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Commit 1bbbc897 authored by Lucas Silva's avatar Lucas Silva
Browse files

Ensure boolean flow helpers only emit when value changes 

Currently these helpers are emitting each time the underlying flows
emit, even if the value doesn't change.

Bug: 333774684
Test: atest BooleanFlowOperatorsTest
Flag: N/A
Change-Id: I10d713373c7f05d856cf1462796c30b1e406ff36
parent 8fecf6ff

packages/SystemUI/multivalentTests/src/com/android/systemui/util/kotlin/BooleanFlowOperatorsTest.kt

+31 −0
Original line number Diff line number Diff line
@@ -20,6 +20,7 @@ import androidx.test.ext.junit.runners.AndroidJUnit4 
import androidx.test.filters.SmallTest

import com.android.systemui.SysuiTestCase

import com.android.systemui.coroutines.collectLastValue

import com.android.systemui.coroutines.collectValues

import com.android.systemui.kosmos.testScope

import com.android.systemui.testKosmos

import com.android.systemui.util.kotlin.BooleanFlowOperators.and
@@ -27,6 +28,7 @@ import com.android.systemui.util.kotlin.BooleanFlowOperators.not 
import com.android.systemui.util.kotlin.BooleanFlowOperators.or

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

import kotlinx.coroutines.flow.Flow

import kotlinx.coroutines.flow.MutableStateFlow

import kotlinx.coroutines.flow.flowOf

import kotlinx.coroutines.test.runTest

import org.junit.Test
@@ -61,6 +63,21 @@ class BooleanFlowOperatorsTest : SysuiTestCase() { 
            assertThat(result).isFalse()

        }



    @Test

    fun and_onlyEmitsWhenValueChanges() =

        testScope.runTest {

            val flow1 = MutableStateFlow(false)

            val flow2 = MutableStateFlow(false)

            val values by collectValues(and(flow1, flow2))



            assertThat(values).containsExactly(false)

            flow1.value = true

            // Overall value is still false, we should not have emitted again.

            assertThat(values).containsExactly(false)

            flow2.value = true

            assertThat(values).containsExactly(false, true).inOrder()

        }



    @Test

    fun or_allTrue_returnsTrue() =

        testScope.runTest {
@@ -82,6 +99,20 @@ class BooleanFlowOperatorsTest : SysuiTestCase() { 
            assertThat(result).isFalse()

        }



    @Test

    fun or_onlyEmitsWhenValueChanges() =

        testScope.runTest {

            val flow1 = MutableStateFlow(false)

            val flow2 = MutableStateFlow(false)

            val values by collectValues(or(flow1, flow2))



            assertThat(values).containsExactly(false)

            flow1.value = true

            assertThat(values).containsExactly(false, true).inOrder()

            flow2.value = true

            assertThat(values).containsExactly(false, true).inOrder()

        }



    @Test

    fun not_true_returnsFalse() =

        testScope.runTest {

packages/SystemUI/src/com/android/systemui/util/kotlin/BooleanFlowOperators.kt

+3 −2
Original line number Diff line number Diff line
@@ -18,6 +18,7 @@ package com.android.systemui.util.kotlin 


import kotlinx.coroutines.flow.Flow

import kotlinx.coroutines.flow.combine

import kotlinx.coroutines.flow.distinctUntilChanged

import kotlinx.coroutines.flow.map



object BooleanFlowOperators {
@@ -31,7 +32,7 @@ object BooleanFlowOperators { 
     * ```

     */

    fun and(vararg flows: Flow<Boolean>): Flow<Boolean> =

        combine(flows.asIterable()) { values -> values.all { it } }

        combine(flows.asIterable()) { values -> values.all { it } }.distinctUntilChanged()



    /**

     * Logical NOT operator for a boolean flow.
@@ -48,5 +49,5 @@ object BooleanFlowOperators { 
     * determine the result.

     */

    fun or(vararg flows: Flow<Boolean>): Flow<Boolean> =

        combine(flows.asIterable()) { values -> values.any { it } }

        combine(flows.asIterable()) { values -> values.any { it } }.distinctUntilChanged()

}