| /* |
| * 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.paging |
| |
| import androidx.paging.LoadState.NotLoading |
| import androidx.paging.LoadType.PREPEND |
| import androidx.paging.PageEvent.Drop |
| import androidx.paging.PageEvent.Insert.Companion.Append |
| import androidx.paging.PageEvent.Insert.Companion.Prepend |
| import androidx.paging.PageEvent.Insert.Companion.Refresh |
| import androidx.testutils.MainDispatcherRule |
| import com.google.common.truth.Truth.assertThat |
| import kotlinx.coroutines.CoroutineDispatcher |
| import kotlinx.coroutines.ExperimentalCoroutinesApi |
| import kotlinx.coroutines.channels.Channel |
| import kotlinx.coroutines.flow.collect |
| import kotlinx.coroutines.flow.consumeAsFlow |
| import kotlinx.coroutines.flow.flow |
| import kotlinx.coroutines.flow.flowOf |
| import kotlinx.coroutines.launch |
| import kotlinx.coroutines.suspendCancellableCoroutine |
| import kotlinx.coroutines.test.TestCoroutineScope |
| import kotlinx.coroutines.test.runBlockingTest |
| import org.junit.Rule |
| import org.junit.Test |
| import org.junit.runner.RunWith |
| import org.junit.runners.JUnit4 |
| import kotlin.coroutines.ContinuationInterceptor |
| import kotlin.test.assertEquals |
| import kotlin.test.assertFalse |
| import kotlin.test.assertNull |
| import kotlin.test.assertTrue |
| |
| @OptIn(ExperimentalCoroutinesApi::class, ExperimentalPagingApi::class) |
| @RunWith(JUnit4::class) |
| class PagingDataDifferTest { |
| private val testScope = TestCoroutineScope() |
| |
| @get:Rule |
| val dispatcherRule = MainDispatcherRule( |
| testScope.coroutineContext[ContinuationInterceptor] as CoroutineDispatcher |
| ) |
| |
| @Test |
| fun collectFrom_static() = testScope.runBlockingTest { |
| pauseDispatcher { |
| val differ = SimpleDiffer(dummyDifferCallback) |
| val receiver = object : UiReceiver { |
| val hintsAdded = mutableListOf<ViewportHint>() |
| var didRetry = false |
| var didRefresh = false |
| |
| override fun addHint(hint: ViewportHint) { |
| hintsAdded.add(hint) |
| } |
| |
| override fun retry() { |
| didRetry = true |
| } |
| |
| override fun refresh() { |
| didRefresh = true |
| } |
| } |
| |
| val job1 = launch { |
| differ.collectFrom(infinitelySuspendingPagingData(receiver)) |
| } |
| advanceUntilIdle() |
| job1.cancel() |
| |
| val job2 = launch { |
| differ.collectFrom(PagingData.empty()) |
| } |
| advanceUntilIdle() |
| job2.cancel() |
| |
| // Static replacement should also replace the UiReceiver from previous generation. |
| differ.retry() |
| differ.refresh() |
| advanceUntilIdle() |
| |
| assertFalse { receiver.didRetry } |
| assertFalse { receiver.didRefresh } |
| } |
| } |
| |
| @Test |
| fun collectFrom_twice() = testScope.runBlockingTest { |
| val differ = SimpleDiffer(dummyDifferCallback) |
| |
| launch { differ.collectFrom(infinitelySuspendingPagingData()) } |
| .cancel() |
| launch { differ.collectFrom(infinitelySuspendingPagingData()) } |
| .cancel() |
| } |
| |
| @Test |
| fun collectFrom_twiceConcurrently() = testScope.runBlockingTest { |
| val differ = SimpleDiffer(dummyDifferCallback) |
| |
| val job1 = launch { |
| differ.collectFrom(infinitelySuspendingPagingData()) |
| } |
| |
| // Ensure job1 is running. |
| assertTrue { job1.isActive } |
| |
| val job2 = launch { |
| differ.collectFrom(infinitelySuspendingPagingData()) |
| } |
| |
| // job2 collection should complete job1 but not cancel. |
| assertFalse { job1.isCancelled } |
| assertTrue { job1.isCompleted } |
| job2.cancel() |
| } |
| |
| @Test |
| fun retry() = testScope.runBlockingTest { |
| val differ = SimpleDiffer(dummyDifferCallback) |
| val receiver = UiReceiverFake() |
| |
| val job = launch { |
| differ.collectFrom(infinitelySuspendingPagingData(receiver)) |
| } |
| |
| differ.retry() |
| |
| assertEquals(1, receiver.retryEvents.size) |
| |
| job.cancel() |
| } |
| |
| @Test |
| fun refresh() = testScope.runBlockingTest { |
| val differ = SimpleDiffer(dummyDifferCallback) |
| val receiver = UiReceiverFake() |
| |
| val job = launch { |
| differ.collectFrom(infinitelySuspendingPagingData(receiver)) |
| } |
| |
| differ.refresh() |
| |
| assertEquals(1, receiver.refreshEvents.size) |
| |
| job.cancel() |
| } |
| |
| @Test |
| fun listUpdateFlow() = testScope.runBlockingTest { |
| val differ = SimpleDiffer(dummyDifferCallback) |
| val pageEventFlow = flowOf<PageEvent<Int>>( |
| Refresh(listOf(), 0, 0, CombinedLoadStates.IDLE_SOURCE), |
| Prepend(listOf(), 0, CombinedLoadStates.IDLE_SOURCE), |
| Drop(PREPEND, 0, 0), |
| Refresh(listOf(TransformablePage(0, listOf(0))), 0, 0, CombinedLoadStates.IDLE_SOURCE) |
| ) |
| |
| val pagingData = PagingData(pageEventFlow, dummyReceiver) |
| |
| // Start collection for ListUpdates before collecting from differ to prevent conflation |
| // from affecting the expected events. |
| val listUpdates = mutableListOf<Boolean>() |
| val listUpdateJob = launch { |
| differ.dataRefreshFlow.collect { listUpdates.add(it) } |
| } |
| |
| val job = launch { |
| differ.collectFrom(pagingData) |
| } |
| |
| advanceUntilIdle() |
| assertThat(listUpdates).isEqualTo(listOf(true, false)) |
| |
| listUpdateJob.cancel() |
| job.cancel() |
| } |
| |
| @Test |
| fun listUpdateCallback() = testScope.runBlockingTest { |
| val differ = SimpleDiffer(dummyDifferCallback) |
| val pageEventFlow = flowOf<PageEvent<Int>>( |
| Refresh(listOf(), 0, 0, CombinedLoadStates.IDLE_SOURCE), |
| Prepend(listOf(), 0, CombinedLoadStates.IDLE_SOURCE), |
| Drop(PREPEND, 0, 0), |
| Refresh(listOf(TransformablePage(0, listOf(0))), 0, 0, CombinedLoadStates.IDLE_SOURCE) |
| ) |
| |
| val pagingData = PagingData(pageEventFlow, dummyReceiver) |
| |
| // Start listening for ListUpdates before collecting from differ to prevent conflation |
| // from affecting the expected events. |
| val listUpdates = mutableListOf<Boolean>() |
| differ.addDataRefreshListener { listUpdates.add(it) } |
| |
| val job = launch { |
| differ.collectFrom(pagingData) |
| } |
| |
| advanceUntilIdle() |
| assertThat(listUpdates).isEqualTo(listOf(true, false)) |
| |
| job.cancel() |
| } |
| |
| @Test |
| fun fetch_loadHintResentWhenUnfulfilled() = testScope.runBlockingTest { |
| val differ = SimpleDiffer(dummyDifferCallback) |
| |
| val pageEventCh = Channel<PageEvent<Int>>(Channel.UNLIMITED) |
| pageEventCh.offer( |
| Refresh( |
| pages = listOf(TransformablePage(0, listOf(0, 1))), |
| placeholdersBefore = 4, |
| placeholdersAfter = 4, |
| combinedLoadStates = CombinedLoadStates.IDLE_SOURCE |
| ) |
| ) |
| pageEventCh.offer( |
| Prepend( |
| pages = listOf(TransformablePage(-1, listOf(-1, -2))), |
| placeholdersBefore = 2, |
| combinedLoadStates = CombinedLoadStates.IDLE_SOURCE |
| ) |
| ) |
| pageEventCh.offer( |
| Append( |
| pages = listOf(TransformablePage(1, listOf(2, 3))), |
| placeholdersAfter = 2, |
| combinedLoadStates = CombinedLoadStates.IDLE_SOURCE |
| ) |
| ) |
| |
| val receiver = UiReceiverFake() |
| val job = launch { |
| differ.collectFrom( |
| // Filter the original list of 10 items to 5, removing even numbers. |
| PagingData(pageEventCh.consumeAsFlow(), receiver).filter { it % 2 != 0 } |
| ) |
| } |
| |
| assertNull(differ[0]) |
| |
| // Insert a new page, PagingDataDiffer should try to resend hint since index 0 still points |
| // to a placeholder: |
| // [null, null, [], [-1], [1], [3], null, null] |
| pageEventCh.offer( |
| Prepend( |
| pages = listOf(TransformablePage(-2, listOf())), |
| placeholdersBefore = 2, |
| combinedLoadStates = CombinedLoadStates.IDLE_SOURCE |
| ) |
| ) |
| |
| // Now index 0 has been loaded: |
| // [[-3], [], [-1], [1], [3], null, null] |
| pageEventCh.offer( |
| Prepend( |
| pages = listOf(TransformablePage(-3, listOf(-3, -4))), |
| placeholdersBefore = 0, |
| combinedLoadStates = localLoadStatesOf( |
| refreshLocal = NotLoading.Incomplete, |
| prependLocal = NotLoading.Complete, |
| appendLocal = NotLoading.Incomplete |
| ) |
| ) |
| ) |
| |
| // This index points to a valid placeholder that ends up removed by filter(). |
| assertNull(differ[5]) |
| |
| // Should only resend the hint for index 5, since index 0 has already been loaded: |
| // [[-3], [], [-1], [1], [3], [], null, null] |
| pageEventCh.offer( |
| Append( |
| pages = listOf(TransformablePage(2, listOf())), |
| placeholdersAfter = 2, |
| combinedLoadStates = localLoadStatesOf( |
| refreshLocal = NotLoading.Incomplete, |
| prependLocal = NotLoading.Complete, |
| appendLocal = NotLoading.Incomplete |
| ) |
| ) |
| ) |
| |
| // Index 5 hasn't loaded, but we are at the end of the list: |
| // [[-3], [], [-1], [1], [3], [], [5]] |
| pageEventCh.offer( |
| Append( |
| pages = listOf(TransformablePage(3, listOf(4, 5))), |
| placeholdersAfter = 0, |
| combinedLoadStates = localLoadStatesOf( |
| NotLoading.Incomplete, |
| NotLoading.Complete, |
| NotLoading.Complete |
| ) |
| |
| ) |
| ) |
| |
| assertThat(receiver.hints).isEqualTo( |
| listOf( |
| ViewportHint(-1, -2, false), |
| ViewportHint(-2, -2, false), |
| ViewportHint(1, 3, false), |
| ViewportHint(2, 1, false) |
| ) |
| ) |
| |
| job.cancel() |
| } |
| |
| @Test |
| fun fetch_loadHintResentUnlessPageDropped() = testScope.runBlockingTest { |
| val differ = SimpleDiffer(dummyDifferCallback) |
| |
| val pageEventCh = Channel<PageEvent<Int>>(Channel.UNLIMITED) |
| pageEventCh.offer( |
| Refresh( |
| pages = listOf(TransformablePage(0, listOf(0, 1))), |
| placeholdersBefore = 4, |
| placeholdersAfter = 4, |
| combinedLoadStates = CombinedLoadStates.IDLE_SOURCE |
| ) |
| ) |
| pageEventCh.offer( |
| Prepend( |
| pages = listOf(TransformablePage(-1, listOf(-1, -2))), |
| placeholdersBefore = 2, |
| combinedLoadStates = CombinedLoadStates.IDLE_SOURCE |
| ) |
| ) |
| pageEventCh.offer( |
| Append( |
| pages = listOf(TransformablePage(1, listOf(2, 3))), |
| placeholdersAfter = 2, |
| combinedLoadStates = CombinedLoadStates.IDLE_SOURCE |
| ) |
| ) |
| |
| val receiver = UiReceiverFake() |
| val job = launch { |
| differ.collectFrom( |
| // Filter the original list of 10 items to 5, removing even numbers. |
| PagingData(pageEventCh.consumeAsFlow(), receiver).filter { it % 2 != 0 } |
| ) |
| } |
| |
| assertNull(differ[0]) |
| |
| // Insert a new page, PagingDataDiffer should try to resend hint since index 0 still points |
| // to a placeholder: |
| // [null, null, [], [-1], [1], [3], null, null] |
| pageEventCh.offer( |
| Prepend( |
| pages = listOf(TransformablePage(-2, listOf())), |
| placeholdersBefore = 2, |
| combinedLoadStates = CombinedLoadStates.IDLE_SOURCE |
| ) |
| ) |
| |
| // Drop the previous page, which reset resendable index state in the PREPEND direction. |
| // [null, null, [-1], [1], [3], null, null] |
| pageEventCh.offer(Drop(loadType = PREPEND, count = 1, placeholdersRemaining = 2)) |
| |
| // Re-insert the previous page, which should not trigger resending the index due to |
| // previous page drop: |
| // [[-3], [], [-1], [1], [3], null, null] |
| pageEventCh.offer( |
| Prepend( |
| pages = listOf(TransformablePage(-2, listOf())), |
| placeholdersBefore = 2, |
| combinedLoadStates = CombinedLoadStates.IDLE_SOURCE |
| ) |
| ) |
| |
| assertThat(receiver.hints).isEqualTo( |
| listOf( |
| ViewportHint(-1, -2, false), |
| ViewportHint(-2, -2, false) |
| ) |
| ) |
| |
| job.cancel() |
| } |
| |
| @Test |
| fun peek() = testScope.runBlockingTest { |
| val differ = SimpleDiffer(dummyDifferCallback) |
| val pageEventCh = Channel<PageEvent<Int>>(Channel.UNLIMITED) |
| pageEventCh.offer( |
| Refresh( |
| pages = listOf(TransformablePage(0, listOf(0, 1))), |
| placeholdersBefore = 4, |
| placeholdersAfter = 4, |
| combinedLoadStates = CombinedLoadStates.IDLE_SOURCE |
| ) |
| ) |
| pageEventCh.offer( |
| Prepend( |
| pages = listOf(TransformablePage(-1, listOf(-1, -2))), |
| placeholdersBefore = 2, |
| combinedLoadStates = CombinedLoadStates.IDLE_SOURCE |
| ) |
| ) |
| pageEventCh.offer( |
| Append( |
| pages = listOf(TransformablePage(1, listOf(2, 3))), |
| placeholdersAfter = 2, |
| combinedLoadStates = CombinedLoadStates.IDLE_SOURCE |
| ) |
| ) |
| |
| val receiver = UiReceiverFake() |
| val job = launch { |
| differ.collectFrom( |
| // Filter the original list of 10 items to 5, removing even numbers. |
| PagingData(pageEventCh.consumeAsFlow(), receiver) |
| ) |
| } |
| |
| // Check that peek fetches the correct placeholder |
| assertThat(differ.peek(4)).isEqualTo(0) |
| |
| // Check that peek fetches the correct placeholder |
| assertNull(differ.peek(0)) |
| |
| // Check that peek does not trigger page fetch. |
| assertThat(receiver.hints).isEqualTo(listOf<ViewportHint>()) |
| |
| job.cancel() |
| } |
| } |
| |
| private fun infinitelySuspendingPagingData(receiver: UiReceiver = dummyReceiver) = |
| PagingData( |
| flow { emit(suspendCancellableCoroutine<PageEvent<Int>> { }) }, |
| receiver |
| ) |
| |
| private class UiReceiverFake : UiReceiver { |
| val hints = mutableListOf<ViewportHint>() |
| val retryEvents = mutableListOf<Unit>() |
| val refreshEvents = mutableListOf<Unit>() |
| |
| override fun addHint(hint: ViewportHint) { |
| hints.add(hint) |
| } |
| |
| override fun retry() { |
| retryEvents.add(Unit) |
| } |
| |
| override fun refresh() { |
| refreshEvents.add(Unit) |
| } |
| } |
| |
| private class SimpleDiffer(differCallback: DifferCallback) : PagingDataDiffer<Int>(differCallback) { |
| override suspend fun presentNewList( |
| previousList: NullPaddedList<Int>, |
| newList: NullPaddedList<Int>, |
| newCombinedLoadStates: CombinedLoadStates, |
| lastAccessedIndex: Int |
| ): Int? = null |
| } |
| |
| internal val dummyReceiver = object : UiReceiver { |
| override fun addHint(hint: ViewportHint) {} |
| |
| override fun retry() {} |
| |
| override fun refresh() {} |
| } |
| |
| private val dummyDifferCallback = object : DifferCallback { |
| override fun onInserted(position: Int, count: Int) {} |
| |
| override fun onChanged(position: Int, count: Int) {} |
| |
| override fun onRemoved(position: Int, count: Int) {} |
| } |