FIX: Ensure that post action moderation post uses the site's default locale.

https://meta.discourse.org/t/a-post-in-looking-for-someone-to-customize-discourse-to-create-a-forum-site-requires-staff-attention/67468/5?u=tgxworld

spec/integration/admin/flags_spec.rb

@@ -0,0 +1,55 @@
+require 'rails_helper'
+
+RSpec.describe "Managing flags as an admin" do
+  let(:admin) { Fabricate(:admin) }
+  let(:post) { Fabricate(:post) }
+  let(:user) { Fabricate(:user) }
+
+  before do
+    sign_in(admin)
+  end
+
+  context 'viewing flags' do
+    it 'should return the right response when nothing is flagged' do
+      get '/admin/flags.json'
+
+      expect(response).to be_success
+
+      data = ::JSON.parse(response.body)
+      expect(data["users"]).to eq([])
+      expect(data["posts"]).to eq([])
+    end
+
+    it 'should return the right response' do
+      PostAction.act(user, post, PostActionType.types[:spam])
+
+      get '/admin/flags.json'
+
+      expect(response).to be_success
+
+      data = ::JSON.parse(response.body)
+      data["users"].length == 2
+      data["posts"].length == 1
+    end
+  end
+
+  context 'agreeing with a flag' do
+    it 'should work' do
+      SiteSetting.allow_user_locale = true
+      post_action = PostAction.act(user, post, PostActionType.types[:spam], message: 'bad')
+      admin.update!(locale: 'ja')
+
+      xhr :post, "/admin/flags/agree/#{post.id}"
+
+      expect(response).to be_success
+
+      post_action.reload
+
+      expect(post_action.agreed_by_id).to eq(admin.id)
+
+      post = Post.offset(1).last
+
+      expect(post.raw).to eq(I18n.with_locale(:en) { I18n.t('flags_dispositions.agreed') })
+    end
+  end
+end