Fix rendering of unnumbered papers

The "false" check in the unnumbered command and act papers was failing
because the component is passed an empty string rather than nil for the
number, which does not evaluate to false:

e.g.

a = false
!a
=> true
b = nil
!b
=> true
c = ""
!c
=> false

Therefore the check was returning `nil` rather than the "Unnumbered..."
text.

CHANGELOG.md

@@ -9,6 +9,7 @@
 
 ## Unreleased
 
+* Fix rendering of unnumbered papers ([PR #3988](https://github.com/alphagov/govuk_publishing_components/pull/3988))
 * Add PDF specific icon to attachment component ([PR #3985](https://github.com/alphagov/govuk_publishing_components/pull/3985))
 * Add the hidden attribute to mobile menu button ([PR #3975](https://github.com/alphagov/govuk_publishing_components/pull/3975))
 * Add tool_name to GA4 feedback component tracking ([PR #3984](https://github.com/alphagov/govuk_publishing_components/pull/3984))

lib/govuk_publishing_components/presenters/attachment_helper.rb

@@ -78,8 +78,8 @@ def reference
       end
 
       def unnumbered_reference
-        unnumbered_reference = "Unnumbered command paper" if attachment_data[:unnumbered_command_paper].eql?(true) && !attachment_data[:command_paper_number]
-        unnumbered_reference = "Unnumbered act paper" if attachment_data[:unnumbered_hoc_paper].eql?(true) && !attachment_data[:hoc_paper_number]
+        unnumbered_reference = "Unnumbered command paper" if attachment_data[:unnumbered_command_paper].eql?(true) && attachment_data[:command_paper_number].blank?
+        unnumbered_reference = "Unnumbered act paper" if attachment_data[:unnumbered_hoc_paper].eql?(true) && attachment_data[:hoc_paper_number].blank?
         unnumbered_reference
       end
 

spec/lib/govuk_publishing_components/presenters/attachment_spec.rb

@@ -175,6 +175,7 @@
         title: "test",
         url: "test",
         content_type: "text/csv",
+        command_paper_number: "",
         unnumbered_command_paper: true,
       )
       expect(attachment.unnumbered_reference).to eq("Unnumbered command paper")
@@ -185,6 +186,7 @@
         title: "test",
         url: "test",
         content_type: "text/csv",
+        hoc_paper_number: "",
         unnumbered_hoc_paper: true,
       )
       expect(attachment.unnumbered_reference).to eq("Unnumbered act paper")