paramMap = filter.parseQueryString("=", "UTF-8");
        assertEquals(1, paramMap.size());
        assertEquals("", paramMap.get("")[0]);

    }

    public void test_decode() throws IOException {
        final EncodingFilter filter = new EncodingFilter();
        Map<String, String[]> paramMap;

        paramMap = filter.parseQueryString("a=%E3%83%86%E3%82%B9%E3%83%88", "UTF-8");

        });
        final PermissionHelper permissionHelper = ComponentUtil.getPermissionHelper();
        body.permissions = stream(entity.getPermissions()).get(stream -> stream.map(s -> permissionHelper.decode(s))
                .filter(StringUtil::isNotBlank).distinct().collect(Collectors.joining("\n")));
        body.virtualHosts = stream(entity.getVirtualHosts())

        });
        final PermissionHelper permissionHelper = ComponentUtil.getPermissionHelper();
        body.permissions = stream(entity.getPermissions()).get(stream -> stream.map(s -> permissionHelper.decode(s))
                .filter(StringUtil::isNotBlank).distinct().collect(Collectors.joining("\n")));
        body.virtualHosts = stream(entity.getVirtualHosts())

        } catch (final UnsupportedEncodingException e) {
            throw new FessSystemException("Unsupported encoding.", e);
        }
    }

    public void test_decodeUrl_ok() throws Exception {
        String url, exp;
        final FessFileTransformer transformer = createInstance();

        url = "";
        exp = "";
        assertEquals(exp, transformer.decodeUrlAsName(url, true));

               ...