code: function only( testName, expected, callback, async ) {
  	var newTest;
  
  	if ( focused )  { return; }
  
  	QUnit.config.queue.length = 0;
  	focused = true;
  
  	if ( arguments.length === 2 ) {
  		callback = expected;
  		expected = null;
  	}
  
  	newTest = new Test({
  		testName: testName,
  		expected: expected,
  		async: async,
  		callback: callback
  	});
  
  	newTest.queue();
  }
docs: Will be exposed as QUnit.only