Question

我正在从该页面学习Reactive Programming：tutorial。我想知道为什么在下面的示例中，当我期望4？

时，stact trace会在实际的一条记录中引发错误

java.lang.AssertionError: expectation "expectNextCount(4)" failed (expected: count = 4; actual: counted = 1; signal: onComplete())

// TODO Create a StepVerifier that initially requests all values and expect 4 values to be received
StepVerifier requestAllExpectFour(Flux<User> flux) {
        return StepVerifier.withVirtualTime(() -> Flux.just(flux))
                .expectSubscription()
                .thenRequest(4)
                .expectNextCount(4)
                .expectComplete();
}

我想知道我在这里是否遗漏了什么。

Answer 1

试试这个

StepVerifier requestAllExpectFour(Flux<User> flux) {
    return StepVerifier.withVirtualTime(() -> flux)
            .expectSubscription() 
            .thenRequest(Long.MAX_VALUE) 
            .expectNextCount(4) 
            .expectComplete(); 
}

或者像这样

StepVerifier requestAllExpectFour(Flux<User> flux) {
    return StepVerifier.create(flux)
            .expectSubscription() 
            .thenRequest(Long.MAX_VALUE) 
            .expectNextCount(4) 
            .expectComplete(); 
}

Answer 2

源代码 - ＆gt; https://github.com/reactor/lite-rx-api-hands-on

问题 - ＆gt; https://github.com/reactor/reactor-addons/issues/61

指南 - ＆gt; https://projectreactor.io/docs/core/release/reference/#_manipulating_time

以及下面的代码有效......

StepVerifier requestAllExpectFour(Flux<User> flux) {
    List<User> users = new ArrayList<>(Arrays.asList(User.SKYLER, User.JESSE, User.WALTER, User.SAUL));
    return StepVerifier.withVirtualTime(() -> 
                Flux.interval(Duration.ofMillis(100))
                   .zipWith(Flux.fromIterable(users), (i, user) -> user))
            .expectSubscription()  
            .thenRequest(4) 
            .thenAwait(Duration.ofMillis(400))
            .expectNextCount(4)  
        .expectComplete();  
}

Answer 3

我认为问题在于您正在通过使用Flux.just向焊剂提供单次发射的焊剂。您可以只应用助焊剂本身：

.withVirtualTime(() -> flux)

Answer 4

我猜这个练习想要的是你使用构造函数使用请求初始化 StepVerifier，就像这样：

StepVerifier requestAllExpectFour(Flux<User> flux) {
    return StepVerifier.create(flux, 4)
          .expectNextCount(4)
          .expectComplete();
}

使用StepVerifier测试通量

4 个答案: