Implement single-selection mode for SelectionDelegate.

chrome/android/junit/src/org/chromium/chrome/browser/widget/selection/SelectionDelegateTest.java

Index: chrome/android/junit/src/org/chromium/chrome/browser/widget/selection/SelectionDelegateTest.java
diff --git a/chrome/android/junit/src/org/chromium/chrome/browser/widget/selection/SelectionDelegateTest.java b/chrome/android/junit/src/org/chromium/chrome/browser/widget/selection/SelectionDelegateTest.java
new file mode 100644
index 0000000000000000000000000000000000000000..9e2c04bfd153ddc880a630ec56f82e1e5f83e851
--- /dev/null
+++ b/chrome/android/junit/src/org/chromium/chrome/browser/widget/selection/SelectionDelegateTest.java
@@ -0,0 +1,117 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.

[Michael van Ouwerkerk, 2017/04/04 13:54:31]

nit: 2017

[Finnur, 2017/04/04 16:13:36]

Done.

+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.chrome.browser.widget.selection;
+
+import static org.junit.Assert.assertEquals;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.robolectric.annotation.Config;
+
+import org.chromium.testing.local.LocalRobolectricTestRunner;
+
+import java.util.List;
+
+/**
+ * Tests for the SelectionDelegate class.

[Michael van Ouwerkerk, 2017/04/04 13:54:31]

nit: {@link SelectionDelegate}

[Finnur, 2017/04/04 16:13:36]

Done.

+ */
+@RunWith(LocalRobolectricTestRunner.class)
+@Config(manifest = Config.NONE)
+public class SelectionDelegateTest implements SelectionDelegate.SelectionObserver<Object> {
+    private SelectionDelegate<Object> mDelegate;

[Michael van Ouwerkerk, 2017/04/04 13:54:31]

It seems cleaner to track this state on a per-test-method level, and avoid
making SelectionDelegateTest implement the observer interface.

[Finnur, 2017/04/04 16:13:36]

Done.

+
+    private final Object mData1 = new Object();
+    private final Object mData2 = new Object();
+    private final Object mData3 = new Object();
+
+    private List<Object> mSelectedItems;

[Michael van Ouwerkerk, 2017/04/04 13:54:31]

Same for this member, I'd avoid changing member state.

[Finnur, 2017/04/04 16:13:36]

Done.

+
+    // SelectionDelegate.SelectionObserver:
+
+    public void onSelectionStateChange(List<Object> selectedItems) {
+        mSelectedItems = selectedItems;
+        assertEquals(selectedItems, mDelegate.getSelectedItems());
+    }
+
+    @Test
+    public void testSelectionDelegateSingle() {
+        mDelegate = new SelectionDelegate<Object>();
+        mDelegate.setSingleSelectionMode();
+
+        mDelegate.addObserver(this);
+
+        // Starting state, nothing is selected.
+        assertEquals(false, mDelegate.isItemSelected(mData1));

[Michael van Ouwerkerk, 2017/04/04 13:54:31]

Use assertFalse and assertTrue.

[Finnur, 2017/04/04 16:13:36]

Done.

+        assertEquals(false, mDelegate.isSelectionEnabled());
+
+        // Select first item and verify selection.
+        mDelegate.toggleSelectionForItem(mData1);
+        assertEquals(1, mSelectedItems.size());
+        assertEquals(true, mDelegate.isItemSelected(mData1));
+        assertEquals(true, mDelegate.isSelectionEnabled());
+
+        // Select second item, first item gets unselected.
+        mDelegate.toggleSelectionForItem(mData2);
+        assertEquals(1, mSelectedItems.size());
+        assertEquals(false, mDelegate.isItemSelected(mData1));
+        assertEquals(true, mDelegate.isItemSelected(mData2));
+        assertEquals(true, mDelegate.isSelectionEnabled());
+
+        // Unselect second item.
+        mDelegate.toggleSelectionForItem(mData2);
+        assertEquals(0, mSelectedItems.size());
+        assertEquals(false, mDelegate.isItemSelected(mData2));
+        assertEquals(false, mDelegate.isSelectionEnabled());
+
+        // Test clearing selection.
+        mDelegate.toggleSelectionForItem(mData1);
+        mDelegate.clearSelection();
+        assertEquals(0, mSelectedItems.size());
+        assertEquals(false, mDelegate.isItemSelected(mData2));
+        assertEquals(false, mDelegate.isSelectionEnabled());
+
+        mDelegate.removeObserver(this);
+    }
+
+    @Test
+    public void testSelectionDelegateMulti() {
+        mDelegate = new SelectionDelegate<Object>();
+
+        mDelegate.addObserver(this);
+
+        // Starting state, nothing is selected.
+        assertEquals(false, mDelegate.isItemSelected(mData1));
+        assertEquals(false, mDelegate.isSelectionEnabled());
+
+        // Select first item and verify selection.
+        mDelegate.toggleSelectionForItem(mData1);
+        assertEquals(1, mSelectedItems.size());
+        assertEquals(true, mDelegate.isItemSelected(mData1));
+        assertEquals(true, mDelegate.isSelectionEnabled());
+
+        // Select second item, first item does not get unselected.
+        mDelegate.toggleSelectionForItem(mData2);
+        assertEquals(2, mSelectedItems.size());
+        assertEquals(true, mDelegate.isItemSelected(mData1));
+        assertEquals(true, mDelegate.isItemSelected(mData2));
+        assertEquals(true, mDelegate.isSelectionEnabled());
+
+        // Unselect second item.
+        mDelegate.toggleSelectionForItem(mData2);
+        assertEquals(1, mSelectedItems.size());
+        assertEquals(false, mDelegate.isItemSelected(mData2));
+        assertEquals(true, mDelegate.isItemSelected(mData1));
+        assertEquals(true, mDelegate.isSelectionEnabled());
+
+        // Test clearing selection.
+        mDelegate.clearSelection();
+        assertEquals(0, mSelectedItems.size());
+        assertEquals(false, mDelegate.isItemSelected(mData1));
+        assertEquals(false, mDelegate.isItemSelected(mData2));
+        assertEquals(false, mDelegate.isSelectionEnabled());
+
+        mDelegate.removeObserver(this);
+    }
+}