Add swipe back tests

compose/ui/ui/src/uikitInstrumentedTest/kotlin/androidx/compose/ui/interaction/swipeback/DialogSwipeBackTest.kt

@@ -0,0 +1,297 @@
+/*
+ * Copyright 2026 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.compose.ui.interaction.swipeback
+
+import androidx.compose.foundation.gestures.Orientation
+import androidx.compose.foundation.gestures.draggable
+import androidx.compose.foundation.gestures.rememberDraggableState
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableFloatStateOf
+import androidx.compose.runtime.mutableIntStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.background
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.platform.testTag
+import androidx.compose.ui.test.UIKitInstrumentedTest
+import androidx.compose.ui.test.findNodeWithTag
+import androidx.compose.ui.test.findNodeWithTagOrNull
+import androidx.compose.ui.test.runUIKitInstrumentedTest
+import androidx.compose.ui.test.utils.hold
+import androidx.compose.ui.test.utils.up
+import androidx.compose.ui.window.Dialog
+import androidx.compose.ui.window.DialogProperties
+import androidx.navigationevent.NavigationEventInfo
+import androidx.navigationevent.NavigationEventTransitionState
+import androidx.navigationevent.NavigationEventTransitionState.InProgress
+import androidx.navigationevent.compose.NavigationBackHandler
+import androidx.navigationevent.compose.rememberNavigationEventState
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertFalse
+import platform.UIKit.UITraitEnvironmentLayoutDirectionLeftToRight
+import platform.UIKit.UITraitEnvironmentLayoutDirectionRightToLeft
+
+internal class DialogSwipeBackInHostingViewTest : DialogSwipeBackTest(
+    runUIKitInstrumentedTest = { runUIKitInstrumentedTest(useHostingView = true, it) }
+)
+
+internal class DialogSwipeBackInHostingViewControllerTest : DialogSwipeBackTest(
+    runUIKitInstrumentedTest = { runUIKitInstrumentedTest(useHostingView = false, it) }
+)
+
+internal abstract class DialogSwipeBackTest(
+    private val runUIKitInstrumentedTest: (UIKitInstrumentedTest.() -> Unit) -> Unit
+) {
+    @Test
+    fun testEdgeBackSwipeOverDialogDoesNotDispatchHorizontalDragToComposeLtr() = runUIKitInstrumentedTest {
+        var dragDistance = Float.NaN
+        var transitionState: NavigationEventTransitionState = NavigationEventTransitionState.Idle
+        var backCompletedCount = -1
+
+        setContent(layoutDirection = UITraitEnvironmentLayoutDirectionLeftToRight) {
+            DialogBackGestureContent(
+                onDragDistanceChanged = { dragDistance = it },
+                onTransitionStateChanged = { transitionState = it },
+                onBackCompletedCountChanged = { backCompletedCount = it }
+            )
+        }
+
+        val backSwipe = swipeFromLeftEdge().hold()
+
+        waitForIdle()
+
+        assertFalse(
+            transitionState is InProgress,
+            "Edge swipe over Dialog should not start root back navigation"
+        )
+        assertEquals(
+            expected = 0f,
+            actual = dragDistance,
+            absoluteTolerance = 0.01f,
+            message = "Edge back swipe over Dialog should not dispatch horizontal drag deltas to Compose"
+        )
+        assertEquals(
+            expected = 0,
+            actual = backCompletedCount,
+            message = "Back gesture over Dialog should not complete before release"
+        )
+
+        backSwipe.up()
+
+        waitForIdle()
+
+        assertFalse(
+            transitionState is InProgress,
+            "Releasing edge swipe over Dialog should still not start root back navigation"
+        )
+        assertEquals(
+            expected = 0,
+            actual = backCompletedCount,
+            message = "Edge swipe over Dialog should not complete root back navigation"
+        )
+    }
+
+    @Test
+    fun testEdgeBackSwipeOverDialogDoesNotDispatchHorizontalDragToComposeRtl() = runUIKitInstrumentedTest {
+        var dragDistance = Float.NaN
+        var transitionState: NavigationEventTransitionState = NavigationEventTransitionState.Idle
+        var backCompletedCount = -1
+
+        setContent(layoutDirection = UITraitEnvironmentLayoutDirectionRightToLeft) {
+            DialogBackGestureContent(
+                onDragDistanceChanged = { dragDistance = it },
+                onTransitionStateChanged = { transitionState = it },
+                onBackCompletedCountChanged = { backCompletedCount = it }
+            )
+        }
+
+        val backSwipe = swipeFromRightEdge().hold()
+
+        waitForIdle()
+
+        assertFalse(
+            transitionState is InProgress,
+            "Edge swipe over Dialog should not start root back navigation"
+        )
+        assertEquals(
+            expected = 0f,
+            actual = dragDistance,
+            absoluteTolerance = 0.01f,
+            message = "Edge back swipe over Dialog should not dispatch horizontal drag deltas to Compose"
+        )
+        assertEquals(
+            expected = 0,
+            actual = backCompletedCount,
+            message = "Back gesture over Dialog should not complete before release"
+        )
+
+        backSwipe.up()
+
+        waitForIdle()
+
+        assertFalse(
+            transitionState is InProgress,
+            "Releasing edge swipe over Dialog should still not start root back navigation"
+        )
+        assertEquals(
+            expected = 0,
+            actual = backCompletedCount,
+            message = "Edge swipe over Dialog should not complete root back navigation"
+        )
+    }
+
+    @Test
+    fun testInnerSwipeOverDialogDispatchesHorizontalDragWithoutStartingBackLtr() = runUIKitInstrumentedTest {
+        var dragDistance = Float.NaN
+        var transitionState: NavigationEventTransitionState = NavigationEventTransitionState.Idle
+        var backCompletedCount = -1
+
+        setContent(layoutDirection = UITraitEnvironmentLayoutDirectionLeftToRight) {
+            DialogBackGestureContent(
+                onDragDistanceChanged = { dragDistance = it },
+                onTransitionStateChanged = { transitionState = it },
+                onBackCompletedCountChanged = { backCompletedCount = it }
+            )
+        }
+
+        findNodeWithTag(OVERLAY_SURFACE).swipeRight()
+
+        waitUntil("Inner swipe should dispatch drag deltas over Dialog") {
+            dragDistance > 0f
+        }
+
+        assertFalse(
+            transitionState is InProgress,
+            "Inner swipe over Dialog should not start back navigation"
+        )
+        assertEquals(
+            expected = 0,
+            actual = backCompletedCount,
+            message = "Inner swipe over Dialog should not complete back navigation"
+        )
+    }
+
+    @Test
+    fun testInnerSwipeOverDialogDispatchesHorizontalDragWithoutStartingBackRtl() = runUIKitInstrumentedTest {
+        var dragDistance = Float.NaN
+        var transitionState: NavigationEventTransitionState = NavigationEventTransitionState.Idle
+        var backCompletedCount = -1
+
+        setContent(layoutDirection = UITraitEnvironmentLayoutDirectionRightToLeft) {
+            DialogBackGestureContent(
+                onDragDistanceChanged = { dragDistance = it },
+                onTransitionStateChanged = { transitionState = it },
+                onBackCompletedCountChanged = { backCompletedCount = it }
+            )
+        }
+
+        findNodeWithTag(OVERLAY_SURFACE).swipeLeft()
+
+        waitUntil("Inner swipe should dispatch drag deltas over Dialog") {
+            dragDistance < 0f
+        }
+
+        assertFalse(
+            transitionState is InProgress,
+            "Inner swipe over Dialog should not start back navigation"
+        )
+        assertEquals(
+            expected = 0,
+            actual = backCompletedCount,
+            message = "Inner swipe over Dialog should not complete back navigation"
+        )
+    }
+}
+
+@Composable
+private fun DialogBackGestureContent(
+    onDragDistanceChanged: (Float) -> Unit,
+    onTransitionStateChanged: (NavigationEventTransitionState) -> Unit,
+    onBackCompletedCountChanged: (Int) -> Unit,
+) {
+    BackGestureHost(
+        onTransitionStateChanged = onTransitionStateChanged,
+        onBackCompletedCountChanged = onBackCompletedCountChanged
+    ) {
+        Dialog(
+            onDismissRequest = {},
+            properties = DialogProperties(
+                dismissOnBackPress = false,
+                usePlatformDefaultWidth = false,
+                usePlatformInsets = false
+            )
+        ) {
+            DraggableSurface(onDragDistanceChanged = onDragDistanceChanged)
+        }
+    }
+}
+
+@Composable
+private fun DraggableSurface(
+    onDragDistanceChanged: (Float) -> Unit,
+) {
+    var dragDistance by remember { mutableFloatStateOf(0f) }
+
+    onDragDistanceChanged(dragDistance)
+
+    Box(
+        modifier = Modifier
+            .background(Color.Red)
+            .fillMaxSize()
+            .testTag(OVERLAY_SURFACE)
+            .draggable(
+                state = rememberDraggableState { delta ->
+                    dragDistance += delta
+                },
+                orientation = Orientation.Horizontal,
+            )
+    )
+}
+
+@Composable
+private fun BackGestureHost(
+    onTransitionStateChanged: (NavigationEventTransitionState) -> Unit,
+    onBackCompletedCountChanged: (Int) -> Unit,
+    content: @Composable () -> Unit,
+) {
+    var backCompletedCount by remember { mutableIntStateOf(0) }
+    val navigationEventState = rememberNavigationEventState<NavigationEventInfo>(
+        currentInfo = NavigationEventInfo.None,
+        backInfo = listOf(NavigationEventInfo.None)
+    )
+
+    onTransitionStateChanged(navigationEventState.transitionState)
+    onBackCompletedCountChanged(backCompletedCount)
+
+    NavigationBackHandler(
+        state = navigationEventState,
+        onBackCompleted = {
+            backCompletedCount += 1
+        }
+    )
+
+    Box(modifier = Modifier.fillMaxSize()) {
+        content()
+    }
+}
+
+private const val OVERLAY_SURFACE = "overlaySurface"