@Test
    public void testVariableAccess() {
        assertNull(config);
        String configId = "file:" + PATH + "variableaccess.txt";
        ConfigGetter<FunctionTestConfig> getter = new ConfigGetter<>(FunctionTestConfig.class);
        assertVariableAccessValues(getter.getConfig(configId), configId);
    }
Test most data types and features of the config client API,
e.g. parameter access, missing default values, and more.
<p/>
NOTE: this test does NOT test null default values.

@author gjoranv
config/src/test/java/com/yahoo/config/subscription/FunctionTest.java