@Test
public void testExternalActionMonoError() throws InterruptedException {

    newReconcilerWithRegistrations(current -> Collections.emptyList(), "r1", "a");
    try {
        reconciler.apply("r1", anything -> Mono.error(new RuntimeException("simulated error"))).block();
        fail("Expected error");
    } catch (Exception e) {
        assertThat(e).isInstanceOf(RuntimeException.class);
        assertThat(e.getMessage()).isEqualTo("simulated error");
    }
    assertThat(changesSubscriber.takeNext()).isNull();
}