void add(String name, String value) {
        filters.put("Filter." + index + ".Name", name);
        filters.put("Filter." + index + ".Value.1", value);
        ++index;
    }
@Test
    public void add() {
        // given
        Filter filter = new Filter();

        // when
        filter.add("key", "value");
        filter.add("second-key", "second-value");
        Map<String, String> result = filter.getFilterAttributes();

        // then
        assertEquals(4, result.size());
        assertEquals("key", result.get("Filter.1.Name"));
        assertEquals("value", result.get("Filter.1.Value.1"));
        assertEquals("second-key", result.get("Filter.2.Name"));
        assertEquals("second-value", result.get("Filter.2.Value.1"));
    }