The code of Method publishConfig of Class ConsulDynamicConfiguration:
```java
    @Override
    public boolean publishConfig(String key, String group, String content) throws UnsupportedOperationException {
        String normalizedKey = convertKey(group, key);
        return kvClient.putValue(normalizedKey + PATH_SEPARATOR + content);
    }
```
We want put a config with value with the "content", but the method just add the "content" to the key and put a null value.
private static ConsulProcess consul;
    private static URL configCenterUrl;
    private static ConsulDynamicConfiguration configuration;
    private static Consul client;
    private static KeyValueClient kvClient;
    @BeforeAll
    public static void setUp() throws Exception {
        consul = ConsulStarterBuilder.consulStarter()
                .build()
                .start();
        configCenterUrl = URL.valueOf("consul://localhost:" + consul.getHttpPort());
        configuration = new ConsulDynamicConfiguration(configCenterUrl);
        client = Consul.builder().withHostAndPort(HostAndPort.fromParts("localhost", consul.getHttpPort())).build();
        kvClient = client.keyValueClient();
    }
    @AfterAll
    public static void tearDown() throws Exception {
        consul.close();
        configuration.close();
    }
    @Test
    public void testGetConfig() {
        kvClient.putValue("/dubbo/config/dubbo/foo", "bar");
        
        assertEquals("bar", configuration.getConfig("foo", "dubbo"));
        
        assertEquals("bar", configuration.getConfig("foo", "dubbo"));
        Assertions.assertNull(configuration.getConfig("not-exist", "dubbo"));