Can any explain why this code fails with “java.lang.AssertionError: Expected value Hey for key OID, key not present”:

    @Test
    void name() {
        StepVerifier.create(Mono.just("Start")
                        .map(val -> Optional.of(val)).defaultIfEmpty(Optional.empty()) // <---- point of interest 1
                        .flatMap(val -> Mono.just(val).then().contextWrite(ctx -> ctx.put(OID, "Hey"))))
                .expectAccessibleContext()
                .contains("OID", "Hey") // <---- point of interest 2
                .then()
                .verifyComplete();
    }

The flatMap is never executed.

The code succeeds if I’m removing “point of interest 1”:

    @Test
    void name() {
        StepVerifier.create(Mono.just("Start")
                        .flatMap(val -> Mono.just(val).then().contextWrite(ctx -> ctx.put(OID, "Hey"))))
                .expectAccessibleContext()
                .contains("OID", "Hey") // <---- point of interest 2
                .then()
                .verifyComplete();
    }

My clear idea is that expectAccessibleContext() may be what causes this odd behaviour. But I don’t have any good reason why.

StepVerifier to succeed