diff --git a/lib/redmine_messenger.rb b/lib/redmine_messenger.rb
index 8de5dc5..ffad348 100644
--- a/lib/redmine_messenger.rb
+++ b/lib/redmine_messenger.rb
@@ -22,7 +22,7 @@ module RedmineMessenger
     end
 
     def settings
-      if Setting[:plugin_redmine_messenger].class == Hash
+      if Setting[:plugin_redmine_messenger].instance_of? Hash
         new_settings = ActiveSupport::HashWithIndifferentAccess.new(Setting[:plugin_redmine_messenger])
         Setting.plugin_redmine_messenger = new_settings
         new_settings
diff --git a/test/unit/issue_test.rb b/test/unit/issue_test.rb
index 87d29fe..39b6504 100644
--- a/test/unit/issue_test.rb
+++ b/test/unit/issue_test.rb
@@ -22,7 +22,7 @@ class IssueTest < ActiveSupport::TestCase
 
   def test_create
     issue = Issue.new(project_id: 1, tracker_id: 1, author_id: 3, subject: 'test_create')
-    assert issue.save
+    assert_save issue
     assert_equal issue.tracker.default_status, issue.status
     assert issue.description.nil?
   end