### Question:
InstanceConfig extends HelixProperty { public Map<String, String> getDomainAsMap() { String domain = getDomainAsString(); Map<String, String> domainAsMap = new HashMap<>(); if (domain == null || domain.isEmpty()) { return domainAsMap; } String[] pathPairs = domain.trim().split(","); for (String pair : pathPairs) { String[] values = pair.split("="); if (values.length != 2 || values[0].isEmpty() || values[1].isEmpty()) { throw new IllegalArgumentException( String.format("Domain-Value pair %s is not valid.", pair)); } domainAsMap.put(values[0].trim(), values[1].trim()); } return domainAsMap; } InstanceConfig(String instanceId);  InstanceConfig(ZNRecord record); String getHostName(); void setHostName(String hostName); String getPort(); void setPort(String port); @Deprecated String getZoneId(); void setZoneId(String zoneId); @Deprecated String getDomain(); String getDomainAsString(); Map<String, String> getDomainAsMap(); void setDomain(String domain); int getWeight(); void setWeight(int weight); List<String> getTags(); void addTag(String tag); void removeTag(String tag); boolean containsTag(String tag); boolean getInstanceEnabled(); void setInstanceEnabled(boolean enabled); long getInstanceEnabledTime(); @Deprecated boolean getInstanceEnabledForPartition(String partition); boolean getInstanceEnabledForPartition(String resource, String partition); @Deprecated List<String> getDisabledPartitions(); List<String> getDisabledPartitions(String resourceName); Map<String, List<String>> getDisabledPartitionsMap(); @Deprecated void setInstanceEnabledForPartition(String partitionName, boolean enabled); void setInstanceEnabledForPartition(String resourceName, String partitionName,
      boolean enabled); boolean isInstanceInDomain(String domain); boolean isDelayRebalanceEnabled(); void setDelayRebalanceEnabled(boolean enabled); int getMaxConcurrentTask(); void setMaxConcurrentTask(int maxConcurrentTask); int getTargetTaskThreadPoolSize(); void setTargetTaskThreadPoolSize(int targetTaskThreadPoolSize); Map<String, Integer> getInstanceCapacityMap(); void setInstanceCapacityMap(Map<String, Integer> capacityDataMap); @Override boolean equals(Object obj); @Override int hashCode(); String getInstanceName(); @Override boolean isValid(); static InstanceConfig toInstanceConfig(String instanceId); boolean validateTopologySettingInInstanceConfig(ClusterConfig clusterConfig,
      String instanceName); static final int WEIGHT_NOT_SET; static final int MAX_CONCURRENT_TASK_NOT_SET; }### Answer:
@Test public void testGetParsedDomainEmptyDomain() { InstanceConfig instanceConfig = new InstanceConfig(new ZNRecord("id")); Map<String, String> parsedDomain = instanceConfig.getDomainAsMap(); Assert.assertTrue(parsedDomain.isEmpty()); }