test fails when asciidoc-bootstrap-backend is set.

AsciidocBackendTest

import static org.asciidoctor.OptionsBuilder.options;
import static org.junit.Assert.*;

import org.asciidoctor.Asciidoctor;
import org.asciidoctor.Options;
import org.asciidoctor.Asciidoctor.Factory;
import org.asciidoctor.OptionsBuilder;
import org.jruby.exceptions.RaiseException;
import org.junit.Test;


public class AsciidocBackendTest {

   private String contents = "= AsciiDoc Writer's Guide\n" +
   		"Doc Writer <doc.writer@asciidoc.org>\n" +
   		"v1.0, 2013-01-01\n" +
   		":toc:\n\n" +
   		"== A\n" +
   		"toc::[]\n";

   @Test //(expected=RaiseException.class)
   public void fialOnBackend() {
      Asciidoctor asciidoctor = Factory.create();
      OptionsBuilder options = options().backend("/Users/v/Downloads/bootstrap-3.0.1");
      String out = asciidoctor.render(contents , options);
      assertNotNull(out);
      assertFalse(out.isEmpty());
   }

}