GrailsWebRequest webRequest = bindMockHttpRequest();
// Initialize out and codecOut as it is done in GroovyPage.initRun
OutputEncodingStack outputStack = OutputEncodingStack.currentStack(true, target, false, true);
GrailsPrintWriter out = outputStack.getOutWriter();
webRequest.setOut(out);
GrailsPrintWriter codecOut = new CodecPrintWriter(out, getEncoder(new MockGrailsApplication(), CodecWithClosureProperties.class), registry);
// print some output
codecOut.print("hola");
codecOut.flush();
out.print("1");
out.print("2");
out.print("3");
// similar as taglib call
FastStringWriter bufferWriter=new FastStringWriter();
GrailsPrintWriter out2=new GrailsPrintWriter(bufferWriter);
outputStack.push(out2);
out.print("4");
codecOut.print("A");
codecOut.flush();
outputStack.pop();