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Test animations Stay organized with collections Save and categorize content based on your preferences.

Compose offers ComposeTestRule that lets you write tests for animations in a deterministic manner with full control over the test clock. This lets you verify intermediate animation values. In addition, a test can run quicker than the actual duration of the animation.

ComposeTestRule exposes its test clock as mainClock. You can set the autoAdvance property to false to control the clock in your test code. After initiating the animation you want to test, the clock can be moved forward with advanceTimeBy.

One thing to note here is that advanceTimeBy doesn't move the clock exactly by the specified duration. Rather, it rounds it up to the nearest duration that is a multiplier of the frame duration.

@get:Rule
val rule = createComposeRule()

@Test
fun testAnimationWithClock() {
    // Pause animations
    rule.mainClock.autoAdvance = false
    var enabled by mutableStateOf(false)
    rule.setContent {
        val color by animateColorAsState(
            targetValue = if (enabled) Color.Red else Color.Green,
            animationSpec = tween(durationMillis = 250)
        )
        Box(Modifier.size(64.dp).background(color))
    }

    // Initiate the animation.
    enabled = true

    // Let the animation proceed.
    rule.mainClock.advanceTimeBy(50L)

    // Compare the result with the image showing the expected result.
    // `assertAgainGolden` needs to be implemented in your code.
    rule.onRoot().captureToImage().assertAgainstGolden()
}

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Last updated 2026-08-14 UTC.

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