Clarify usage of CircuitBreaker with Reactor

I am evaluating resilience4j for use in a project in which we using Reactor 3. I think that I am misunderstanding how the CircuitBreaker works, but I cannot find any clarity in the documentation.

Here is a simple test case (written in Groovy using Spock):

def "test CircuitBreaker"() {
        given: "a Flux which emits one exception protected by a circuitBreaker"
        def aCircuitBreakerConfig = CircuitBreakerConfig.custom()
                .waitDurationInOpenState(Duration.ofSeconds(5))
                .ringBufferSizeInClosedState(3)
                .ringBufferSizeInHalfOpenState(1)
                .failureRateThreshold(50.0)
                .build()
        def circuitBreakerRegistry = CircuitBreakerRegistry.of(aCircuitBreakerConfig)
        def circuitBreaker = circuitBreakerRegistry.circuitBreaker("testCB")
        def testFlux = Flux.just(new RuntimeException(), 0L, 3L, 6L, 9L)
                .transform(CircuitBreakerOperator.of(circuitBreaker)).log()

        when: "the Flux is subscribed"
        StepVerifier.create(testFlux)
                .expectSubscription()
                .expectNext(0L)
                .expectNext(3L)
                .expectNext(6L)
                .expectNext(9L)
                .verifyComplete()

        then: "it correctly emits four values and then completes"
        notThrown(Throwable)
    }

What I expected was that the circuitBreaker would drop the exception, adding the error bit to the ring buffer, and continue operation with the next element in the Flux. Instead the exception is passed on, and the test fails.

Can someone please clarify the behavior of a CircuitBreaker when applied to a Reactor 3 Flux. Does it always pass on errors until transitioning to the Open state, or is there a way to have it simply drop the error (similar to onErrorContinue)?

[RobWin]

It has been replaced a while ago but CallNotPermittedException

[HabeebCycle]

Thanks bro!