public class TestMonotonicFrameClock(
private val coroutineScope: CoroutineScope,
@get:Suppress("MethodNameUnits") // Nanos for high-precision animation clocks
public val frameDelayNanos: Long = DefaultFrameDelay,
private val onPerformTraversals: (Long) -> Unit = {},
) : MonotonicFrameClockA 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.
Parameters
| coroutineScope | The CoroutineScope used to simulate the main thread and schedule frames on. It must contain a TestCoroutineScheduler and a ContinuationInterceptor. |
| frameDelayNanos | The number of nanoseconds to delay between executing frames. |
| onPerformTraversals | 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. |
Properties
hasAwaiters
public val hasAwaiters: BooleanReturns whether there are any awaiters on this clock.
continuationInterceptor
public val continuationInterceptor: ContinuationInterceptorA 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.
Functions
withFrameNanos
override suspend fun <R> withFrameNanos(onFrame: (frameTimeNanos: Long) -> R): RSchedules 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.
