Merge "Add helper to convert a kotlin flow to a Condition" into udc-dev

package com.android.systemui.shared.condition

import kotlinx.coroutines.CoroutineScope

import kotlinx.coroutines.Job

import kotlinx.coroutines.flow.Flow

import kotlinx.coroutines.launch

/** Converts a boolean flow to a [Condition] object which can be used with a [Monitor] */

@JvmOverloads

fun Flow<Boolean>.toCondition(scope: CoroutineScope, initialValue: Boolean? = null): Condition {

    return object : Condition(initialValue, false) {

        var job: Job? = null

        override fun start() {

            job = scope.launch { collect { updateCondition(it) } }

        }

        override fun stop() {

            job?.cancel()

            job = null

        }

    }

}

package com.android.systemui.shared.condition

import android.testing.AndroidTestingRunner

import androidx.test.filters.SmallTest

import com.android.systemui.SysuiTestCase

import com.google.common.truth.Truth.assertThat

import kotlinx.coroutines.ExperimentalCoroutinesApi

import kotlinx.coroutines.flow.MutableSharedFlow

import kotlinx.coroutines.flow.MutableStateFlow

import kotlinx.coroutines.flow.emptyFlow

import kotlinx.coroutines.flow.flowOf

import kotlinx.coroutines.test.StandardTestDispatcher

import kotlinx.coroutines.test.TestScope

import kotlinx.coroutines.test.runCurrent

import kotlinx.coroutines.test.runTest

import org.junit.Before

import org.junit.Test

import org.junit.runner.RunWith

@OptIn(ExperimentalCoroutinesApi::class)

@SmallTest

@RunWith(AndroidTestingRunner::class)

class ConditionExtensionsTest : SysuiTestCase() {

    private lateinit var testScope: TestScope

    @Before

    fun setUp() {

        testScope = TestScope(StandardTestDispatcher())

    }

    @Test

    fun flowInitiallyTrue() =

        testScope.runTest {

            val flow = flowOf(true)

            val condition = flow.toCondition(this)

            runCurrent()

            assertThat(condition.isConditionSet).isFalse()

            condition.start()

            runCurrent()

            assertThat(condition.isConditionSet).isTrue()

            assertThat(condition.isConditionMet).isTrue()

        }

    @Test

    fun flowInitiallyFalse() =

        testScope.runTest {

            val flow = flowOf(false)

            val condition = flow.toCondition(this)

            runCurrent()

            assertThat(condition.isConditionSet).isFalse()

            condition.start()

            runCurrent()

            assertThat(condition.isConditionSet).isTrue()

            assertThat(condition.isConditionMet).isFalse()

        }

    @Test

    fun emptyFlowWithNoInitialValue() =

        testScope.runTest {

            val flow = emptyFlow<Boolean>()

            val condition = flow.toCondition(this)

            condition.start()

            runCurrent()

            assertThat(condition.isConditionSet).isFalse()

            assertThat(condition.isConditionMet).isFalse()

        }

    @Test

    fun emptyFlowWithInitialValueOfTrue() =

        testScope.runTest {

            val flow = emptyFlow<Boolean>()

            val condition = flow.toCondition(scope = this, initialValue = true)

            condition.start()

            runCurrent()

            assertThat(condition.isConditionSet).isTrue()

            assertThat(condition.isConditionMet).isTrue()

        }

    @Test

    fun emptyFlowWithInitialValueOfFalse() =

        testScope.runTest {

            val flow = emptyFlow<Boolean>()

            val condition = flow.toCondition(scope = this, initialValue = false)

            condition.start()

            runCurrent()

            assertThat(condition.isConditionSet).isTrue()

            assertThat(condition.isConditionMet).isFalse()

        }

    @Test

    fun conditionUpdatesWhenFlowEmitsNewValue() =

        testScope.runTest {

            val flow = MutableStateFlow(false)

            val condition = flow.toCondition(this)

            condition.start()

            runCurrent()

            assertThat(condition.isConditionSet).isTrue()

            assertThat(condition.isConditionMet).isFalse()

            flow.value = true

            runCurrent()

            assertThat(condition.isConditionMet).isTrue()

            flow.value = false

            runCurrent()

            assertThat(condition.isConditionMet).isFalse()

            condition.stop()

        }

    @Test

    fun stoppingConditionUnsubscribesFromFlow() =

        testScope.runTest {

            val flow = MutableSharedFlow<Boolean>()

            val condition = flow.toCondition(this)

            runCurrent()

            assertThat(flow.subscriptionCount.value).isEqualTo(0)

            condition.start()

            runCurrent()

            assertThat(flow.subscriptionCount.value).isEqualTo(1)

            condition.stop()

            runCurrent()

            assertThat(flow.subscriptionCount.value).isEqualTo(0)

        }

}