Add the keyboard shim for link buttons

CHANGELOG.md

@@ -7,6 +7,9 @@
   useful summary for people upgrading their application, not a replication
   of the commit log.
 
+## Unreleased
+* Add the keyboard shim for link buttons ([PR #3027](https://github.com/alphagov/govuk_publishing_components/pull/3027))
+
 ## 32.1.0
 
 * Calculate viewport width correctly for navbar in Chrome and Firefox when Mac scrollbars are enabled ([PR #3016](https://github.com/alphagov/govuk_publishing_components/pull/3016))

lib/govuk_publishing_components/presenters/button_helper.rb

@@ -37,6 +37,10 @@ def initialize(local_assigns)
         end
         @rel = local_assigns[:rel]
         @data_attributes = local_assigns[:data_attributes]
+        if href.present?
+          @data_attributes ||= {}
+          @data_attributes[:module] = ["govuk-button", @data_attributes[:module]].reject(&:blank?).join(" ")
+        end
         @margin_bottom = local_assigns[:margin_bottom]
         @inline_layout = local_assigns[:inline_layout]
         @target = local_assigns[:target]

spec/components/button_spec.rb

@@ -27,7 +27,7 @@ def component_name
     assert_select ".govuk-button[type=submit]", text: "Submit"
 
     render_component(text: "Link", href: "#", type: "button")
-    assert_select "a.govuk-button", text: "Link"
+    assert_select "a.govuk-button[data-module=\"govuk-button\"]", text: "Link"
     assert_select "a.govuk-button[type=submit]", false
 
     render_component(text: "Button", type: "button")
@@ -169,7 +169,7 @@ def component_name
       },
     )
 
-    assert_select "a.govuk-button[data-module='cross-domain-tracking']"
+    assert_select "a.govuk-button[data-module='govuk-button cross-domain-tracking']"
     assert_select "a.govuk-button[data-tracking-code='GA-123ABC']"
     assert_select "a.govuk-button[data-tracking-name='transactionTracker']"
   end