protected static String getConfigStr(String name) {
        if (cacheMap.containsKey(name)) {
            return (String) cacheMap.get(name);
        }

        String val = getConfig(name);

        if (StringUtils.isBlank(val)) {
            return null;
        }

        cacheMap.put(name, val);
        return val;
    }
@Test
    public void testGetConfigStr() {
        // clear cache
        DashboardConfig.clearCache();

        // if not set, return null
        assertEquals(null, DashboardConfig.getConfigStr("a"));

        // test property
        System.setProperty("a", "111");
        assertEquals("111", DashboardConfig.getConfigStr("a"));

        // test env
        environmentVariables.set("a", "222");
        // return value in cache
        assertEquals("111", DashboardConfig.getConfigStr("a"));

        // clear cache and then test
        DashboardConfig.clearCache();
        assertEquals("222", DashboardConfig.getConfigStr("a"));
    }