Expected a completion event, but didn't received it

[softshipper]

Hi all,
I use Mutiny in combination with https://quarkus.io/guides/reactive-sql-clients.
When I do the following query to the database with the assertion:

    @Test
    public void test1() {
        var tester = client.query("SELECT * FROM company")
                .execute()
                .map(pgRowSet -> pgRowSet.iterator().next().getString("open_id"))
                .subscribe()
                .withSubscriber(UniAssertSubscriber.create());

        tester.awaitSubscription(Duration.ofSeconds(3))
                .assertCompleted()
                .assertItem("AUTH2");

    }

I have got:

Expected a completion event, but didn't received it.
java.lang.AssertionError: 
Expected a completion event, but didn't received it.
	at io.smallrye.mutiny.helpers.test.AssertionHelper.fail(AssertionHelper.java:146)
	at io.smallrye.mutiny.helpers.test.AssertionHelper.shouldHaveCompleted(AssertionHelper.java:24)
	at io.smallrye.mutiny.helpers.test.UniAssertSubscriber.assertCompleted(UniAssertSubscriber.java:315)
	at io.acme.ExampleResourceTest.test1(ExampleResourceTest.java:26)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)

Unfortunately, I could not figure out why I do not receive the completion event.

Calling the method await instead of subscribe it yields the expected result:

    @Test
    public void test2() {
        var tester = client.query("SELECT * FROM company")
                .execute()
                .map(pgRowSet -> pgRowSet.iterator().next().getString("open_id"))
                .await()
                .atMost(Duration.ofSeconds(3));

        Assertions.assertEquals(tester, "AUTH2");
    }

What is wrong with subscribe?

Best regards

[quarkus-bot[bot]]

/cc @evanchooly, @geoand

[geoand]

cc @tsegismont @jponge

[jponge]

When you call subscribe().withSubscriber(...) then you do subscribe to the pipeline and trigger the database access... but the underlying operations are asynchronous.

Here you await for a subscription for up to 3 seconds, which is fine, but you have no guarantee that once you have a subscription you immediately have the item, hence the test fails.

By contrast the .await().atMost(...) call awaits for the item, which is correct.

If you want to keep the first form you should look into awaitItems.