Symfony\Component\VarDumper\Dumper\HtmlDumper::setDumpBoundaries PHP Method

    public function setDumpBoundaries($prefix, $suffix)
    {
        $this->dumpPrefix = $prefix;
        $this->dumpSuffix = $suffix;
    }

 public function testCustomDumper()
 {
     $output = '';
     $lineDumper = function ($line) use(&$output) {
         $output .= $line;
     };
     $dumper = new HtmlDumper($lineDumper);
     $dumper->setDumpHeader('');
     $dumper->setDumpBoundaries('<pre class=sf-dump-test id=%s data-indent-pad="%s">', '</pre><script>Sfdump("%s")</script>');
     $extension = new DumpExtension(new VarCloner(), $dumper);
     $twig = new \Twig_Environment($this->getMockBuilder('Twig_LoaderInterface')->getMock(), array('debug' => true, 'cache' => false, 'optimizations' => 0));
     $dump = $extension->dump($twig, array(), 'foo');
     $dump = preg_replace('/sf-dump-\\d+/', 'sf-dump', $dump);
     $this->assertEquals('<pre class=sf-dump-test id=sf-dump data-indent-pad="  ">"' . "<span class=sf-dump-str title=\"3 characters\">foo</span>\"\n" . "</pre><script>Sfdump(\"sf-dump\")</script>\n", $dump, 'Custom dumper should be used to dump data.');
     $this->assertEmpty($output, 'Dumper output should be ignored.');
 }