diff --git a/.github/workflows/rubyonrails.yml b/.github/workflows/rubyonrails.yml
index 80dddcf3..77a50cff 100644
--- a/.github/workflows/rubyonrails.yml
+++ b/.github/workflows/rubyonrails.yml
@@ -156,7 +156,7 @@ jobs:
           cd /opt/redmine
           bundle exec rake redmine:dmsf_webdav_test_on
           bundle exec rails server -u webrick -e test -d
-          sleep(5)
+          sleep 5
           litmus http://localhost:3000/dmsf/webdav/dmsf_test_project admin admin
           kill `cat tmp/pids/server.pid`
           bundle exec rake redmine:dmsf_webdav_test_off
diff --git a/lib/redmine_dmsf/webdav/base_resource.rb b/lib/redmine_dmsf/webdav/base_resource.rb
index 63ab20da..4ec91cfb 100644
--- a/lib/redmine_dmsf/webdav/base_resource.rb
+++ b/lib/redmine_dmsf/webdav/base_resource.rb
@@ -30,14 +30,16 @@ module RedmineDmsf
 
       attr_reader :public_path
 
-      DIR_FILE = %(
-                    <tr>
-                      <td class=\"name\"><a href=\"%s\">%s</a></td>
-                      <td class=\"size\">%s</td>
-                      <td class=\"type\">%s</td>
-                      <td class=\"mtime\">%s</td>
-                    </tr>
-                   )
+      unless const_defined?(DIR_FILE)
+        DIR_FILE = %(
+                      <tr>
+                        <td class=\"name\"><a href=\"%s\">%s</a></td>
+                        <td class=\"size\">%s</td>
+                        <td class=\"type\">%s</td>
+                        <td class=\"mtime\">%s</td>
+                      </tr>
+                     )
+      end
 
       def initialize(path, request, response, options)
         raise NotFound if Setting.plugin_redmine_dmsf['dmsf_webdav'].blank?