For #24006 - Return a null change payload if the new top sites list is larger than the old

app/src/main/java/org/mozilla/fenix/home/sessioncontrol/SessionControlAdapter.kt

@@ -21,10 +21,10 @@ import org.mozilla.fenix.components.tips.Tip
 import org.mozilla.fenix.home.BottomSpacerViewHolder
 import org.mozilla.fenix.home.HomeFragmentStore
 import org.mozilla.fenix.home.TopPlaceholderViewHolder
-import org.mozilla.fenix.home.pocket.PocketStoriesViewHolder
-import org.mozilla.fenix.home.recentbookmarks.view.RecentBookmarksHeaderViewHolder
 import org.mozilla.fenix.home.pocket.PocketCategoriesViewHolder
 import org.mozilla.fenix.home.pocket.PocketRecommendationsHeaderViewHolder
+import org.mozilla.fenix.home.pocket.PocketStoriesViewHolder
+import org.mozilla.fenix.home.recentbookmarks.view.RecentBookmarksHeaderViewHolder
 import org.mozilla.fenix.home.recentbookmarks.view.RecentBookmarksViewHolder
 import org.mozilla.fenix.home.recenttabs.view.RecentTabViewHolder
 import org.mozilla.fenix.home.recenttabs.view.RecentTabsHeaderViewHolder
@@ -84,11 +84,13 @@ sealed class AdapterItem(@LayoutRes val viewType: Int) {
          *
          * See https://github.com/mozilla-mobile/fenix/pull/20189#issuecomment-877124730
          */
+        @Suppress("ComplexCondition")
         override fun getChangePayload(newItem: AdapterItem): Any? {
             val newTopSites = (newItem as? TopSitePager)
             val oldTopSites = (this as? TopSitePager)
 
             if (newTopSites == null || oldTopSites == null ||
+                newTopSites.topSites.size > oldTopSites.topSites.size ||
                 (newTopSites.topSites.size > TopSitePagerViewHolder.TOP_SITES_PER_PAGE)
                 != (oldTopSites.topSites.size > TopSitePagerViewHolder.TOP_SITES_PER_PAGE)
             ) {

app/src/test/java/org/mozilla/fenix/home/sessioncontrol/SessionControlAdapterTest.kt

@@ -49,6 +49,18 @@ class SessionControlAdapterTest {
         assertNull(result)
     }
 
+    @Test
+    fun `GIVEN topSitePager with 3 topSites WHEN getChangePayload with 5 items THEN return null`() {
+        val newItem = TopSitePager(mockk(relaxed = true))
+        val topSitePager = TopSitePager(mockk(relaxed = true))
+        every { topSitePager.topSites.size } returns 3
+        every { newItem.topSites.size } returns 5
+
+        val result = topSitePager.getChangePayload(newItem)
+
+        assertNull(result)
+    }
+
     @Test
     fun `GIVEN two topSites WHEN getChangePayload called with one changed item THEN return TopSitePagerPayload with changes`() {
         val topSite0 = TopSite.Frecent(-1, "topSite0", "", 0)