4 files changed, 61 insertions, 2 deletions
diff --git a/actiontext/lib/action_text/attachables/remote_image.rb b/actiontext/lib/action_text/attachables/remote_image.rb
index 650b11862b..c5819ef1f5 100644
--- a/actiontext/lib/action_text/attachables/remote_image.rb
+++ b/actiontext/lib/action_text/attachables/remote_image.rb
@@ -14,7 +14,7 @@ module ActionText
 
         private
           def content_type_is_image?(content_type)
-            content_type.to_s =~ /^image(\/.+|$)/
+            content_type.to_s.match?(/^image(\/.+|$)/)
           end
 
           def attributes_from_node(node)
diff --git a/actiontext/lib/action_text/attachment_gallery.rb b/actiontext/lib/action_text/attachment_gallery.rb
index 45afbff058..48ba9f830c 100644
--- a/actiontext/lib/action_text/attachment_gallery.rb
+++ b/actiontext/lib/action_text/attachment_gallery.rb
@@ -23,7 +23,7 @@ module ActionText
         Fragment.wrap(content).find_all(SELECTOR).select do |node|
           node.children.all? do |child|
             if child.text?
-              child.text =~ /\A(\n|\ )*\z/
+              /\A(\n|\ )*\z/.match?(child.text)
             else
               child.matches? ATTACHMENT_SELECTOR
             end
diff --git a/actiontext/lib/action_text/engine.rb b/actiontext/lib/action_text/engine.rb
index 51ff5b575b..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
 
@@ -46,5 +50,12 @@ module ActionText
         before_action { ActionText::Content.renderer = ApplicationController.renderer.new(request.env) }
       end
     end
+
+    initializer "action_text.system_test_helper" do
+      ActiveSupport.on_load(:action_dispatch_system_test_case) do
+        require "action_text/system_test_helper"
+        include ActionText::SystemTestHelper
+      end
+    end
   end
 end
diff --git a/actiontext/lib/action_text/system_test_helper.rb b/actiontext/lib/action_text/system_test_helper.rb
new file mode 100644
index 0000000000..77fc9eb50b
--- /dev/null
+++ b/actiontext/lib/action_text/system_test_helper.rb
@@ -0,0 +1,48 @@
+# frozen_string_literal: true
+
+module ActionText
+  module SystemTestHelper
+    # Locates a Trix editor and fills it in with the given HTML.
+    #
+    # The editor can be found by:
+    # * its +id+
+    # * its +placeholder+
+    # * its +aria-label+
+    # * the +name+ of its input
+    #
+    # Examples:
+    #
+    #   # <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 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>"
+    def fill_in_rich_text_area(locator = nil, with:)
+      find(:rich_text_area, locator).execute_script("this.editor.loadHTML(arguments[0])", with.to_s)
+    end
+  end
+end
+
+Capybara.add_selector :rich_text_area do
+  label "rich-text area"
+  xpath do |locator|
+    if locator.nil?
+      XPath.descendant(:"trix-editor")
+    else
+      input_located_by_name = XPath.anywhere(:input).where(XPath.attr(:name) == locator).attr(:id)
+
+      XPath.descendant(:"trix-editor").where \
+        XPath.attr(:id).equals(locator) |
+        XPath.attr(:placeholder).equals(locator) |
+        XPath.attr(:"aria-label").equals(locator) |
+        XPath.attr(:input).equals(input_located_by_name)
+    end
+  end
+end