private String getCacheKey(Object bean, String beanName) {
      return StringUtils.hasLength(beanName) ? beanName : bean.getClass().getName();
    }
{@link BeanPostProcessor} to handle {@link SpringSpy} definitions. Registered as a
separate processor so that it can be ordered above AOP post processors.
spock-spring/src/main/java/org/spockframework/spring/mock/SpockMockPostprocessor.java