Unit Testing Data Fetcher with DGS WebFlux

[miles-po]

Is there anyone out there using DGS WebFlux and writing unit tests for the data fetcher? How did you do it?

Using Java 17, Spring Boot 2.7.3, DGS 5.2.2.

Tried the following after reading the docs (and Google searches for the WebFlux differences) and ended up with this.

@ExtendWith(MockitoExtension.class)
@SpringBootTest(classes = { DgsAutoConfiguration.class, DgsWebFluxAutoConfiguration.class, WebFluxConfigurationSupport.class,
        SessionDataFetcher.class, ImportedScalars.class, IpAddressScalar.class, Iso8601DateTimeScalar.class })
@ActiveProfiles("dev")
class SessionDataFetcherTest {
    private static final UUID SESSION_UUID = UUID.randomUUID();
    private static final Session VALID_SESSION = Session.builder()
            .uuid(SESSION_UUID)
            .validUntil(Instant.now().plus(1, ChronoUnit.HOURS)).build();
    private static final String SESSION_QUERY = """
                    {
                      session(uuid: "%s") {
                        uuid
                      }
                    }
                    """.formatted(SESSION_UUID);

    @Autowired
    DgsQueryExecutor dgsQueryExecutor;

    @MockBean
    private SessionService sessionService; // Internal service, not Spring or DGS-related

    @MockBean
    private ObjectMapper objectMapper;

    @Test
    public void session_withUuid() {
        when(sessionService.getSession(SESSION_UUID))
                .thenReturn(Mono.just(VALID_SESSION));

        val session = dgsQueryExecutor.executeAndExtractJsonPathAsObject(
                SESSION_QUERY, "data.session", Session.class);

        assertNotNull(session);
    }

Works from a running service, but if I try to run unit tests, I get this error no matter what tweaks I try. This is about as simple a test class as I could make for demonstration purposes.

2022-09-22 11:59:12.174 ERROR 51030 --- [           main] g.d.e.DefaultDataFetcherExceptionHandler : Exception while executing data fetcher for /session: DgsReactiveRequestData not found

java.lang.IllegalStateException: DgsReactiveRequestData not found
	at com.netflix.graphql.dgs.reactive.internal.method.SyncHandlerMethodArgumentResolverAdapter.resolveArgument(SyncHandlerMethodArgumentResolverAdapter.kt:41) ~[graphql-dgs-reactive-5.2.2.jar:5.2.2]
	at com.netflix.graphql.dgs.internal.method.ArgumentResolverComposite.resolveArgument(ArgumentResolverComposite.kt:39) ~[graphql-dgs-5.2.2.jar:5.2.2]
	at com.netflix.graphql.dgs.internal.DataFetcherInvoker.get(DataFetcherInvoker.kt:62) ~[graphql-dgs-5.2.2.jar:5.2.2]
	at graphql.schema.DataFetcherFactories.lambda$wrapDataFetcher$2(DataFetcherFactories.java:37) ~[graphql-java-18.3.jar:na]
	at graphql.execution.ExecutionStrategy.fetchField(ExecutionStrategy.java:279) ~[graphql-java-18.3.jar:na]
	at graphql.execution.ExecutionStrategy.resolveFieldWithInfo(ExecutionStrategy.java:210) ~[graphql-java-18.3.jar:na]
	at graphql.execution.AsyncExecutionStrategy.execute(AsyncExecutionStrategy.java:60) ~[graphql-java-18.3.jar:na]
	at graphql.execution.Execution.executeOperation(Execution.java:159) ~[graphql-java-18.3.jar:na]
	at graphql.execution.Execution.execute(Execution.java:105) ~[graphql-java-18.3.jar:na]
	at graphql.GraphQL.execute(GraphQL.java:641) ~[graphql-java-18.3.jar:na]
	at graphql.GraphQL.lambda$parseValidateAndExecute$11(GraphQL.java:561) ~[graphql-java-18.3.jar:na]
	at java.base/java.util.concurrent.CompletableFuture.uniComposeStage(CompletableFuture.java:1187) ~[na:na]
	at java.base/java.util.concurrent.CompletableFuture.thenCompose(CompletableFuture.java:2309) ~[na:na]
	at graphql.GraphQL.parseValidateAndExecute(GraphQL.java:556) ~[graphql-java-18.3.jar:na]
	at graphql.GraphQL.executeAsync(GraphQL.java:524) ~[graphql-java-18.3.jar:na]
	at com.netflix.graphql.dgs.internal.BaseDgsQueryExecutor.baseExecute(BaseDgsQueryExecutor.kt:118) ~[graphql-dgs-5.2.2.jar:5.2.2]
	at com.netflix.graphql.dgs.internal.DefaultDgsQueryExecutor.execute(DefaultDgsQueryExecutor.kt:78) ~[graphql-dgs-5.2.2.jar:5.2.2]
	at com.netflix.graphql.dgs.DgsQueryExecutor.execute(DgsQueryExecutor.java:46) ~[graphql-dgs-5.2.2.jar:5.2.2]

Relevant data fetcher code:

    @DgsQuery
    public Mono<Session> session(@InputArgument final UUID uuid) {
        return sessionService.getSession(uuid);
    }

What am I missing?

[miles-po]

Someone saying, "I'm using DGS WebFlux and unit testing data fetchers without any errors," would also be helpful!

[cs-cbarber]

I know it's too late for the OP, but in case anybody else comes across this in a search:

Instead of

    @Autowired
    DgsQueryExecutor dgsQueryExecutor;

Use this in your unit tests of a DGS Reactive application:

    @Autowired
    DgsReactiveQueryExecutor dgsQueryExecutor;