DEV: implements initial messages component (#21727)

This should also make `message_notifications_with_sidebar_spec.rb` more resilient as we are now checking for `is-persisted` class instead of checking for the absence of `is-staged`.

plugins/chat/spec/system/page_objects/chat/chat.rb

@@ -17,8 +17,8 @@ module PageObjects
         visit("/chat")
       end
 
-      def visit_channel(channel)
-        visit(channel.url)
+      def visit_channel(channel, message_id: nil)
+        visit(channel.url + (message_id ? "/#{message_id}" : ""))
         has_no_css?(".chat-channel--not-loaded-once")
         has_no_css?(".chat-skeleton")
       end

plugins/chat/spec/system/page_objects/chat/chat_channel.rb

@@ -7,6 +7,10 @@ module PageObjects
         @composer ||= PageObjects::Components::Chat::Composer.new(".chat-channel")
       end
 
+      def messages
+        @messages ||= PageObjects::Components::Chat::Messages.new(".chat-channel")
+      end
+
       def replying_to?(message)
         find(".chat-channel .chat-reply", text: message.message)
       end
@@ -115,10 +119,12 @@ module PageObjects
       end
 
       def send_message(text = nil)
+        text ||= Faker::Lorem.characters(number: SiteSetting.chat_minimum_message_length)
         text = text.chomp if text.present? # having \n on the end of the string counts as an Enter keypress
         fill_composer(text)
         click_send_message
         click_composer
+        has_no_loading_skeleton?
       end
 
       def reply_to(message)

plugins/chat/spec/system/page_objects/chat/chat_thread.rb

@@ -12,6 +12,10 @@ module PageObjects
           PageObjects::Components::Chat::ComposerMessageDetails.new(".chat-thread")
       end
 
+      def messages
+        @messages ||= PageObjects::Components::Chat::Messages.new(".chat-thread")
+      end
+
       def header
         find(".chat-thread__header")
       end
@@ -47,6 +51,7 @@ module PageObjects
       end
 
       def send_message(text = nil)
+        text ||= Faker::Lorem.characters(number: SiteSetting.chat_minimum_message_length)
         text = text.chomp if text.present? # having \n on the end of the string counts as an Enter keypress
         fill_composer(text)
         click_send_message

plugins/chat/spec/system/page_objects/chat/components/message.rb

@@ -0,0 +1,30 @@
+# frozen_string_literal: true
+
+module PageObjects
+  module Components
+    module Chat
+      class Message < PageObjects::Components::Base
+        attr_reader :context
+
+        SELECTOR = ".chat-message-container"
+
+        def initialize(context)
+          @context = context
+        end
+
+        def exists?(**args)
+          selectors = SELECTOR
+          selectors += "[data-id=\"#{args[:id]}\"]" if args[:id]
+          selectors += ".is-persisted" if args[:persisted]
+          selectors += ".is-staged" if args[:staged]
+
+          if args[:text]
+            find(context).has_selector?(selectors + " " + ".chat-message-text", text: args[:text])
+          else
+            find(context).has_selector?(selectors)
+          end
+        end
+      end
+    end
+  end
+end

plugins/chat/spec/system/page_objects/chat/components/messages.rb

@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+module PageObjects
+  module Components
+    module Chat
+      class Messages < PageObjects::Components::Base
+        attr_reader :context
+
+        SELECTOR = ".chat-message-container"
+
+        def initialize(context)
+          @context = context
+        end
+
+        def has_message?(**args)
+          PageObjects::Components::Chat::Message.new(".chat-channel").exists?(**args)
+        end
+
+        def has_no_message?(**args)
+          !has_message?(**args)
+        end
+      end
+    end
+  end
+end