FEATURE: Report edit conflicts when saving draft. (#6585)

spec/requests/draft_controller_spec.rb

@@ -13,6 +13,34 @@ describe DraftController do
     expect(Draft.get(user, 'xyz', 0)).to eq('my data')
   end
 
+  it 'checks for an conflict on update' do
+    user = sign_in(Fabricate(:user))
+    post = Fabricate(:post, user: user)
+
+    post "/draft.json", params: {
+      username: user.username,
+      draft_key: "topic",
+      sequence: 0,
+      data: "{}",
+      post_id: post.id,
+      original_text: post.raw
+    }
+
+    expect(JSON.parse(response.body)['conflict_user']).to eq(nil)
+
+    post "/draft.json", params: {
+      username: user.username,
+      draft_key: "topic",
+      sequence: 0,
+      data: "{}",
+      post_id: post.id,
+      original_text: "something else"
+    }
+
+    expect(JSON.parse(response.body)['conflict_user']['id']).to eq(post.last_editor.id)
+    expect(JSON.parse(response.body)['conflict_user']).to include('avatar_template')
+  end
+
   it 'destroys drafts when required' do
     user = sign_in(Fabricate(:user))
     Draft.set(user, 'xxx', 0, 'hi')