Adds Flow extension for collecting values into a list. (0628dfba) · Commits · e / os / android_frameworks_base

packages/SystemUI/tests/utils/src/com/android/systemui/coroutines/Flow.kt

+46 −9

Original line number	Original line	Diff line number	Diff line
	@@ -14,6 +14,8 @@
	* limitations under the License.		* limitations under the License.
	*/		*/

			@file:Suppress("OPT_IN_USAGE")

	package com.android.systemui.coroutines		package com.android.systemui.coroutines

	import kotlin.coroutines.CoroutineContext		import kotlin.coroutines.CoroutineContext
	@@ -43,20 +45,55 @@ fun <T> TestScope.collectLastValue(
	context: CoroutineContext = EmptyCoroutineContext,		context: CoroutineContext = EmptyCoroutineContext,
	start: CoroutineStart = CoroutineStart.DEFAULT,		start: CoroutineStart = CoroutineStart.DEFAULT,
	): FlowValue<T?> {		): FlowValue<T?> {
	var lastValue: T? = null		val values by
	backgroundScope.launch(context, start) { flow.collect { lastValue = it } }		collectValues(
	return FlowValueImpl {		flow = flow,
			context = context,
			start = start,
			)
			return FlowValueImpl { values.lastOrNull() }
			}

			/**
			* Collect [flow] in a new [Job] and return a getter for the collection of values collected.
			*
			* ```
			* fun myTest() = runTest {
			* // ...
			* val values by collectValues(underTest.flow)
			* assertThat(values).isEqualTo(listOf(expected1, expected2, ...))
			* }
			* ```
			*/
			fun <T> TestScope.collectValues(
			flow: Flow<T>,
			context: CoroutineContext = EmptyCoroutineContext,
			start: CoroutineStart = CoroutineStart.DEFAULT,
			): FlowValues<T> {
			val values = mutableListOf<T>()
			backgroundScope.launch(context, start) { flow.collect(values::add) }
			return FlowValuesImpl {
	runCurrent()		runCurrent()
	lastValue		values.toList()
	}		}
	}		}

	/** @see collectLastValue */		/** @see collectLastValue */
	interface FlowValue<T> : ReadOnlyProperty<Any?, T?> {		interface FlowValue<T> : ReadOnlyProperty<Any?, T> {
	operator fun invoke(): T?		operator fun invoke(): T
			}

			/** @see collectValues */
			interface FlowValues<T> : ReadOnlyProperty<Any?, List<T>> {
			operator fun invoke(): List<T>
			}

			private class FlowValueImpl<T>(private val block: () -> T) : FlowValue<T> {
			override operator fun invoke(): T = block()
			override fun getValue(thisRef: Any?, property: KProperty<*>): T = invoke()
	}		}

	private class FlowValueImpl<T>(private val block: () -> T?) : FlowValue<T> {		private class FlowValuesImpl<T>(private val block: () -> List<T>) : FlowValues<T> {
	override operator fun invoke(): T? = block()		override operator fun invoke(): List<T> = block()
	override fun getValue(thisRef: Any?, property: KProperty<*>): T? = invoke()		override fun getValue(thisRef: Any?, property: KProperty<*>): List<T> = invoke()
	}		}