I have a problem my code using your Great module ElasticSearch. but a test w/ Devel::Cover occurs error like below. but, wo/ Devel::Cover was fine. How can I solve this problem?

ElasticSearch-rocks

$ HARNESS_PERL_SWITCHES=-MDevel::Cover=+ignore,local,+ignore,root \
carton exec -Ilib -- prove -lv --timer --formatter TAP::Formatter::JUnit t/*
.....

[Tue Jun 25 14:26:33 2013] [error] [ERROR] ** ElasticSearch::Error::Request at local/lib/perl5/ElasticSearch/Transport/HTTP.pm line 67 :
SearchPhaseExecutionException[Failed to execute phase [query], total failure; shardFailures {[X2QKjOXGSHykChFtJCtGPA][2013-06-10][3]: SearchParseException[[2013-06-10][3]: query[sort:[*],from[-1],size[-1]: Parse Failure [Failed to parse source [{"query":{"prefix":{"sort":["publish_date:desc"],"title":"오리"}}}]]]; nested: SearchParseException[[2013-06-10][3]: query[sort:[*],from[-1],size[-1]: Parse Failure [No parser for element [title]]]; }{[X2QKjOXGSHykChFtJCtGPA][2013-06-10][2]: SearchParseException[[2013-06-10][2]: query[sort:[*],from[-1],size[-1]: Parse Failure [Failed to parse source [{"query":{"prefix":{"sort":["publish_date:desc"],"title":"오리"}}}]]]; nested: SearchParseException[[2013-06-10][2]: query[sort:[*],from[-1],size[-1]: Parse Failure [No parser for element [title]]]; }{[X2QKjOXGSHykChFtJCtGPA][2013-06-10][1]: SearchParseException[[2013-06-10][1]: query[sort:[*],from[-1],size[-1]: Parse Failure [Failed to parse source [{"query":{"prefix":{"sort":["publish_date:desc"],"title":"오리"}}}]]]; nested: SearchParseException[[2013-06-10][1]: query[sort:[*],from[-1],size[-1]: Parse Failure [No parser for element [title]]]; }{[X2QKjOXGSHykChFtJCtGPA][2013-06-10][4]: SearchParseException[[2013-06-10][4]: query[sort:[*],from[-1],size[-1]: Parse Failure [Failed to parse source [{"query":{"prefix":{"sort":["publish_date:desc"],"title":"오리"}}}]]]; nested: SearchParseException[[2013-06-10][4]: query[sort:[*],from[-1],size[-1]: Parse Failure [No parser for element [title]]]; }{[X2QKjOXGSHykChFtJCtGPA][2013-06-10][0]: SearchParseException[[2013-06-10][0]: query[sort:[*],from[-1],size[-1]: Parse Failure [Failed to parse source [{"query":{"prefix":{"sort":["publish_date:desc"],"title":"오리"}}}]]]; nested: SearchParseException[[2013-06-10][0]: query[sort:[*],from[-1],size[-1]: Parse Failure [No parser for element [title]]]; }]

With vars:{
  'server' => '222.122.224.44:9200',
  'status_code' => 500,
  'request' => {
    'data' => {
      'query' => {
        'prefix' => {
          'sort' => [
            'publish_date:desc'
          ],
          'title' => "\x{ec}\x{98}\x{a4}\x{eb}\x{a6}\x{ac}"
        }
      }
    },
    'qs' => {},
    'post_process' => undef,
    'as_json' => undef,
    'method' => 'GET',
    'cmd' => '/_all/_search'
  },
  'status_msg' => 'Internal Server Error'
}

My code using elasticsearch is below...

$self->ES->search(
        index => undef,
        query => {
            prefix => { 
                title => $keyword ,
            },
            sort  => ['publish_date:desc']
        },
    );