use strict;
use Mail::IMAPClient;
use Data::Dumper;

sub test_quote {
    print "Parameters: " . Dumper \@_;
    my @quoted=  Mail::IMAPClient->_quote_search(@_);
    print "Result    : " . Dumper \@quoted;
};

test_quote( q(SUBJECT "SUBJECT \"test email \"abc123\" approved\"));
test_quote( SUBJECT => q(test email "abc123" approved) );
__END__

Parameters: $VAR1 = [
          'SUBJECT "SUBJECT \\"test email \\"abc123\\" approved\\"'
        ];
Result    : $VAR1 = [
          'SUBJECT "SUBJECT \\"test email \\"abc123\\" approved\\"'
        ];
Parameters: $VAR1 = [
          'SUBJECT',
          'test email "abc123" approved'
        ];
Result    : $VAR1 = [
          'SUBJECT',
          '{28}
test email "abc123" approved'
        ];