3 files changed, 22 insertions, 13 deletions
diff --git a/actiontext/CHANGELOG.md b/actiontext/CHANGELOG.md
index 9a314db75c..d28799279f 100644
--- a/actiontext/CHANGELOG.md
+++ b/actiontext/CHANGELOG.md
@@ -1,21 +1,21 @@
-*  The `fill_in_rich_text_area` system test helper locates a Trix editor and fills it in with the given HTML:
+*   The `fill_in_rich_text_area` system test helper locates a Trix editor and fills it in with the given HTML:
 
-   ```ruby
-   # <trix-editor id="message_content" ...></trix-editor>
-   fill_in_rich_text_area "message_content", with: "Hello <em>world!</em>"
+    ```ruby
+    # <trix-editor id="message_content" ...></trix-editor>
+    fill_in_rich_text_area "message_content", with: "Hello <em>world!</em>"
 
-   # <trix-editor placeholder="Your message here" ...></trix-editor>
-   fill_in_rich_text_area "Your message here", with: "Hello <em>world!</em>"
+    # <trix-editor placeholder="Your message here" ...></trix-editor>
+    fill_in_rich_text_area "Your message here", with: "Hello <em>world!</em>"
 
-   # <trix-editor aria-label="Message content" ...></trix-editor>
-   fill_in_rich_text_area "Message content", with: "Hello <em>world!</em>"
+    # <trix-editor aria-label="Message content" ...></trix-editor>
+    fill_in_rich_text_area "Message content", with: "Hello <em>world!</em>"
 
-   # <input id="trix_input_1" name="message[content]" type="hidden">
-   # <trix-editor input="trix_input_1"></trix-editor>
-   fill_in_rich_text_area "message[content]", with: "Hello <em>world!</em>"
-   ```
+    # <input id="trix_input_1" name="message[content]" type="hidden">
+    # <trix-editor input="trix_input_1"></trix-editor>
+    fill_in_rich_text_area "message[content]", with: "Hello <em>world!</em>"
+    ```
 
-   *George Claghorn*
+    *George Claghorn*
 
 
 Please check [6-0-stable](https://github.com/rails/rails/blob/6-0-stable/actiontext/CHANGELOG.md) for previous changes.
diff --git a/actiontext/lib/action_text/engine.rb b/actiontext/lib/action_text/engine.rb
index 0c2aebfd08..0f55d460a1 100644
--- a/actiontext/lib/action_text/engine.rb
+++ b/actiontext/lib/action_text/engine.rb
@@ -25,6 +25,10 @@ module ActionText
         def previewable_attachable?
           representable?
         end
+
+        def attachable_plain_text_representation(caption = nil)
+          "[#{caption || filename}]"
+        end
       end
     end
 
diff --git a/actiontext/test/unit/attachment_test.rb b/actiontext/test/unit/attachment_test.rb
index 026078dcec..54831a0271 100644
--- a/actiontext/test/unit/attachment_test.rb
+++ b/actiontext/test/unit/attachment_test.rb
@@ -50,6 +50,11 @@ class ActionText::AttachmentTest < ActiveSupport::TestCase
     assert_not_nil trix_attachment.attributes["content"]
   end
 
+  test "converts to plain text" do
+    assert_equal "[Vroom vroom]", ActionText::Attachment.from_attachable(attachable, caption: "Vroom vroom").to_plain_text
+    assert_equal "[racecar.jpg]", ActionText::Attachment.from_attachable(attachable).to_plain_text
+  end
+
   test "defaults trix partial to model partial" do
     attachable = Page.create! title: "Homepage"
     assert_equal "pages/page", attachable.to_trix_content_attachment_partial_path