How to test subscription with DgsReactiveQueryExecutor

[hantsy]

In a webflux application, I tried to create a simple test to verify if the subscription works.

@SpringBootTest()
@Slf4j
class SubscriptionTests {

    @Autowired
    DgsReactiveQueryExecutor dgsQueryExecutor;

    @MockBean
    PostService postService;

    @MockBean
    AuthorService authorService;

    @Autowired
    PostsDataFetcher dataFetcher;

    @Test
    void createCommentAndSubscription() {
        when(postService.addComment(any(CommentInput.class))).thenReturn(Mono.just(UUID.randomUUID()));
        when(postService.getCommentById(anyString())).thenReturn(Mono.just(
                Comment.builder().id(UUID.randomUUID().toString())
                        .content("test comment")
                        .postId(UUID.randomUUID().toString())
                        .build()
        ));

        String query = "subscription onCommentAdded { commentAdded { id postId content } }";
        Mono<ExecutionResult> executionResult = dgsQueryExecutor.execute(query, Collections.EMPTY_MAP);

        //var publisher = executionResult.flatMapMany(result -> Flux.from((Publisher<ExecutionResult>) result.getData()));

        var verifier = StepVerifier.create(executionResult)
                .consumeNextWith(it -> {
                    log.debug("publisher: {}", it);
                    var data = (Map<String, Map<String, Object>>) it.getData();
                    log.debug("data: {}", data);
                    assertThat(data.get("commentAdded").get("content")).isEqualTo("test comment");
                })
                .thenCancel()
                .verifyLater();

        // add comment
        dataFetcher.addComment(
                        CommentInput.builder()
                                .postId(UUID.randomUUID().toString())
                                .content("test content")
                                .build()
                )
                .as(StepVerifier::create)
                .consumeNextWith(comment -> assertThat(comment.getContent()).isEqualTo("test comment"))
                .verifyComplete();

        verifier.verify();
        verify(postService, times(1)).addComment(any(CommentInput.class));
        verify(postService, times(1)).getCommentById(anyString());
        verifyNoMoreInteractions(postService);
    }
}

The data from subscription always return a null object.

But in other tests which used DgsQueryExecutor, manually cast the getData to a Publisher<ExecutionResult>., it works.

[hantsy]

Any suggestions?