assertEquals("yyy", systemHelper.getHostname());
        } finally {
            envMap.remove("HOSTNAME");
        }
    }

    @Test
    public void test_getInstanceId_withoutTargetName() {
        // When scheduler.target.name is blank, instanceId is hostname:pid
        ComponentUtil.setFessConfig(new FessConfig.SimpleImpl() {
            private static final long serialVersionUID = 1L;