public void loadInstanceMetadataSnapshot(ConcurrentMap<Service, ConcurrentMap<String, InstanceMetadata>> snapshot) {
        ConcurrentMap<Service, ConcurrentMap<String, InstanceMetadata>> oldSnapshot = instanceMetadataMap;
        instanceMetadataMap = snapshot;
        oldSnapshot.clear();
    }
@Test
    void testLoadInstanceMetadataSnapshot() {
        namingMetadataManager.loadInstanceMetadataSnapshot(new ConcurrentHashMap<>());
        Map<Service, ConcurrentMap<String, InstanceMetadata>> instanceMetadataSnapshot = namingMetadataManager.getInstanceMetadataSnapshot();
        
        assertEquals(0, instanceMetadataSnapshot.size());
    }