Mocking/skipping sleep calls in unit tests-CodePudding

What is the general approach in unit tests for methods that involve a sleep() call?

Lets say I have the class:

class Foo {
    public bool someMethodWithSleep() {
        bool failed = false;

        for (int i = 0 : 5) {
            failed = trySomething(); // mocked to return false
            if (failed) {
                TimeUnit.SECONDS.sleep(5);
            } else { return true; }
        }
        return false;
    }
}

In test cases for failures that call this function (directly or nested), I dont want it to sleep for 25 seconds and slowing every test file that calls it. What's the best approach to skip the sleep calls in unit tests?

CodePudding user response：

Replace it with a dependency.

class Foo {
    private final Sleeper sleeper;
    public Foo(final Sleeper sleeper) {
        this.sleeper = sleeper;
    }
    public Foo() {
        this(SecondsSleeper.INSTANCE);
    }

    public bool someMethodWithSleep() {
        bool failed = false;

        for (int i = 0 : 5) {
            failed = trySomething(); // mocked to return false
            if (failed) {
                sleeper.sleep(5);
            } else { return true; }
        }
        return false;
    }
}
interface Sleeper {
  void sleep(int duration);
}
enum SecondsSleeper implements Sleeper {
  INSTANCE;
  void sleep(final int seconds) {
    TimeUnit.SECONDS.sleep(seconds);
  }
}
enum TestSleeper implements Sleeper {
  INSTANCE;
  void sleepSeconds(final int duration) {
    // do nothing
  }
}

Then in your real application, create Foo as new Foo() and in your test as new Foo(TestSleeper.INSTANCE)