DEV: Rename direct message related models

This is a followup of the previous refactor where we created two new
models to handle all the dedicated logic that was present in the
`ChatChannel` model.

For the sake of consistency, `DMChannel` has been renamed to
`DirectMessageChannel` and the previous `DirectMessageChannel` model is
now named `DirectMessage`. This should help reasoning about direct
messages.

plugins/chat/spec/serializer/chat_message_serializer_spec.rb

@@ -175,7 +175,7 @@ describe ChatMessageSerializer do
 
     context "when flagging DMs" do
       fab!(:dm_channel) do
-        Fabricate(:direct_message_chat_channel, users: [guardian_user, message_poster])
+        Fabricate(:direct_message_channel, users: [guardian_user, message_poster])
       end
       fab!(:dm_message) { Fabricate(:chat_message, user: message_poster, chat_channel: dm_channel) }
 

plugins/chat/spec/serializer/direct_message_channel_serializer_spec.rb

@@ -1,71 +0,0 @@
-# frozen_string_literal: true
-
-require "rails_helper"
-
-describe DirectMessageChannelSerializer do
-  describe "#user" do
-    it "returns you when there are two of us" do
-      me = Fabricate.build(:user)
-      you = Fabricate.build(:user)
-      direct_message_channel = Fabricate.build(:direct_message_channel, users: [me, you])
-
-      serializer =
-        DirectMessageChannelSerializer.new(
-          direct_message_channel,
-          scope: Guardian.new(me),
-          root: false,
-        )
-
-      expect(serializer.users).to eq([you])
-    end
-
-    it "returns you both if there are three of us" do
-      me = Fabricate.build(:user)
-      you = Fabricate.build(:user)
-      other_you = Fabricate.build(:user)
-      direct_message_channel = Fabricate.build(:direct_message_channel, users: [me, you, other_you])
-
-      serializer =
-        DirectMessageChannelSerializer.new(
-          direct_message_channel,
-          scope: Guardian.new(me),
-          root: false,
-        )
-
-      expect(serializer.users).to match_array([you, other_you])
-    end
-
-    it "returns me if there is only me" do
-      me = Fabricate.build(:user)
-      direct_message_channel = Fabricate.build(:direct_message_channel, users: [me])
-
-      serializer =
-        DirectMessageChannelSerializer.new(
-          direct_message_channel,
-          scope: Guardian.new(me),
-          root: false,
-        )
-
-      expect(serializer.users).to eq([me])
-    end
-
-    context "when a user is destroyed" do
-      it "returns a placeholder user" do
-        me = Fabricate(:user)
-        you = Fabricate(:user)
-        direct_message_channel = Fabricate(:direct_message_channel, users: [me, you])
-
-        you.destroy!
-
-        serializer =
-          DirectMessageChannelSerializer.new(
-            direct_message_channel.reload,
-            scope: Guardian.new(me),
-            root: false,
-          ).as_json
-
-        expect(serializer[:users][0][:username]).to eq(I18n.t("chat.deleted_chat_username"))
-      end
-    end
-  end
-end

plugins/chat/spec/serializer/direct_message_serializer_spec.rb

@@ -0,0 +1,52 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+
+describe DirectMessageSerializer do
+  describe "#user" do
+    it "returns you when there are two of us" do
+      me = Fabricate.build(:user)
+      you = Fabricate.build(:user)
+      direct_message = Fabricate.build(:direct_message, users: [me, you])
+
+      serializer = described_class.new(direct_message, scope: Guardian.new(me), root: false)
+
+      expect(serializer.users).to eq([you])
+    end
+
+    it "returns you both if there are three of us" do
+      me = Fabricate.build(:user)
+      you = Fabricate.build(:user)
+      other_you = Fabricate.build(:user)
+      direct_message = Fabricate.build(:direct_message, users: [me, you, other_you])
+
+      serializer = described_class.new(direct_message, scope: Guardian.new(me), root: false)
+
+      expect(serializer.users).to match_array([you, other_you])
+    end
+
+    it "returns me if there is only me" do
+      me = Fabricate.build(:user)
+      direct_message = Fabricate.build(:direct_message, users: [me])
+
+      serializer = described_class.new(direct_message, scope: Guardian.new(me), root: false)
+
+      expect(serializer.users).to eq([me])
+    end
+
+    context "when a user is destroyed" do
+      it "returns a placeholder user" do
+        me = Fabricate(:user)
+        you = Fabricate(:user)
+        direct_message = Fabricate(:direct_message, users: [me, you])
+
+        you.destroy!
+
+        serializer =
+          described_class.new(direct_message.reload, scope: Guardian.new(me), root: false).as_json
+
+        expect(serializer[:users][0][:username]).to eq(I18n.t("chat.deleted_chat_username"))
+      end
+    end
+  end
+end

plugins/chat/spec/serializer/structured_channel_serializer_spec.rb

@@ -5,14 +5,10 @@ RSpec.describe StructuredChannelSerializer do
   fab!(:guardian) { Guardian.new(user1) }
   fab!(:user2) { Fabricate(:user) }
   fab!(:user3) { Fabricate(:user) }
-  fab!(:channel1) { Fabricate(:chat_channel) }
-  fab!(:channel2) { Fabricate(:chat_channel) }
-  fab!(:channel3) do
-    Fabricate(:chat_channel, chatable: Fabricate(:direct_message_channel, users: [user1, user2]))
-  end
-  fab!(:channel4) do
-    Fabricate(:chat_channel, chatable: Fabricate(:direct_message_channel, users: [user1, user3]))
-  end
+  fab!(:channel1) { Fabricate(:category_channel) }
+  fab!(:channel2) { Fabricate(:category_channel) }
+  fab!(:channel3) { Fabricate(:direct_message_channel, users: [user1, user2]) }
+  fab!(:channel4) { Fabricate(:direct_message_channel, users: [user1, user3]) }
   fab!(:membership1) do
     Fabricate(:user_chat_channel_membership, user: user1, chat_channel: channel1)
   end