TestMonotonicFrameClock

Added in 1.0.0

android

@ExperimentalCoroutinesApi
@ExperimentalTestApi
class TestMonotonicFrameClock : MonotonicFrameClock

A MonotonicFrameClock with a time source controlled by a kotlinx-coroutines-test TestCoroutineScheduler. This frame clock may be used to consistently drive time under controlled tests.

Calls to withFrameNanos will schedule an upcoming frame frameDelayNanos nanoseconds in the future by launching into coroutineScope if such a frame has not yet been scheduled. The current frame time for withFrameNanos is provided by delayController. It is strongly suggested that coroutineScope contain the test dispatcher controlled by delayController.

Summary

Public constructors
`TestMonotonicFrameClock( coroutineScope: CoroutineScope, frameDelayNanos: Long, onPerformTraversals: (Long) -> Unit )`	android

Public functions
`open suspend R`	`<R : Any?> withFrameNanos(onFrame: (frameTimeNanos: Long) -> R)` Schedules `onFrame` to be ran on the next "fake" frame, and schedules the task to actually perform that frame if it hasn't already been scheduled.	android

Public properties
`ContinuationInterceptor`	`@ExperimentalTestApi continuationInterceptor` A `CoroutineDispatcher` that will defer continuation resumptions requested within `withFrameNanos` calls to until after the frame callbacks have finished running.	android
`Long`	`frameDelayNanos` The number of nanoseconds to `delay` between executing frames.	android
`Boolean`	`hasAwaiters` Returns whether there are any awaiters on this clock.	android

Extension properties
`Long`	`@ExperimentalTestApi TestMonotonicFrameClock.frameDelayMillis` The frame delay time for the `TestMonotonicFrameClock` in milliseconds.	android

Inherited functions

From kotlin.coroutines.CoroutineContext

open operator CoroutineContext

plus(context: CoroutineContext)

android

From kotlin.coroutines.CoroutineContext.Element

`open R`	`<R : Any?> fold(initial: R, operation: (CoroutineContext.Element, R) -> R)`	android
`open operator E?`	`<E : CoroutineContext.Element> get(key: CoroutineContext.Key<E>)`	android
`open CoroutineContext`	`minusKey(key: CoroutineContext.Key<*>)`	android

Inherited properties

From androidx.compose.runtime.MonotonicFrameClock

open CoroutineContext.Key<*>

key

android

Public constructors

TestMonotonicFrameClock

android

Added in 1.4.0

TestMonotonicFrameClock(
    coroutineScope: CoroutineScope,
    frameDelayNanos: Long = DefaultFrameDelay,
    onPerformTraversals: (Long) -> Unit = {}
)

Parameters
`coroutineScope: CoroutineScope`	The `CoroutineScope` used to simulate the main thread and schedule frames on. It must contain a `TestCoroutineScheduler` and a `ContinuationInterceptor`.
`frameDelayNanos: Long = DefaultFrameDelay`	The number of nanoseconds to `delay` between executing frames.
`onPerformTraversals: (Long) -> Unit = {}`	Called with the frame time of the frame that was just executed, after running all `withFrameNanos` callbacks, but before resuming their callers' continuations. Any continuations resumed while running frame callbacks or `onPerformTraversals` will not be dispatched until after `onPerformTraversals` finishes. If `onPerformTraversals` throws, all `withFrameNanos` callers will be cancelled.

Public functions

withFrameNanos

android

open suspend fun <R : Any?> withFrameNanos(onFrame: (frameTimeNanos: Long) -> R): R

Schedules onFrame to be ran on the next "fake" frame, and schedules the task to actually perform that frame if it hasn't already been scheduled.

Instead of waiting for a vsync message to perform the next frame, it simply calls the coroutine delay function for the test frame time frameDelayMillis (which the underlying test coroutine scheduler will actually complete immediately without waiting), and then run all scheduled tasks.

Public properties

continuationInterceptor

android

Added in 1.4.0

@ExperimentalTestApi
val continuationInterceptor: ContinuationInterceptor

A CoroutineDispatcher that will defer continuation resumptions requested within withFrameNanos calls to until after the frame callbacks have finished running. Resumptions will then be dispatched before resuming the continuations from the withFrameNanos calls themselves.

frameDelayNanos

android

Added in 1.0.0

val frameDelayNanos: Long

The number of nanoseconds to delay between executing frames.

hasAwaiters

android

Added in 1.0.0

val hasAwaiters: Boolean

Returns whether there are any awaiters on this clock.

Extension properties

frameDelayMillis

android

Artifact: androidx.compose.ui:ui-test

View Source

@ExperimentalTestApi
val TestMonotonicFrameClock.frameDelayMillis: Long

The frame delay time for the TestMonotonicFrameClock in milliseconds.