How about naming this AchievementAnimationState and AchievementAnimationState.Animating AchievementAnimationState.NotAnimating?

The namings look better. I will rename them.

We would like to promote the best practice that a StateHolder should be notified events.
So how about naming this onAchivementClicked and judge if we run a animation in ViewModel for showAnimation?
And use "onAnimationFinished" as a name for finishAnimation?

Renamed showAnimation to onAchivementClick and finishAnimation to onAnimationFinish.

Could you change this name as we change the state? 🙇

Sorry for overlooking. I renamed clickedAchievement to achievementAnimationState.

Maybe you should restore the executor after test to isolate the tests 👀

@takahirom
I've checked if this setup affects other test classes.
To invesigate that, I created AchievementsScreenTest2 copying original one except setUp function. As a result, all the test cases in AchievementsScreenTest2 didn't capture achivement highlight correctly because LottieTask.EXECUTOR was not set up for tests.
So, I assume changing LottieTask.EXECUTOR is confined in its test class and tearDown isn't really necessary.
However, if you are concerned about other test cases in the same test class, which doesn't need to set up LottieTask.EXECUTOR, I'd make setup in each test cases like below. But I feel it's kind of hacky.

fun checkHighlightImageA() {
    achievementsScreenRobot {
        LottieTask.EXECUTOR = Executor(Runnable::run)
        setupSavedAchievement(ArcticFox)
        setupScreenContent()
        clickAchievementImageA()
        checkScreenCapture()
        LottieTask.EXECUTOR = Executors.newCachedThreadPool()
    }
}

As far as I know static variable is used across the tests. We have some options to do it.
How about adding it here?

@takahirom
I wasn't aware of that system.
I added LottieTestRule.