Add a test to reproduce the bug

Author: li-boxuan

janusgraph-backend-testutils/src/main/java/org/janusgraph/core/AbstractConfiguredGraphFactoryTest.java

@@ -18,6 +18,7 @@
 import org.apache.tinkerpop.gremlin.groovy.engine.GremlinExecutor;
 import org.apache.tinkerpop.gremlin.jsr223.GremlinScriptEngineManager;
 import org.apache.tinkerpop.gremlin.server.Settings;
+import org.apache.tinkerpop.gremlin.structure.T;
 import org.janusgraph.diskstorage.configuration.backend.CommonsConfiguration;
 import org.janusgraph.graphdb.configuration.builder.GraphDatabaseConfigurationBuilder;
 import org.janusgraph.graphdb.database.StandardJanusGraph;

janusgraph-inmemory/src/test/java/org/janusgraph/core/inmemory/InmemoryConfiguredGraphFactoryTest.java

@@ -21,6 +21,8 @@
 import java.util.HashMap;
 import java.util.Map;
 
+import static org.janusgraph.graphdb.configuration.GraphDatabaseConfiguration.ALLOW_CUSTOM_VERTEX_ID_TYPES;
+import static org.janusgraph.graphdb.configuration.GraphDatabaseConfiguration.ALLOW_SETTING_VERTEX_ID;
 import static org.janusgraph.graphdb.configuration.GraphDatabaseConfiguration.GRAPH_NAME;
 import static org.janusgraph.graphdb.configuration.GraphDatabaseConfiguration.STORAGE_BACKEND;
 
@@ -29,6 +31,8 @@ public class InmemoryConfiguredGraphFactoryTest extends AbstractConfiguredGraphF
     protected MapConfiguration getManagementConfig() {
         final Map<String, Object> map = new HashMap<>();
         map.put(STORAGE_BACKEND.toStringWithoutRoot(), "inmemory");
+        map.put(ALLOW_SETTING_VERTEX_ID.toStringWithoutRoot(), "true");
+        map.put(ALLOW_CUSTOM_VERTEX_ID_TYPES.toStringWithoutRoot(), "true");
         return ConfigurationUtil.loadMapConfiguration(map);
     }