### Question:
GraphApi { public Collection<RelationshipType> getAllRelationshipTypes() { Set<RelationshipType> relationships = new HashSet<>(); try (Transaction tx = graphDb.beginTx()) { relationships.addAll(newHashSet(graphDb.getAllRelationshipTypes())); tx.success(); } return relationships; } @Inject  GraphApi(GraphDatabaseService graphDb, CypherUtil cypherUtil, CurieUtil curieUtil); Collection<Node> getEntailment(Node parent, DirectedRelationshipType relationship,
      boolean traverseEquivalentEdges); @AddCuries Graph getNeighbors(Set<Node> nodes, int depth, Set<DirectedRelationshipType> types,
      final Optional<Predicate<Node>> includeNode); Graph getEdges(RelationshipType type, boolean entail, long skip, long limit); Optional<Node> getNode(String id, Optional<String> lblHint); Graph getReachableNodes(Node start, List<String> rels, Set<String> lbls); Collection<RelationshipType> getAllRelationshipTypes(); Collection<String> getAllPropertyKeys();  }### Answer:
@Test public void allRelationshipTypes_areReturned() { assertThat(getFirst(graphApi.getAllRelationshipTypes(), null).name(), is(OwlRelationships.OWL_EQUIVALENT_CLASS.name())); assertThat(getLast(graphApi.getAllRelationshipTypes()).name(), is(OwlRelationships.RDFS_SUBCLASS_OF.name())); }