Add unit test for parsing ja strings

.gitignore

@@ -1,4 +1,5 @@
 .DS_Store
+coverage/
 .buildpath
 .project
 .settings/

db/migrate/001_create_messenger_settings.rb

@@ -3,7 +3,7 @@
 class CreateMessengerSettings < ActiveRecord::Migration
   def change
     create_table :messenger_settings do |t|
-      t.belongs_to :project, null: false
+      t.belongs_to :project, null: false, index: true
       t.string :messenger_url
       t.string :messenger_icon
       t.string :messenger_channel

test/unit/i18n_test.rb

@@ -25,7 +25,7 @@ module Redmine
                                              'config',
                                              'locales',
                                              '*.yml')].size
-      assert_equal lang_files_count, 2
+      assert_equal lang_files_count, 3
       valid_languages.each do |lang|
         assert set_language_if_valid(lang)
       end
@@ -34,7 +34,8 @@ module Redmine
       assert_equal 'Messenger Benutzer', l(:label_settings_messenger_username)
       ::I18n.locale = 'en'
       assert_equal 'Messenger username', l(:label_settings_messenger_username)
-
+      ::I18n.locale = 'ja'
+      assert_equal 'メッセンジャーのユーザー名', l(:label_settings_messenger_username)
       set_language_if_valid('en')
     end
   end