AndroidAnimationClockTestRule.kt
/*
* Copyright 2020 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package androidx.compose.ui.test.junit4
import androidx.compose.animation.core.InternalAnimationApi
import androidx.compose.animation.core.rootAnimationClockFactory
import androidx.compose.ui.test.ExperimentalTesting
import androidx.compose.ui.test.TestAnimationClock
import androidx.test.espresso.IdlingResource
import androidx.compose.ui.test.junit4.android.registerTestClock
import androidx.compose.ui.test.junit4.android.unregisterTestClock
import androidx.compose.ui.test.junit4.android.AndroidTestAnimationClock
import org.junit.rules.TestRule
import org.junit.runner.Description
import org.junit.runners.model.Statement
/**
* A [TestRule] to monitor and take over the animation clock in the composition. It substitutes
* the ambient animation clock provided at the root of the composition tree with a
* [TestAnimationClock] and registers it with [registerTestClock].
*
* Usually you don't need to create this rule by yourself, it is done for you in
* [ComposeTestRule]. If you don't use [ComposeTestRule], use this rule in your test and make
* sure it is run _before_ your activity is created.
*
* If your app provides a custom animation clock somewhere in your composition, make sure to have
* it implement [TestAnimationClock] and register it with [registerTestClock]. Alternatively,
* if you use Espresso you can create your own [IdlingResource] to let Espresso await your
* animations. Otherwise, built in steps that make sure the UI is stable when performing actions
* or assertions will fail to work.
*/
@ExperimentalTesting
internal class AndroidAnimationClockTestRule : AnimationClockTestRule {
/** Backing property for [clock] */
private val _clock = AndroidTestAnimationClock()
/**
* The ambient animation clock that is provided at the root of the composition tree.
* Typically, apps will only use this clock. If your app provides another clock in the tree,
* make sure to let it implement [TestAnimationClock] and register it with
* [registerTestClock].
*/
override val clock: TestAnimationClock get() = _clock
override fun apply(base: Statement, description: Description?): Statement {
return AnimationClockStatement(base)
}
@OptIn(InternalAnimationApi::class)
private inner class AnimationClockStatement(private val base: Statement) : Statement() {
override fun evaluate() {
val oldFactory = rootAnimationClockFactory
registerTestClock(clock)
rootAnimationClockFactory = { clock }
try {
base.evaluate()
} finally {
try {
_clock.dispose()
} finally {
rootAnimationClockFactory = oldFactory
unregisterTestClock(clock)
}
}
}
}
}
@ExperimentalTesting
actual fun createAnimationClockRule(): AnimationClockTestRule =
AndroidAnimationClockTestRule()