[fenix] For https://github.com/mozilla-mobile/fenix/issues/16461 - Ensure the proper items order after exiting Multiselect (https://github.com/mozilla-mobile/fenix/pull/16482)

app/src/main/java/org/mozilla/fenix/tabtray/SyncedTabsController.kt

@@ -21,6 +21,7 @@ import mozilla.components.browser.storage.sync.SyncedDeviceTabs
 import mozilla.components.feature.syncedtabs.view.SyncedTabsView
 import mozilla.components.lib.state.ext.flowScoped
 import mozilla.components.support.ktx.kotlinx.coroutines.flow.ifChanged
+import org.mozilla.fenix.ext.settings
 import org.mozilla.fenix.sync.ListenerDelegate
 import org.mozilla.fenix.sync.SyncedTabsAdapter
 import org.mozilla.fenix.sync.ext.toAdapterList
@@ -50,7 +51,11 @@ class SyncedTabsController(
                 .collect { mode ->
                     when (mode) {
                         is TabTrayDialogFragmentState.Mode.Normal -> {
-                            concatAdapter.addAdapter(0, adapter)
+                            if (view.context.settings().gridTabView) {
+                                concatAdapter.addAdapter(adapter)
+                            } else {
+                                concatAdapter.addAdapter(0, adapter)
+                            }
                         }
                         is TabTrayDialogFragmentState.Mode.MultiSelect -> {
                             concatAdapter.removeAdapter(adapter)

app/src/test/java/org/mozilla/fenix/tabtray/SyncedTabsControllerTest.kt

@@ -25,6 +25,7 @@ import org.junit.Rule
 import org.junit.Test
 import org.junit.runner.RunWith
 import org.mozilla.fenix.R
+import org.mozilla.fenix.ext.settings
 import org.mozilla.fenix.helpers.FenixRobolectricTestRunner
 import org.mozilla.fenix.sync.SyncedTabsViewHolder
 import org.mozilla.fenix.tabtray.TabTrayDialogFragmentAction.EnterMultiSelectMode
@@ -54,6 +55,7 @@ class SyncedTabsControllerTest {
         every { lifecycleOwner.lifecycle } returns lifecycle
 
         concatAdapter = mockk()
+        every { concatAdapter.addAdapter(any()) } returns true
         every { concatAdapter.addAdapter(any(), any()) } returns true
         every { concatAdapter.removeAdapter(any()) } returns true
 
@@ -128,12 +130,22 @@ class SyncedTabsControllerTest {
 
     @Test
     fun `concatAdapter updated on mode changes`() = testDispatcher.runBlockingTest {
-        store.dispatch(EnterMultiSelectMode).joinBlocking()
+        // When returning from Multiselect while in grid view the adapter should be added at the end
+        every { view.context.settings().gridTabView } returns true
 
+        store.dispatch(EnterMultiSelectMode).joinBlocking()
         verify { concatAdapter.removeAdapter(any()) }
 
         store.dispatch(ExitMultiSelectMode).joinBlocking()
+        verify { concatAdapter.addAdapter(any()) }
 
+        // When returning from Multiselect while in list view the adapter should be added at the front
+        every { view.context.settings().gridTabView } returns false
+
+        store.dispatch(EnterMultiSelectMode).joinBlocking()
+        verify { concatAdapter.removeAdapter(any()) }
+
+        store.dispatch(ExitMultiSelectMode).joinBlocking()
         verify { concatAdapter.addAdapter(0, any()) }
     }
 }