one has a suffix e.g.

@import "components/step-by-step-nav-related";
@import "components/step-by-step-nav";

• The error only occurs when that suffix is 7 or more characters (you do not see this with _attachment-link.css).

With digests re-enabled I've seen no issues running component guide accessibility tests locally -

Notice

Banner

Visual changes

None.

[MartinJJones]

Changes look good to me 👍