test: cover delete flows and guard re-entrant mutations

app/src/main/java/space/hackenslacker/kanbn4droid/app/boarddetail/BoardDetailViewModel.kt

@@ -153,6 +153,9 @@ class BoardDetailViewModel(
 
     fun submitRenameList() {
         val snapshot = _uiState.value
+        if (snapshot.isMutating) {
+            return
+        }
         val editingListId = snapshot.editingListId ?: return
         val currentList = snapshot.boardDetail?.lists?.firstOrNull { it.id == editingListId } ?: return
         val trimmedTitle = snapshot.editingListTitle.trim()
@@ -238,6 +241,9 @@ class BoardDetailViewModel(
         mutation: suspend (Set<String>) -> CardBatchMutationResult,
     ) {
         val preMutation = _uiState.value
+        if (preMutation.isMutating) {
+            return
+        }
         val selectedIds = preMutation.selectedCardIds
         if (selectedIds.isEmpty()) {
             return

app/src/test/java/space/hackenslacker/kanbn4droid/app/boarddetail/BoardDetailViewModelTest.kt

@@ -1,6 +1,7 @@
 package space.hackenslacker.kanbn4droid.app.boarddetail
 
 import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.CompletableDeferred
 import kotlinx.coroutines.async
 import kotlinx.coroutines.flow.first
 import kotlinx.coroutines.test.StandardTestDispatcher
@@ -304,6 +305,99 @@ class BoardDetailViewModelTest {
         assertEquals("Cannot move", (event as BoardDetailUiEvent.ShowServerError).message)
     }
 
+    @Test
+    fun deleteSuccessWithReloadSuccessClearsSelection() = runTest {
+        val repository = FakeBoardDetailDataSource(
+            boardDetailResults = ArrayDeque(
+                listOf(
+                    BoardsApiResult.Success(detailWithTwoLists()),
+                    BoardsApiResult.Success(detailWithTwoLists()),
+                ),
+            ),
+            deleteCardsResult = CardBatchMutationResult.Success,
+        )
+        val viewModel = newLoadedViewModel(this, repository)
+        viewModel.onCardLongPressed("card-1")
+
+        viewModel.deleteSelectedCards()
+        advanceUntilIdle()
+
+        assertTrue(viewModel.uiState.value.selectedCardIds.isEmpty())
+    }
+
+    @Test
+    fun deletePartialWithReloadSuccessReselectsFailedIdsStillVisibleAndWarns() = runTest {
+        val repository = FakeBoardDetailDataSource(
+            boardDetailResults = ArrayDeque(
+                listOf(
+                    BoardsApiResult.Success(detailWithTwoLists()),
+                    BoardsApiResult.Success(detailOnlyCardThree()),
+                ),
+            ),
+            deleteCardsResult = CardBatchMutationResult.PartialSuccess(
+                failedCardIds = setOf("card-2", "card-3"),
+                message = "Some cards could not be deleted.",
+            ),
+        )
+        val viewModel = newLoadedViewModel(this, repository)
+        viewModel.onCardLongPressed("card-1")
+        viewModel.onCardLongPressed("card-2")
+        viewModel.onCardLongPressed("card-3")
+        val eventDeferred = async { viewModel.events.first() }
+
+        viewModel.deleteSelectedCards()
+        advanceUntilIdle()
+
+        assertEquals(setOf("card-3"), viewModel.uiState.value.selectedCardIds)
+        val event = eventDeferred.await()
+        assertTrue(event is BoardDetailUiEvent.ShowWarning)
+        assertEquals("Some cards could not be deleted.", (event as BoardDetailUiEvent.ShowWarning).message)
+    }
+
+    @Test
+    fun deleteFailurePreservesSelectionAndEmitsServerError() = runTest {
+        val repository = FakeBoardDetailDataSource(
+            boardDetailResults = ArrayDeque(listOf(BoardsApiResult.Success(detailWithTwoLists()))),
+            deleteCardsResult = CardBatchMutationResult.Failure("Delete blocked"),
+        )
+        val viewModel = newLoadedViewModel(this, repository)
+        viewModel.onCardLongPressed("card-1")
+        val eventDeferred = async { viewModel.events.first() }
+
+        viewModel.deleteSelectedCards()
+        advanceUntilIdle()
+
+        assertEquals(setOf("card-1"), viewModel.uiState.value.selectedCardIds)
+        val event = eventDeferred.await()
+        assertTrue(event is BoardDetailUiEvent.ShowServerError)
+        assertEquals("Delete blocked", (event as BoardDetailUiEvent.ShowServerError).message)
+    }
+
+    @Test
+    fun runMutationNoOpsWhenAlreadyMutating() = runTest {
+        val gate = CompletableDeferred<Unit>()
+        val repository = FakeBoardDetailDataSource(
+            boardDetailResults = ArrayDeque(
+                listOf(
+                    BoardsApiResult.Success(detailWithTwoLists()),
+                    BoardsApiResult.Success(detailWithTwoLists()),
+                ),
+            ),
+            moveCardsResult = CardBatchMutationResult.Success,
+            moveGate = gate,
+        )
+        val viewModel = newLoadedViewModel(this, repository)
+        viewModel.onCardLongPressed("card-1")
+
+        viewModel.moveSelectedCards("list-2")
+        advanceUntilIdle()
+        viewModel.moveSelectedCards("list-2")
+        gate.complete(Unit)
+        advanceUntilIdle()
+
+        assertEquals(1, repository.moveCalls)
+    }
+
     @Test
     fun renameNoOpSkipsApiCallAndExitsEditMode() = runTest {
         val repository = FakeBoardDetailDataSource(
@@ -369,6 +463,32 @@ class BoardDetailViewModelTest {
         assertEquals("Rename rejected", (event as BoardDetailUiEvent.ShowServerError).message)
     }
 
+    @Test
+    fun submitRenameNoOpsWhenAlreadyMutating() = runTest {
+        val gate = CompletableDeferred<Unit>()
+        val repository = FakeBoardDetailDataSource(
+            boardDetailResults = ArrayDeque(
+                listOf(
+                    BoardsApiResult.Success(detailWithSingleList()),
+                    BoardsApiResult.Success(detailWithSingleList()),
+                ),
+            ),
+            renameListResult = BoardsApiResult.Success(Unit),
+            renameGate = gate,
+        )
+        val viewModel = newLoadedViewModel(this, repository)
+
+        viewModel.startEditingList("list-1")
+        viewModel.updateEditingTitle("Renamed")
+        viewModel.submitRenameList()
+        advanceUntilIdle()
+        viewModel.submitRenameList()
+        gate.complete(Unit)
+        advanceUntilIdle()
+
+        assertEquals(1, repository.renameCalls)
+    }
+
     private fun newLoadedViewModel(
         scope: TestScope,
         repository: FakeBoardDetailDataSource,
@@ -389,7 +509,11 @@ class BoardDetailViewModelTest {
         var moveCardsResult: CardBatchMutationResult = CardBatchMutationResult.Success,
         var deleteCardsResult: CardBatchMutationResult = CardBatchMutationResult.Success,
         var renameListResult: BoardsApiResult<Unit> = BoardsApiResult.Success(Unit),
+        var moveGate: CompletableDeferred<Unit>? = null,
+        var renameGate: CompletableDeferred<Unit>? = null,
     ) : BoardDetailDataSource {
+        var moveCalls: Int = 0
+        var deleteCalls: Int = 0
         var renameCalls: Int = 0
         var lastRenameListId: String? = null
         var lastRenameTitle: String? = null
@@ -403,15 +527,19 @@ class BoardDetailViewModelTest {
         }
 
         override suspend fun moveCards(cardIds: Collection<String>, targetListId: String): CardBatchMutationResult {
+            moveCalls += 1
+            moveGate?.await()
             return moveCardsResult
         }
 
         override suspend fun deleteCards(cardIds: Collection<String>): CardBatchMutationResult {
+            deleteCalls += 1
             return deleteCardsResult
         }
 
         override suspend fun renameList(listId: String, newTitle: String): BoardsApiResult<Unit> {
             renameCalls += 1
+            renameGate?.await()
             lastRenameListId = listId
             lastRenameTitle = newTitle
             return renameListResult