Wait in ReorderWidgets test for the workapce to load after changing it.

Fix: 252860608
Test: atest ReorderWidgets
Change-Id: Idf99188837a475d0327174e264ab1d23d646d75d
diff --git a/tests/src/com/android/launcher3/celllayout/ReorderWidgets.java b/tests/src/com/android/launcher3/celllayout/ReorderWidgets.java
index 2846cae..9ba3f7b 100644
--- a/tests/src/com/android/launcher3/celllayout/ReorderWidgets.java
+++ b/tests/src/com/android/launcher3/celllayout/ReorderWidgets.java
@@ -116,7 +116,7 @@
         FavoriteItemsTransaction transaction =
                 new FavoriteItemsTransaction(mTargetContext, this);
         mWorkspaceBuilder.buildFromBoard(testCase.mStart, transaction).commit();
-
+        waitForLauncherCondition("Workspace didn't finish loading", l -> !l.isWorkspaceLoading());
         Widget widget = mLauncher.getWorkspace().getWidgetAtCell(mainWidgetCellPos.x,
                 mainWidgetCellPos.y);
         assertNotNull(widget);