Writing imperative code in Project Reactor

I have a class with the following two methods.

public class Test1 {
    public Mono<String> blah1() {
        Mono<String> blah = Mono.just("blah1");
        try {
            Thread.sleep(5000);
        } catch (InterruptedException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        System.out.println("blah1 done");
        return blah;
    }
    
    public Mono<String> blah2() {
        Mono<String> blah = Mono.just("blah2");
        try {
            Thread.sleep(1000);
        } catch (InterruptedException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        System.out.println("blah2 done");
        return blah;
    }
}

I have the following JUnit:

@Test
public void blah1Test() {
    Flux<Tuple2<String, String>> s = Flux.zip(test1.blah1(), test1.blah2());    
}

My result is as follows:

blah1 done
blah2 done

I expect blah2 to finish before blah1. Thus I believe this is processing blocking instead of non blocking. What do I need to do to have the output switch to blah2 done then blah1 done? Basically why are these not processing in parallel?

Thanks in advance for your time!

Both sleep and println are executed outside the reactive pipeline. Therefore, both blah1() and blah2() behave like regular, non-reactive methods.

Try this:

public Mono<String> blah1() {
    System.out.println("blah1 start");
    return Mono.just("blah1")
        .delayElement(Duration.ofMillis(5000))
        .doOnNext(e -> System.out.println("blah1 done"));
}

public Mono<String> blah2() {
    System.out.println("blah2 start");
    return Mono.just("blah2")
        .delayElement(Duration.ofMillis(1000))
        .doOnNext(e -> System.out.println("blah2 done"));
}

Here, we have the expected result because printing takes place within the reactive pipeline.

Output:

blah1  start 
blah2 start 
blah2 done
blah1 done