How to use JUnit to test asynchronous processes

Question

How do you test methods that fire asynchronous processes with JUnit?

I don\'t know how to make my test wait for the process to end (it is not exactly a unit test, it

Answer 1

Let's say you have this code:

public void method() {
        CompletableFuture.runAsync(() -> {
            //logic
            //logic
            //logic
            //logic
        });
    }

Try to refactor it to something like this:

public void refactoredMethod() {
    CompletableFuture.runAsync(this::subMethod);
}

private void subMethod() {
    //logic
    //logic
    //logic
    //logic
}

After that, test the subMethod this way:

org.powermock.reflect.Whitebox.invokeMethod(classInstance, "subMethod"); 

This isn't a perfect solution, but it tests all the logic inside your async execution.