Test animations
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Compose offers ComposeTestRule
that allows you to write tests for animations
in a deterministic manner with full control over the test clock. This allows you
to 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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Content and code samples on this page are subject to the licenses described in the Content License. Java and OpenJDK are trademarks or registered trademarks of Oracle and/or its affiliates.
Last updated 2025-08-26 UTC.
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Missing the information I need","missingTheInformationINeed","thumb-down"],["Too complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-26 UTC."],[],[],null,["Compose offers `ComposeTestRule` that allows you to write tests for animations\nin a deterministic manner with full control over the test clock. This allows you\nto verify intermediate animation values. In addition, a test can run quicker\nthan the actual duration of the animation.\n\n`ComposeTestRule` exposes its test clock as `mainClock`. You can set the\n`autoAdvance` property to false to control the clock in your test code. After\ninitiating the animation you want to test, the clock can be moved forward with\n`advanceTimeBy`.\n\nOne thing to note here is that `advanceTimeBy` doesn't move the clock exactly by\nthe specified duration. Rather, it rounds it up to the nearest duration that is\na multiplier of the frame duration.\n\n\n```kotlin\n@get:Rule\nval rule = createComposeRule()\n\n@Test\nfun testAnimationWithClock() {\n // Pause animations\n rule.mainClock.autoAdvance = false\n var enabled by mutableStateOf(false)\n rule.setContent {\n val color by animateColorAsState(\n targetValue = if (enabled) Color.Red else Color.Green,\n animationSpec = tween(durationMillis = 250)\n )\n Box(Modifier.size(64.dp).background(color))\n }\n\n // Initiate the animation.\n enabled = true\n\n // Let the animation proceed.\n rule.mainClock.advanceTimeBy(50L)\n\n // Compare the result with the image showing the expected result.\n // `assertAgainGolden` needs to be implemented in your code.\n rule.onRoot().captureToImage().assertAgainstGolden()\n}https://github.com/android/snippets/blob/5673ffc60b614daf028ee936227128eb8c4f9781/compose/snippets/src/androidTest/java/com/example/compose/snippets/animation/AnimationTestingSnippets.kt#L57-L82\n```\n\n\u003cbr /\u003e\n\nRecommended for you\n\n- Note: link text is displayed when JavaScript is off\n- [Testing your Compose layout](/develop/ui/compose/testing)\n- [Other considerations](/develop/ui/compose/migrate/other-considerations)\n- [Customize animations {:#customize-animations}](/develop/ui/compose/animation/customize)"]]