Merge pull request #570 from namehillsoftware/bugfix/cancellable-aggregate-item-loading

[Bugfix] Cancellable Aggregate Item Loading

Author: davidvedvick

projectBlueWater/src/main/java/com/lasthopesoftware/bluewater/client/browsing/items/AggregateItemViewModel.kt

@@ -27,10 +27,11 @@ class AggregateItemViewModel(
 		)
 	}
 
-	override fun loadItem(libraryId: LibraryId, item: IItem?): Promise<Unit> {
+	override fun loadItem(libraryId: LibraryId, item: IItem?): Promise<Unit> = Promise.Proxy { cs ->
 		val promisedLoads = itemDataLoaders.map { it.loadItem(libraryId, item) }
 
-		return Promise.whenAll(promisedLoads)
+		Promise.whenAll(promisedLoads)
+			.also(cs::doCancel)
 			.then(
 				UnitResponse.respond(),
 				{
@@ -41,9 +42,10 @@ class AggregateItemViewModel(
 			)
 	}
 
-	override fun promiseRefresh(): Promise<Unit> {
+	override fun promiseRefresh(): Promise<Unit> = Promise.Proxy { cs ->
 		val promisedRefreshes = itemDataLoaders.map { it.promiseRefresh() }
-		return Promise.whenAll(promisedRefreshes)
+		Promise.whenAll(promisedRefreshes)
+			.also(cs::doCancel)
 			.then(
 				UnitResponse.respond(),
 				{

projectBlueWater/src/test/java/com/lasthopesoftware/bluewater/client/browsing/items/aggregate/GivenItemDataLoaders/AndLoadingIsCancelled/When Loading an Item.kt

@@ -0,0 +1,97 @@
+package com.lasthopesoftware.bluewater.client.browsing.items.aggregate.GivenItemDataLoaders.AndLoadingIsCancelled
+
+import com.lasthopesoftware.bluewater.client.browsing.items.AggregateItemViewModel
+import com.lasthopesoftware.bluewater.client.browsing.items.Item
+import com.lasthopesoftware.bluewater.client.browsing.library.repository.LibraryId
+import com.lasthopesoftware.bluewater.shared.observables.MutableInteractionState
+import com.lasthopesoftware.bluewater.shared.promises.extensions.toExpiringFuture
+import com.namehillsoftware.handoff.promises.Promise
+import io.mockk.every
+import io.mockk.mockk
+import org.assertj.core.api.Assertions.assertThat
+import org.junit.jupiter.api.BeforeAll
+import org.junit.jupiter.api.Test
+import java.util.concurrent.CancellationException
+import java.util.concurrent.ExecutionException
+
+class `When Loading an Item` {
+
+	companion object {
+		private const val libraryId = 425
+		private const val itemId = "U12rH63"
+	}
+
+	private val mut by lazy {
+		AggregateItemViewModel(
+			mockk {
+				every { loadItem(LibraryId(libraryId), Item(itemId)) } returns Promise {
+					it.awaitCancellation {
+						isFirstModelCancelled = true
+						it.sendResolution(Unit)
+					}
+				}
+
+				every { isLoading } returns MutableInteractionState(false)
+			},
+			mockk {
+				every { loadItem(LibraryId(libraryId), Item(itemId)) } returns Promise<Unit> {
+					it.awaitCancellation {
+						isSecondModelCancelled = true
+						it.sendRejection(CancellationException(":|"))
+					}
+				}
+				every { isLoading } returns MutableInteractionState(false)
+			},
+			mockk {
+				every { loadItem(LibraryId(libraryId), Item(itemId)) } returns Promise<Unit> {
+					it.awaitCancellation {
+						isThirdModelCancelled = true
+						it.sendRejection(CancellationException(":/"))
+					}
+				}
+				every { isLoading } returns MutableInteractionState(true)
+			},
+		)
+	}
+
+	private var isFirstModelCancelled = false
+	private var isSecondModelCancelled = false
+	private var isThirdModelCancelled = false
+	private var caughtException: CancellationException? = null
+
+	@BeforeAll
+	fun act() {
+		try {
+			val promisedLoadedItem = mut.loadItem(LibraryId(libraryId), Item(itemId))
+			promisedLoadedItem.cancel()
+			promisedLoadedItem.toExpiringFuture().get()
+		} catch (ee: ExecutionException) {
+			caughtException = ee.cause as? CancellationException
+		}
+	}
+
+	@Test
+	fun `then the caught exception is correct`() {
+		assertThat(caughtException).isNotNull
+	}
+
+	@Test
+	fun `then the first model is cancelled`() {
+		assertThat(isFirstModelCancelled).isTrue
+	}
+
+	@Test
+	fun `then the second model is cancelled`() {
+		assertThat(isSecondModelCancelled).isTrue
+	}
+
+	@Test
+	fun `then the third model is cancelled`() {
+		assertThat(isThirdModelCancelled).isTrue
+	}
+
+	@Test
+	fun `then the model is loading`() {
+		assertThat(mut.isLoading.value).isTrue
+	}
+}

projectBlueWater/src/test/java/com/lasthopesoftware/bluewater/client/browsing/items/aggregate/GivenItemDataLoaders/AndLoadingIsCancelled/When Refreshing an Item.kt

@@ -0,0 +1,75 @@
+package com.lasthopesoftware.bluewater.client.browsing.items.aggregate.GivenItemDataLoaders.AndLoadingIsCancelled
+
+import com.lasthopesoftware.bluewater.client.browsing.items.AggregateItemViewModel
+import com.lasthopesoftware.bluewater.shared.observables.MutableInteractionState
+import com.lasthopesoftware.bluewater.shared.promises.extensions.toExpiringFuture
+import com.namehillsoftware.handoff.promises.Promise
+import io.mockk.every
+import io.mockk.mockk
+import org.assertj.core.api.Assertions.assertThat
+import org.junit.jupiter.api.BeforeAll
+import org.junit.jupiter.api.Test
+import java.util.concurrent.CancellationException
+import java.util.concurrent.ExecutionException
+
+class `When Refreshing an Item` {
+
+	private val mut by lazy {
+		AggregateItemViewModel(
+			mockk {
+				every { promiseRefresh() } returns Promise {
+					it.awaitCancellation {
+						isFirstModelCancelled = true
+						it.sendResolution(Unit)
+					}
+				}
+
+				every { isLoading } returns MutableInteractionState(false)
+			},
+			mockk {
+				every { promiseRefresh() } returns Promise<Unit> {
+					it.awaitCancellation {
+						isSecondModelCancelled = true
+						it.sendRejection(CancellationException())
+					}
+				}
+				every { isLoading } returns MutableInteractionState(false)
+			},
+		)
+	}
+
+	private var isFirstModelCancelled = false
+	private var isSecondModelCancelled = false
+	private var caughtException: CancellationException? = null
+
+	@BeforeAll
+	fun act() {
+		try {
+			val promisedLoadedItem = mut.promiseRefresh()
+			promisedLoadedItem.cancel()
+			promisedLoadedItem.toExpiringFuture().get()
+		} catch (ee: ExecutionException) {
+			caughtException = ee.cause as? CancellationException
+		}
+	}
+
+	@Test
+	fun `then the caught exception is correct`() {
+		assertThat(caughtException).isNotNull
+	}
+
+	@Test
+	fun `then the first model is cancelled`() {
+		assertThat(isFirstModelCancelled).isTrue
+	}
+
+	@Test
+	fun `then the second model is cancelled`() {
+		assertThat(isSecondModelCancelled).isTrue
+	}
+
+	@Test
+	fun `then the model is not loading`() {
+		assertThat(mut.isLoading.value).isFalse
+	}
+}