### Question:
VnfAdapterVfModuleObjectMapper { protected void addPairToMap(Map<String, Object> paramsMap, String keyPrefix, String key, String value) { addPairToMap(paramsMap, keyPrefix, key, Collections.singletonList(value)); }  @PostConstruct void init(); CreateVfModuleRequest createVfModuleRequestMapper(RequestContext requestContext, CloudRegion cloudRegion,
            OrchestrationContext orchestrationContext, ServiceInstance serviceInstance, GenericVnf genericVnf,
            VfModule vfModule, VolumeGroup volumeGroup, String sdncVnfQueryResponse, String sdncVfModuleQueryResponse); Map<String, Object> buildVfModuleParamsMap(RequestContext requestContext, ServiceInstance serviceInstance,
            GenericVnf genericVnf, VfModule vfModule, String sdncVnfQueryResponse, String sdncVfModuleQueryResponse); DeleteVfModuleRequest deleteVfModuleRequestMapper(RequestContext requestContext, CloudRegion cloudRegion,
            ServiceInstance serviceInstance, GenericVnf genericVnf, VfModule vfModule);  }### Answer:
@Test public void addPairToMapTest() { Map<String, Object> map = new HashMap<>(); mapper.addPairToMap(map, "test", "_key", Arrays.asList("a", "b")); assertEquals("a,b", map.get("test_key")); mapper.addPairToMap(map, "test", "_key2", Arrays.asList()); assertThat(map.containsKey("test_key2"), equalTo(false)); mapper.addPairToMap(map, "test", "_key3", "myVal"); assertEquals("myVal", map.get("test_key3")); }