📰 Stop refreshing the whole NTP for every adapter change

chrome/android/junit/src/org/chromium/chrome/browser/ntp/cards/NewTabPageAdapterTest.java

Index: chrome/android/junit/src/org/chromium/chrome/browser/ntp/cards/NewTabPageAdapterTest.java
diff --git a/chrome/android/junit/src/org/chromium/chrome/browser/ntp/cards/NewTabPageAdapterTest.java b/chrome/android/junit/src/org/chromium/chrome/browser/ntp/cards/NewTabPageAdapterTest.java
index 1cc00284d7e5e508c1212f520d9ab3f462dec659..d427cdc85f48c70db06b232f71a22fb758381130 100644
--- a/chrome/android/junit/src/org/chromium/chrome/browser/ntp/cards/NewTabPageAdapterTest.java
+++ b/chrome/android/junit/src/org/chromium/chrome/browser/ntp/cards/NewTabPageAdapterTest.java
@@ -4,12 +4,17 @@
 
 package org.chromium.chrome.browser.ntp.cards;
 
+import static org.chromium.chrome.browser.ntp.cards.ContentSuggestionsTestUtils.createDummySuggestions;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
+import static org.mockito.Mockito.any;
+import static org.mockito.Mockito.anyString;
+import static org.mockito.Mockito.doNothing;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
 
 import android.support.annotation.Nullable;
 import android.view.ContextMenu;
@@ -214,6 +219,7 @@ public void setUp() {
                 new SuggestionsCategoryInfo("Articles for you",
                                            ContentSuggestionsCardLayout.FULL_CARD, false, true));
         mAdapter = new NewTabPageAdapter(new MockNewTabPageManager(mSource), null, null);
+        mAdapter.initializeSections();
     }
 
     /**
@@ -397,20 +403,20 @@ public void testSectionClearingWhenUnavailable() {
         assertItemsFor();
 
         // Same when loading a new NTP.
-        mAdapter = new NewTabPageAdapter(new MockNewTabPageManager(mSource), null, null);
+        mAdapter.initializeSections();
         assertItemsFor();
 
         // Same for CATEGORY_EXPLICITLY_DISABLED.
         mSource.setStatusForCategory(KnownCategories.ARTICLES, CategoryStatus.AVAILABLE);
         mSource.setSuggestionsForCategory(KnownCategories.ARTICLES, snippets);
-        mAdapter = new NewTabPageAdapter(new MockNewTabPageManager(mSource), null, null);
+        mAdapter.initializeSections();
         assertItemsFor(section(5));
         mSource.setStatusForCategory(
                 KnownCategories.ARTICLES, CategoryStatus.CATEGORY_EXPLICITLY_DISABLED);
         assertItemsFor();
 
         // Same when loading a new NTP.
-        mAdapter = new NewTabPageAdapter(new MockNewTabPageManager(mSource), null, null);
+        mAdapter.initializeSections();
         assertItemsFor();
     }
 
@@ -431,7 +437,7 @@ public void testUIUntouchedWhenNotProvided() {
         assertItemsFor(section(4));
 
         // But it disappears when loading a new NTP.
-        mAdapter = new NewTabPageAdapter(new MockNewTabPageManager(mSource), null, null);
+        mAdapter.initializeSections();
         assertItemsFor();
     }
 
@@ -443,6 +449,7 @@ public void testSectionVisibleIfEmpty() {
         final List<SnippetArticle> articles =
                 Collections.unmodifiableList(createDummySuggestions(3));
         FakeSuggestionsSource suggestionsSource;
+        MockNewTabPageManager newTabPageManager;
 
         // Part 1: VisibleIfEmpty = true
         suggestionsSource = new FakeSuggestionsSource();
@@ -450,9 +457,11 @@ public void testSectionVisibleIfEmpty() {
         suggestionsSource.setInfoForCategory(
                 category, new SuggestionsCategoryInfo(
                                   "", ContentSuggestionsCardLayout.MINIMAL_CARD, false, true));
+        newTabPageManager = new MockNewTabPageManager(suggestionsSource);
+        mAdapter = new NewTabPageAdapter(newTabPageManager, null, null);
 
         // 1.1 - Initial state
-        mAdapter = new NewTabPageAdapter(new MockNewTabPageManager(suggestionsSource), null, null);
+        mAdapter.initializeSections();
         assertItemsFor(sectionWithStatusCard());
 
         // 1.2 - With suggestions
@@ -477,7 +486,8 @@ public void testSectionVisibleIfEmpty() {
                                   "", ContentSuggestionsCardLayout.MINIMAL_CARD, false, false));
 
         // 2.1 - Initial state
-        mAdapter = new NewTabPageAdapter(new MockNewTabPageManager(suggestionsSource), null, null);
+        newTabPageManager.setSuggestionsSource(suggestionsSource);
+        mAdapter.initializeSections();
         assertItemsFor();
 
         // 2.2 - With suggestions
@@ -500,6 +510,7 @@ public void testMoreButton() {
                 Collections.unmodifiableList(createDummySuggestions(3));
         FakeSuggestionsSource suggestionsSource;
         SuggestionsSection section42;
+        MockNewTabPageManager newTabPageManager;
 
         // Part 1: ShowMoreButton = true
         suggestionsSource = new FakeSuggestionsSource();
@@ -507,9 +518,12 @@ public void testMoreButton() {
         suggestionsSource.setInfoForCategory(
                 category, new SuggestionsCategoryInfo(
                                   "", ContentSuggestionsCardLayout.MINIMAL_CARD, true, true));
+        newTabPageManager = new MockNewTabPageManager(suggestionsSource);
+        mAdapter = new NewTabPageAdapter(newTabPageManager, null, null);
 
         // 1.1 - Initial state.
-        mAdapter = new NewTabPageAdapter(new MockNewTabPageManager(suggestionsSource), null, null);
+        newTabPageManager.setSuggestionsSource(suggestionsSource);
+        mAdapter.initializeSections();
         assertItemsFor(sectionWithStatusCardAndMoreButton());
 
         // 1.2 - With suggestions.
@@ -534,7 +548,8 @@ public void testMoreButton() {
                                   "", ContentSuggestionsCardLayout.MINIMAL_CARD, false, true));
 
         // 2.1 - Initial state.
-        mAdapter = new NewTabPageAdapter(new MockNewTabPageManager(suggestionsSource), null, null);
+        newTabPageManager.setSuggestionsSource(suggestionsSource);
+        mAdapter.initializeSections();
         assertItemsFor(sectionWithStatusCard());
 
         // 2.2 - With suggestions.
@@ -587,7 +602,7 @@ public void testDynamicCategories() {
                                           ContentSuggestionsCardLayout.MINIMAL_CARD, true, false));
         mSource.setStatusForCategory(dynamicCategory1, CategoryStatus.AVAILABLE);
         mSource.setSuggestionsForCategory(dynamicCategory1, dynamics1);
-        mAdapter = new NewTabPageAdapter(new MockNewTabPageManager(mSource), null, null); // Reload
+        mAdapter.initializeSections(); // Reload
         assertItemsFor(section(3), sectionWithMoreButton(5));
 
         int dynamicCategory2 = 1011;
@@ -597,7 +612,7 @@ public void testDynamicCategories() {
                                           ContentSuggestionsCardLayout.MINIMAL_CARD, false, false));
         mSource.setStatusForCategory(dynamicCategory2, CategoryStatus.AVAILABLE);
         mSource.setSuggestionsForCategory(dynamicCategory2, dynamics2);
-        mAdapter = new NewTabPageAdapter(new MockNewTabPageManager(mSource), null, null); // Reload
+        mAdapter.initializeSections(); // Reload
         assertItemsFor(section(3), sectionWithMoreButton(5), section(11));
     }
 
@@ -612,9 +627,10 @@ public void testCategoryOrder() {
         registerCategory(suggestionsSource, KnownCategories.BOOKMARKS, 0);
         registerCategory(suggestionsSource, KnownCategories.PHYSICAL_WEB_PAGES, 0);
         registerCategory(suggestionsSource, KnownCategories.DOWNLOADS, 0);
+        MockNewTabPageManager newTabPageManager = new MockNewTabPageManager(suggestionsSource);
 
-        NewTabPageAdapter ntpAdapter = new NewTabPageAdapter(
-                new MockNewTabPageManager(suggestionsSource), null, null);
+        NewTabPageAdapter ntpAdapter = new NewTabPageAdapter(newTabPageManager, null, null);
+        ntpAdapter.initializeSections();
         List<ItemGroup> groups = ntpAdapter.getGroups();
 
         assertEquals(7, groups.size());
@@ -635,8 +651,8 @@ public void testCategoryOrder() {
         registerCategory(suggestionsSource, KnownCategories.DOWNLOADS, 0);
         registerCategory(suggestionsSource, KnownCategories.BOOKMARKS, 0);
 
-        ntpAdapter = new NewTabPageAdapter(
-                new MockNewTabPageManager(suggestionsSource), null, null);
+        newTabPageManager.setSuggestionsSource(suggestionsSource);
+        ntpAdapter.initializeSections();
         groups = ntpAdapter.getGroups();
 
         assertEquals(7, groups.size());
@@ -656,8 +672,8 @@ public void testCategoryOrder() {
         registerCategory(suggestionsSource, KnownCategories.PHYSICAL_WEB_PAGES, 0);
         registerCategory(suggestionsSource, KnownCategories.DOWNLOADS, 0);
 
-        ntpAdapter = new NewTabPageAdapter(
-                new MockNewTabPageManager(suggestionsSource), null, null);
+        newTabPageManager.setSuggestionsSource(suggestionsSource);
+        ntpAdapter.initializeSections();
 
         // The adapter is already initialised, it will not accept new categories anymore.
         registerCategory(suggestionsSource, 42, 1);
@@ -677,53 +693,67 @@ public void testCategoryOrder() {
 
     @Test
     @Feature({"Ntp"})
-    public void testDismissSibling() {
-        List<SnippetArticle> snippets = createDummySuggestions(3);
-        SuggestionsSection section;
-
-        // Part 1: ShowMoreButton = true
-        section = new SuggestionsSection(42,
-                new SuggestionsCategoryInfo("", ContentSuggestionsCardLayout.FULL_CARD, true, true),
-                null);
-        section.setStatus(CategoryStatus.AVAILABLE);
-        assertNotNull(section.getActionItem());
-
-        // 1.1: Without snippets
-        assertEquals(-1, section.getDismissSiblingPosDelta(section.getActionItem()));
-        assertEquals(1, section.getDismissSiblingPosDelta(section.getStatusItem()));
-
-        // 1.2: With snippets
-        section.setSuggestions(snippets, CategoryStatus.AVAILABLE);
-        assertEquals(0, section.getDismissSiblingPosDelta(section.getActionItem()));
-        assertEquals(0, section.getDismissSiblingPosDelta(section.getStatusItem()));
-        assertEquals(0, section.getDismissSiblingPosDelta(snippets.get(0)));
-
-        // Part 2: ShowMoreButton = false
-        section = new SuggestionsSection(42,
-                new SuggestionsCategoryInfo("", ContentSuggestionsCardLayout.FULL_CARD, false,
-                                                 true),
-                null);
-        section.setStatus(CategoryStatus.AVAILABLE);
-        assertNull(section.getActionItem());
-
-        // 2.1: Without snippets
-        assertEquals(0, section.getDismissSiblingPosDelta(section.getStatusItem()));
-
-        // 2.2: With snippets
-        section.setSuggestions(snippets, CategoryStatus.AVAILABLE);
-        assertEquals(0, section.getDismissSiblingPosDelta(section.getStatusItem()));
-        assertEquals(0, section.getDismissSiblingPosDelta(snippets.get(0)));
-    }
-
-    private List<SnippetArticle> createDummySuggestions(int count) {
-        List<SnippetArticle> suggestions = new ArrayList<>();
-        for (int index = 0; index < count; index++) {
-            suggestions.add(new SnippetArticle(0, "https://site.com/url" + index, "title" + index,
-                    "pub" + index, "txt" + index, "https://site.com/url" + index,
-                    "https://amp.site.com/url" + index, 0, 0, 0,
-                    ContentSuggestionsCardLayout.FULL_CARD));
-        }
-        return suggestions;
+    public void testChangeNotifications() {
+        FakeSuggestionsSource suggestionsSource = spy(new FakeSuggestionsSource());
+        // Allow using dismissSuggestion() instead of throwing UnsupportedOperationException.
+        doNothing().when(suggestionsSource).dismissSuggestion(any(SnippetArticle.class));
+
+        registerCategory(suggestionsSource, KnownCategories.ARTICLES, 3);
+        NewTabPageAdapter adapter = spy(
+                new NewTabPageAdapter(new MockNewTabPageManager(suggestionsSource), null, null));
+        adapter.initializeSections();
+        doNothing().when(adapter).announceItemRemoved(anyString());
+
+        // Adapter content:
+        // Idx | Item
+        // ----|----------------
+        // 0   | Above-the-fold
+        // 1   | Header
+        // 2-4 | Sugg*3
+        // 5   | Footer
+        // 6   | Spacer
+
+        adapter.dismissItem(3); // Dismiss the second suggestion of the second section.
+        verify(adapter).notifyItemRemoved(3);
+
+        // Make sure the call with the updated position works properly.
+        adapter.dismissItem(3);
+        verify(adapter, times(2)).notifyItemRemoved(3);
+
+        // Dismiss the last suggestion in the section. We should now show the status card.
+        adapter.dismissItem(2);
+        verify(adapter).notifyItemRangeChanged(1, 2);
+        verify(adapter).notifyItemRangeInserted(3, 1);
+
+        // Adapter content:
+        // Idx | Item
+        // ----|----------------
+        // 0   | Above-the-fold
+        // 1   | Header
+        // 2   | Status
+        // 3   | Progress Indicator
+        // 4   | Footer
+        // 5   | Spacer
+
+        final int newSuggestionCount = 7;
+        suggestionsSource.setSuggestionsForCategory(
+                KnownCategories.ARTICLES, createDummySuggestions(newSuggestionCount));
+        adapter.onNewSuggestions(KnownCategories.ARTICLES);
+        verify(adapter).notifyItemRangeChanged(1, 3); // Header stays, 2 items replaced by articles.
+        verify(adapter).notifyItemRangeInserted(4, newSuggestionCount - 2);
+
+        // Adapter content:
+        // Idx | Item
+        // ----|----------------
+        // 0   | Above-the-fold
+        // 1   | Header
+        // 2-8 | Sugg*7
+        // 9   | Footer
+        // 10  | Spacer
+
+        adapter.onCategoryStatusChanged(KnownCategories.ARTICLES, CategoryStatus.SIGNED_OUT);
+        verify(adapter, times(2)).notifyItemRangeChanged(1, 3);
+        verify(adapter).notifyItemRangeRemoved(4, newSuggestionCount - 2);
     }
 
     /** Registers the category with hasMoreButton=false and showIfEmpty=true*/
@@ -900,5 +930,9 @@ public void onLearnMoreClicked() {
         @Nullable public SuggestionsSource getSuggestionsSource() {
             return mSuggestionsSource;
         }
+
+        public void setSuggestionsSource(SuggestionsSource suggestionsSource) {
+            mSuggestionsSource = suggestionsSource;
+        }
     }
 }