From db644bfe8f87965231daf1fe50d739f881c10a57 Mon Sep 17 00:00:00 2001
From: Chris Banes <chris@banes.me>
Date: Tue, 27 Apr 2021 10:01:08 +0100
Subject: [PATCH] [Pager] Re-enable animateScrollToPage() test

---
 .../accompanist/pager/HorizontalPagerTest.kt  |  3 +++
 .../com/google/accompanist/pager/PagerTest.kt | 19 ++++++++++++++++---
 .../accompanist/pager/VerticalPagerTest.kt    |  3 +++
 3 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/pager/src/androidTest/java/com/google/accompanist/pager/HorizontalPagerTest.kt b/pager/src/androidTest/java/com/google/accompanist/pager/HorizontalPagerTest.kt
index a229fd224..fcf5fc4ac 100644
--- a/pager/src/androidTest/java/com/google/accompanist/pager/HorizontalPagerTest.kt
+++ b/pager/src/androidTest/java/com/google/accompanist/pager/HorizontalPagerTest.kt
@@ -22,6 +22,7 @@ import androidx.compose.foundation.layout.aspectRatio
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.text.BasicText
+import androidx.compose.runtime.rememberCoroutineScope
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.platform.testTag
@@ -159,6 +160,8 @@ class HorizontalPagerTest(
     ): PagerState {
         val pagerState = PagerState(pageCount = pageCount)
         composeTestRule.setContent(layoutDirection) {
+            applierScope = rememberCoroutineScope()
+
             HorizontalPager(
                 state = pagerState,
                 itemSpacing = itemSpacingDp.dp,
diff --git a/pager/src/androidTest/java/com/google/accompanist/pager/PagerTest.kt b/pager/src/androidTest/java/com/google/accompanist/pager/PagerTest.kt
index 25180cc43..a2658b294 100644
--- a/pager/src/androidTest/java/com/google/accompanist/pager/PagerTest.kt
+++ b/pager/src/androidTest/java/com/google/accompanist/pager/PagerTest.kt
@@ -25,9 +25,11 @@ import androidx.compose.ui.test.onNodeWithTag
 import androidx.compose.ui.test.onParent
 import androidx.compose.ui.test.performScrollTo
 import com.google.common.truth.Truth.assertThat
+import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.ExperimentalCoroutinesApi
 import kotlinx.coroutines.FlowPreview
 import kotlinx.coroutines.flow.produceIn
+import kotlinx.coroutines.withContext
 import org.junit.Ignore
 import org.junit.Rule
 import org.junit.Test
@@ -49,6 +51,12 @@ abstract class PagerTest {
     @get:Rule
     val composeTestRule = createComposeRule()
 
+    /**
+     * This is a workaround for https://issuetracker.google.com/issues/179492185.
+     * Ideally we would have a way to get the applier scope from the rule
+     */
+    protected lateinit var applierScope: CoroutineScope
+
     @Test
     fun layout() {
         setPagerContent(pageCount = 10)
@@ -196,15 +204,20 @@ abstract class PagerTest {
 
     @OptIn(ExperimentalCoroutinesApi::class)
     @Test
-    @Ignore("https://issuetracker.google.com/185228750")
     fun animateScrollToPage() = suspendTest {
         val pagerState = setPagerContent(pageCount = 10)
 
-        pagerState.animateScrollToPage(3)
+        withContext(applierScope.coroutineContext) {
+            pagerState.animateScrollToPage(3)
+        }
+        composeTestRule.awaitIdle()
         assertThat(pagerState.currentPage).isEqualTo(3)
         assertPagerLayout(3)
 
-        pagerState.animateScrollToPage(0)
+        withContext(applierScope.coroutineContext) {
+            pagerState.animateScrollToPage(0)
+        }
+        composeTestRule.awaitIdle()
         assertThat(pagerState.currentPage).isEqualTo(0)
         assertPagerLayout(0)
     }
diff --git a/pager/src/androidTest/java/com/google/accompanist/pager/VerticalPagerTest.kt b/pager/src/androidTest/java/com/google/accompanist/pager/VerticalPagerTest.kt
index 8576139af..383d30c32 100644
--- a/pager/src/androidTest/java/com/google/accompanist/pager/VerticalPagerTest.kt
+++ b/pager/src/androidTest/java/com/google/accompanist/pager/VerticalPagerTest.kt
@@ -22,6 +22,7 @@ import androidx.compose.foundation.layout.aspectRatio
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.text.BasicText
+import androidx.compose.runtime.rememberCoroutineScope
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.platform.testTag
@@ -122,6 +123,8 @@ class VerticalPagerTest(
         val pagerState = PagerState(pageCount = pageCount)
         // Stick to LTR for vertical tests
         composeTestRule.setContent(LayoutDirection.Ltr) {
+            applierScope = rememberCoroutineScope()
+
             VerticalPager(
                 state = pagerState,
                 offscreenLimit = offscreenLimit,