GroovyClassLoader cl = new GroovyClassLoader();
Class c = cl.parseClass(Thread.currentThread().getContextClassLoader().getResourceAsStream("BookStorage.groovy"));
GroovyObject groovyObject = (GroovyObject)c.newInstance();
groovyObject.invokeMethod("initStorage", new Object[]{});
JsonValue jsonValue = new JsonGeneratorImpl().createJsonObject(groovyObject);
//System.out.println(jsonValue);
assertTrue(jsonValue.isObject());
Iterator<JsonValue> iterator = jsonValue.getElement("books").getElements();
assertEquals("JUnit in Action", iterator.next().getElement("title").getStringValue());
assertEquals("Beginning C# 2008 from novice to professional", iterator.next().getElement("title")