diff --git a/tests/src/com/android/documentsui/BandSelectModelTest.java b/tests/src/com/android/documentsui/BandSelectModelTest.java
new file mode 100644
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+++ b/tests/src/com/android/documentsui/BandSelectModelTest.java
@@ -0,0 +1,286 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.documentsui;
+
+import static org.junit.Assert.*;
+
+import com.android.documentsui.MultiSelectManager.BandSelectModel;
+
+import android.graphics.Point;
+import android.graphics.Rect;
+import android.support.v7.widget.RecyclerView.OnScrollListener;
+import android.util.SparseBooleanArray;
+
+import org.junit.After;
+import org.junit.Test;
+
+public class BandSelectModelTest {
+
+    private static final int VIEW_PADDING_PX = 5;
+    private static final int CHILD_VIEW_EDGE_PX = 100;
+    private static final int VIEWPORT_HEIGHT = 500;
+
+    private static BandSelectModel model;
+    private static TestHelper helper;
+    private static SparseBooleanArray lastSelection;
+    private static int viewWidth;
+
+    private static void setUp(int numChildren, int numColumns) {
+        helper = new TestHelper(numChildren, numColumns);
+        viewWidth = VIEW_PADDING_PX + numColumns * (VIEW_PADDING_PX + CHILD_VIEW_EDGE_PX);
+        model = new BandSelectModel(helper);
+        model.addOnSelectionChangedListener(new BandSelectModel.OnSelectionChangedListener() {
+
+            @Override
+            public void onSelectionChanged(SparseBooleanArray updatedSelection) {
+                lastSelection = updatedSelection;
+            }
+        });
+    }
+
+    @After
+    public void tearDown() {
+        model = null;
+        helper = null;
+        lastSelection = null;
+    }
+
+    @Test
+    public void testSelectionLeftOfItems() {
+        setUp(20, 5);
+        model.startSelection(new Point(0, 10));
+        model.resizeSelection(new Point(1, 11));
+        assertSelected(new int[0]);
+        assertEquals(BandSelectModel.NOT_SET, model.getPositionNearestOrigin());
+    }
+
+    @Test
+    public void testSelectionRightOfItems() {
+        setUp(20, 4);
+        model.startSelection(new Point(viewWidth - 1, 10));
+        model.resizeSelection(new Point(viewWidth - 2, 11));
+        assertSelected(new int[0]);
+        assertEquals(BandSelectModel.NOT_SET, model.getPositionNearestOrigin());
+    }
+
+    @Test
+    public void testSelectionAboveItems() {
+        setUp(20, 4);
+        model.startSelection(new Point(10, 0));
+        model.resizeSelection(new Point(11, 1));
+        assertSelected(new int[0]);
+        assertEquals(BandSelectModel.NOT_SET, model.getPositionNearestOrigin());
+    }
+
+    @Test
+    public void testSelectionBelowItems() {
+        setUp(5, 4);
+        model.startSelection(new Point(10, VIEWPORT_HEIGHT - 1));
+        model.resizeSelection(new Point(11, VIEWPORT_HEIGHT - 2));
+        assertSelected(new int[0]);
+        assertEquals(BandSelectModel.NOT_SET, model.getPositionNearestOrigin());
+    }
+
+    @Test
+    public void testVerticalSelectionBetweenItems() {
+        setUp(20, 4);
+        model.startSelection(new Point(106, 0));
+        model.resizeSelection(new Point(107, 200));
+        assertSelected(new int[0]);
+        assertEquals(BandSelectModel.NOT_SET, model.getPositionNearestOrigin());
+    }
+
+    @Test
+    public void testHorizontalSelectionBetweenItems() {
+        setUp(20, 4);
+        model.startSelection(new Point(0, 105));
+        model.resizeSelection(new Point(200, 106));
+        assertSelected(new int[0]);
+        assertEquals(BandSelectModel.NOT_SET, model.getPositionNearestOrigin());
+    }
+
+    @Test
+    public void testGrowingAndShrinkingSelection() {
+        setUp(20, 4);
+        model.startSelection(new Point(0, 0));
+        model.resizeSelection(new Point(5, 5));
+        assertSelected(new int[] {0});
+        model.resizeSelection(new Point(109, 109));
+        assertSelected(new int[] {0});
+        model.resizeSelection(new Point(110, 109));
+        assertSelected(new int[] {0, 1});
+        model.resizeSelection(new Point(110, 110));
+        assertSelected(new int[] {0, 1, 4, 5});
+        model.resizeSelection(new Point(214, 214));
+        assertSelected(new int[] {0, 1, 4, 5});
+        model.resizeSelection(new Point(215, 214));
+        assertSelected(new int[] {0, 1, 2, 4, 5, 6});
+        model.resizeSelection(new Point(214, 214));
+        assertSelected(new int[] {0, 1, 4, 5});
+        model.resizeSelection(new Point(110, 110));
+        assertSelected(new int[] {0, 1, 4, 5});
+        model.resizeSelection(new Point(110, 109));
+        assertSelected(new int[] {0, 1});
+        model.resizeSelection(new Point(109, 109));
+        assertSelected(new int[] {0});
+        model.resizeSelection(new Point(5, 5));
+        assertSelected(new int[] {0});
+        model.resizeSelection(new Point(0, 0));
+        assertSelected(new int[0]);
+        assertEquals(BandSelectModel.NOT_SET, model.getPositionNearestOrigin());
+    }
+
+    @Test
+    public void testSelectionMovingAroundOrigin() {
+        setUp(16, 4);
+        model.startSelection(new Point(210, 210));
+        model.resizeSelection(new Point(viewWidth - 1, 0));
+        assertSelected(new int[] {2, 3, 6, 7});
+        model.resizeSelection(new Point(0, 0));
+        assertSelected(new int[] {0, 1, 4, 5});
+        model.resizeSelection(new Point(0, 420));
+        assertSelected(new int[] {8, 9, 12, 13});
+        model.resizeSelection(new Point(viewWidth - 1, 420));
+        assertSelected(new int[] {10, 11, 14, 15});
+        assertEquals(10, model.getPositionNearestOrigin());
+    }
+
+    @Test
+    public void testScrollingBandSelect() {
+        setUp(40, 4);
+        model.startSelection(new Point(0, 0));
+        model.resizeSelection(new Point(100, VIEWPORT_HEIGHT - 1));
+        assertSelected(new int[] {0, 4, 8, 12, 16});
+        scroll(CHILD_VIEW_EDGE_PX);
+        assertSelected(new int[] {0, 4, 8, 12, 16, 20});
+        model.resizeSelection(new Point(200, VIEWPORT_HEIGHT - 1));
+        assertSelected(new int[] {0, 1, 4, 5, 8, 9, 12, 13, 16, 17, 20, 21});
+        scroll(CHILD_VIEW_EDGE_PX);
+        assertSelected(new int[] {0, 1, 4, 5, 8, 9, 12, 13, 16, 17, 20, 21, 24, 25});
+        scroll(-2 * CHILD_VIEW_EDGE_PX);
+        assertSelected(new int[] {0, 1, 4, 5, 8, 9, 12, 13, 16, 17});
+        model.resizeSelection(new Point(100, VIEWPORT_HEIGHT - 1));
+        assertSelected(new int[] {0, 4, 8, 12, 16});
+        assertEquals(0, model.getPositionNearestOrigin());
+    }
+
+    private static void assertSelected(int[] selectedPositions) {
+        assertEquals(selectedPositions.length, lastSelection.size());
+        for (int position : selectedPositions) {
+            assertTrue(lastSelection.get(position));
+        }
+    }
+
+    private static void scroll(int dy) {
+        assertTrue(helper.verticalOffset + VIEWPORT_HEIGHT + dy <= helper.getTotalHeight());
+        helper.verticalOffset += dy;
+        model.onScrolled(null, 0, dy);
+    }
+
+    private static final class TestHelper implements MultiSelectManager.BandModelHelper {
+
+        public int horizontalOffset = 0;
+        public int verticalOffset = 0;
+        private final int mNumColumns;
+        private final int mNumRows;
+        private final int mNumChildren;
+
+        public TestHelper(int numChildren, int numColumns) {
+            mNumChildren = numChildren;
+            mNumColumns = numColumns;
+            mNumRows = (int) Math.ceil((double) numChildren / mNumColumns);
+        }
+
+        private int getTotalHeight() {
+            return CHILD_VIEW_EDGE_PX * mNumRows + VIEW_PADDING_PX * (mNumRows + 1);
+        }
+
+        private int getFirstVisibleRowIndex() {
+            return verticalOffset / (CHILD_VIEW_EDGE_PX + VIEW_PADDING_PX);
+        }
+
+        private int getLastVisibleRowIndex() {
+            int lastVisibleRowUncapped =
+                    (VIEWPORT_HEIGHT + verticalOffset - 1) / (CHILD_VIEW_EDGE_PX + VIEW_PADDING_PX);
+            return Math.min(lastVisibleRowUncapped, mNumRows - 1);
+        }
+
+        private int getNumItemsInRow(int index) {
+            assertTrue(index >= 0 && index < mNumRows);
+            if (index == mNumRows - 1 && mNumChildren % mNumColumns != 0) {
+                return mNumChildren % mNumColumns;
+            }
+
+            return mNumColumns;
+        }
+
+        @Override
+        public void addOnScrollListener(OnScrollListener listener) {}
+
+        @Override
+        public void removeOnScrollListener(OnScrollListener listener) {}
+
+        @Override
+        public Point createAbsolutePoint(Point relativePoint) {
+            return new Point(
+                    relativePoint.x + horizontalOffset, relativePoint.y + verticalOffset);
+        }
+
+        @Override
+        public int getVisibleChildCount() {
+            int childCount = 0;
+            for (int i = getFirstVisibleRowIndex(); i <= getLastVisibleRowIndex(); i++) {
+                childCount += getNumItemsInRow(i);
+            }
+            return childCount;
+        }
+
+        @Override
+        public int getAdapterPositionAt(int index) {
+            return index + mNumColumns * (getFirstVisibleRowIndex());
+        }
+
+        @Override
+        public Rect getAbsoluteRectForChildViewAt(int index) {
+            int adapterPosition = getAdapterPositionAt(index);
+            int rowIndex = adapterPosition / mNumColumns;
+            int columnIndex = adapterPosition % mNumColumns;
+
+            Rect rect = new Rect();
+            rect.top = VIEW_PADDING_PX + rowIndex * (CHILD_VIEW_EDGE_PX + VIEW_PADDING_PX);
+            rect.bottom = rect.top + CHILD_VIEW_EDGE_PX - 1;
+            rect.left = VIEW_PADDING_PX + columnIndex * (CHILD_VIEW_EDGE_PX + VIEW_PADDING_PX);
+            rect.right = rect.left + CHILD_VIEW_EDGE_PX - 1;
+            return rect;
+        }
+
+        @Override
+        public int getTotalChildCount() {
+            return mNumChildren;
+        }
+
+        @Override
+        public int getNumColumns() {
+            return mNumColumns;
+        }
+
+        @Override
+        public int getNumRows() {
+            return mNumRows;
+        }
+    }
+}