Implement `yaml_write' action

features/steps/remote_steps.rb

@@ -22,6 +22,10 @@ Then /^the remote file "([^"]+)" must contain exactly "([^"]+)"$/ do |path, cont
   check_exact_file_content path, content
 end
 
+Then /^the remote file "([^"]+)" must match \/([^\/]+)\/$/ do |path, pattern|
+  check_file_content path, /#{pattern}/, true
+end
+
 def stat_mode(path)
   in_current_dir do
     ('%o' % [File::Stat.new(path).mode])[-4, 4]