Add ActionText::FixtureSet.attachment

Permit generating rich-text attachment markup in YAML fixtures:

    hello_world_review_content:
      record: hello_world (Review)
      name: content
      body: <p><%= ActionText::FixtureSet.attachment("messages", :hello_world) %> is great!</p>

actiontext/CHANGELOG.md

@@ -1,3 +1,16 @@
+*   Declare `ActionText::FixtureSet.attachment` to generate an
+    `<action-text-attachment sgid="..."></action-text-attachment>` element with
+    a valid `sgid` attribute.
+
+    ```ruby
+    hello_world_review_content:
+      record: hello_world (Review)
+      name: content
+      body: <p><%= ActionText::FixtureSet.attachment("messages", :hello_world) %> is great!</p>
+    ```
+
+    *Sean Doyle*
+
 *   Locate `fill_in_rich_text_area` by `<label>` text
 
     In addition to searching for `<trix-editor>` elements with the appropriate

actiontext/lib/action_text.rb

@@ -14,6 +14,7 @@ module ActionText
   autoload :Attribute
   autoload :Content
   autoload :Fragment
+  autoload :FixtureSet
   autoload :HtmlConversion
   autoload :PlainTextConversion
   autoload :Rendering

actiontext/lib/action_text/fixture_set.rb

@@ -0,0 +1,12 @@
+# frozen_string_literal: true
+
+module ActionText
+  class FixtureSet
+    def self.attachment(fixture_set_name, label, column_type: :integer)
+      signed_global_id = ActiveRecord::FixtureSet.signed_global_id fixture_set_name, label,
+        column_type: column_type, for: ActionText::Attachable::LOCATOR_NAME
+
+      %(<action-text-attachment sgid="#{signed_global_id}"></action-text-attachment>)
+    end
+  end
+end

actiontext/test/fixtures/action_text/rich_texts.yml

@@ -0,0 +1,4 @@
+hello_world_review_content:
+  record: hello_world (Review)
+  name: content
+  body: <p><%= ActionText::FixtureSet.attachment("messages", :hello_world) %> is great!</p>

actiontext/test/fixtures/messages.yml

@@ -0,0 +1,2 @@
+hello_world:
+  subject: "A greeting"

actiontext/test/fixtures/reviews.yml

@@ -0,0 +1,3 @@
+hello_world:
+  message: $LABEL
+  author_name: "Ruby"

actiontext/test/unit/fixture_set_test.rb

@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+require "test_helper"
+
+class ActionText::FixtureSetTest < ActiveSupport::TestCase
+  def test_action_text_attachment
+    message = messages(:hello_world)
+    review = reviews(:hello_world)
+
+    attachments = review.content.body.attachments
+
+    assert_includes attachments.map(&:attachable), message
+  end
+end

activerecord/lib/active_record/fixtures.rb

@@ -585,6 +585,14 @@ module ActiveRecord
         end
       end
 
+      def signed_global_id(fixture_set_name, label, column_type: :integer, **options)
+        identifier = identify(label, column_type)
+        model_name = default_fixture_model_name(fixture_set_name)
+        uri = URI::GID.build([GlobalID.app, model_name, identifier, {}])
+
+        SignedGlobalID.new(uri, **options)
+      end
+
       # Superclass for the evaluation contexts used by ERB fixtures.
       def context_class
         @context_class ||= Class.new

guides/source/6_1_release_notes.md

@@ -402,6 +402,10 @@ Please refer to the [Changelog][action-text] for detailed changes.
     editor and fill it with given HTML content.
     ([Pull Request](https://github.com/rails/rails/pull/35885))
 
+*   Add `ActionText::FixtureSet.attachment` to generate
+    `<action-text-attachment>` elements in database fixtures.
+    ([Pull Request](https://github.com/rails/rails/pull/40289))
+
 Action Mailbox
 ----------