diff --git a/libs/WindowManager/Shell/tests/unittest/src/com/android/wm/shell/bubbles/BubblePositionerTest.java b/libs/WindowManager/Shell/tests/unittest/src/com/android/wm/shell/bubbles/BubblePositionerTest.java
new file mode 100644
index 0000000..5f72397
--- /dev/null
+++ b/libs/WindowManager/Shell/tests/unittest/src/com/android/wm/shell/bubbles/BubblePositionerTest.java
@@ -0,0 +1,271 @@
+/*
+ * Copyright (C) 2023 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.wm.shell.bubbles;
+
+import static android.content.res.Configuration.ORIENTATION_LANDSCAPE;
+import static android.content.res.Configuration.ORIENTATION_PORTRAIT;
+import static android.view.View.LAYOUT_DIRECTION_LTR;
+import static android.view.View.LAYOUT_DIRECTION_RTL;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import static org.mockito.ArgumentMatchers.anyInt;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.when;
+
+import android.content.res.Configuration;
+import android.graphics.Insets;
+import android.graphics.PointF;
+import android.graphics.Rect;
+import android.graphics.RectF;
+import android.testing.AndroidTestingRunner;
+import android.testing.TestableLooper;
+import android.testing.TestableResources;
+import android.view.WindowInsets;
+import android.view.WindowManager;
+import android.view.WindowMetrics;
+
+import androidx.test.filters.SmallTest;
+
+import com.android.wm.shell.R;
+import com.android.wm.shell.ShellTestCase;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+
+/**
+ * Tests operations and the resulting state managed by {@link BubblePositioner}.
+ */
+@SmallTest
+@RunWith(AndroidTestingRunner.class)
+@TestableLooper.RunWithLooper(setAsMainLooper = true)
+public class BubblePositionerTest extends ShellTestCase {
+
+    private static final int MIN_WIDTH_FOR_TABLET = 600;
+
+    private BubblePositioner mPositioner;
+    private Configuration mConfiguration;
+
+    @Mock
+    private WindowManager mWindowManager;
+    @Mock
+    private WindowMetrics mWindowMetrics;
+
+    @Before
+    public void setUp() {
+        MockitoAnnotations.initMocks(this);
+
+        mConfiguration = spy(new Configuration());
+        TestableResources testableResources = mContext.getOrCreateTestableResources();
+        testableResources.overrideConfiguration(mConfiguration);
+
+        mPositioner = new BubblePositioner(mContext, mWindowManager);
+    }
+
+    @Test
+    public void testUpdate() {
+        Insets insets = Insets.of(10, 20, 5, 15);
+        Rect screenBounds = new Rect(0, 0, 1000, 1200);
+        Rect availableRect = new Rect(screenBounds);
+        availableRect.inset(insets);
+
+        new WindowManagerConfig()
+                .setInsets(insets)
+                .setScreenBounds(screenBounds)
+                .setUpConfig();
+        mPositioner.update();
+
+        assertThat(mPositioner.getAvailableRect()).isEqualTo(availableRect);
+        assertThat(mPositioner.isLandscape()).isFalse();
+        assertThat(mPositioner.isLargeScreen()).isFalse();
+        assertThat(mPositioner.getInsets()).isEqualTo(insets);
+    }
+
+    @Test
+    public void testShowBubblesVertically_phonePortrait() {
+        new WindowManagerConfig().setOrientation(ORIENTATION_PORTRAIT).setUpConfig();
+        mPositioner.update();
+
+        assertThat(mPositioner.showBubblesVertically()).isFalse();
+    }
+
+    @Test
+    public void testShowBubblesVertically_phoneLandscape() {
+        new WindowManagerConfig().setOrientation(ORIENTATION_LANDSCAPE).setUpConfig();
+        mPositioner.update();
+
+        assertThat(mPositioner.isLandscape()).isTrue();
+        assertThat(mPositioner.showBubblesVertically()).isTrue();
+    }
+
+    @Test
+    public void testShowBubblesVertically_tablet() {
+        new WindowManagerConfig().setLargeScreen().setUpConfig();
+        mPositioner.update();
+
+        assertThat(mPositioner.showBubblesVertically()).isTrue();
+    }
+
+    /** If a resting position hasn't been set, calling it will return the default position. */
+    @Test
+    public void testGetRestingPosition_returnsDefaultPosition() {
+        new WindowManagerConfig().setUpConfig();
+        mPositioner.update();
+
+        PointF restingPosition = mPositioner.getRestingPosition();
+        PointF defaultPosition = mPositioner.getDefaultStartPosition();
+
+        assertThat(restingPosition).isEqualTo(defaultPosition);
+    }
+
+    /** If a resting position has been set, it'll return that instead of the default position. */
+    @Test
+    public void testGetRestingPosition_returnsRestingPosition() {
+        new WindowManagerConfig().setUpConfig();
+        mPositioner.update();
+
+        PointF restingPosition = new PointF(100, 100);
+        mPositioner.setRestingPosition(restingPosition);
+
+        assertThat(mPositioner.getRestingPosition()).isEqualTo(restingPosition);
+    }
+
+    /** Test that the default resting position on phone is in upper left. */
+    @Test
+    public void testGetRestingPosition_bubble_onPhone() {
+        new WindowManagerConfig().setUpConfig();
+        mPositioner.update();
+
+        RectF allowableStackRegion =
+                mPositioner.getAllowableStackPositionRegion(1 /* bubbleCount */);
+        PointF restingPosition = mPositioner.getRestingPosition();
+
+        assertThat(restingPosition.x).isEqualTo(allowableStackRegion.left);
+        assertThat(restingPosition.y).isEqualTo(getDefaultYPosition());
+    }
+
+    @Test
+    public void testGetRestingPosition_bubble_onPhone_RTL() {
+        new WindowManagerConfig().setLayoutDirection(LAYOUT_DIRECTION_RTL).setUpConfig();
+        mPositioner.update();
+
+        RectF allowableStackRegion =
+                mPositioner.getAllowableStackPositionRegion(1 /* bubbleCount */);
+        PointF restingPosition = mPositioner.getRestingPosition();
+
+        assertThat(restingPosition.x).isEqualTo(allowableStackRegion.right);
+        assertThat(restingPosition.y).isEqualTo(getDefaultYPosition());
+    }
+
+    /** Test that the default resting position on tablet is middle left. */
+    @Test
+    public void testGetRestingPosition_chatBubble_onTablet() {
+        new WindowManagerConfig().setLargeScreen().setUpConfig();
+        mPositioner.update();
+
+        RectF allowableStackRegion =
+                mPositioner.getAllowableStackPositionRegion(1 /* bubbleCount */);
+        PointF restingPosition = mPositioner.getRestingPosition();
+
+        assertThat(restingPosition.x).isEqualTo(allowableStackRegion.left);
+        assertThat(restingPosition.y).isEqualTo(getDefaultYPosition());
+    }
+
+    @Test
+    public void testGetRestingPosition_chatBubble_onTablet_RTL() {
+        new WindowManagerConfig().setLargeScreen().setLayoutDirection(
+                LAYOUT_DIRECTION_RTL).setUpConfig();
+        mPositioner.update();
+
+        RectF allowableStackRegion =
+                mPositioner.getAllowableStackPositionRegion(1 /* bubbleCount */);
+        PointF restingPosition = mPositioner.getRestingPosition();
+
+        assertThat(restingPosition.x).isEqualTo(allowableStackRegion.right);
+        assertThat(restingPosition.y).isEqualTo(getDefaultYPosition());
+    }
+
+    /**
+     * Calculates the Y position bubbles should be placed based on the config. Based on
+     * the calculations in {@link BubblePositioner#getDefaultStartPosition()} and
+     * {@link BubbleStackView.RelativeStackPosition}.
+     */
+    private float getDefaultYPosition() {
+        final float desiredY = mContext.getResources().getDimensionPixelOffset(
+                        R.dimen.bubble_stack_starting_offset_y);
+        float offsetPercent = desiredY / mPositioner.getAvailableRect().height();
+        offsetPercent = Math.max(0f, Math.min(1f, offsetPercent));
+        final RectF allowableStackRegion =
+                mPositioner.getAllowableStackPositionRegion(1 /* bubbleCount */);
+        return allowableStackRegion.top + allowableStackRegion.height() * offsetPercent;
+    }
+
+    /**
+     * Sets up window manager to return config values based on what you need for the test.
+     * By default it sets up a portrait phone without any insets.
+     */
+    private class WindowManagerConfig {
+        private Rect mScreenBounds = new Rect(0, 0, 1000, 2000);
+        private boolean mIsLargeScreen = false;
+        private int mOrientation = ORIENTATION_PORTRAIT;
+        private int mLayoutDirection = LAYOUT_DIRECTION_LTR;
+        private Insets mInsets = Insets.of(0, 0, 0, 0);
+
+        public WindowManagerConfig setScreenBounds(Rect screenBounds) {
+            mScreenBounds = screenBounds;
+            return this;
+        }
+
+        public WindowManagerConfig setLargeScreen() {
+            mIsLargeScreen = true;
+            return this;
+        }
+
+        public WindowManagerConfig setOrientation(int orientation) {
+            mOrientation = orientation;
+            return this;
+        }
+
+        public WindowManagerConfig setLayoutDirection(int layoutDirection) {
+            mLayoutDirection = layoutDirection;
+            return this;
+        }
+
+        public WindowManagerConfig setInsets(Insets insets) {
+            mInsets = insets;
+            return this;
+        }
+
+        public void setUpConfig() {
+            mConfiguration.smallestScreenWidthDp = mIsLargeScreen
+                    ? MIN_WIDTH_FOR_TABLET
+                    : MIN_WIDTH_FOR_TABLET - 1;
+            mConfiguration.orientation = mOrientation;
+
+            when(mConfiguration.getLayoutDirection()).thenReturn(mLayoutDirection);
+            WindowInsets windowInsets = mock(WindowInsets.class);
+            when(windowInsets.getInsetsIgnoringVisibility(anyInt())).thenReturn(mInsets);
+            when(mWindowMetrics.getWindowInsets()).thenReturn(windowInsets);
+            when(mWindowMetrics.getBounds()).thenReturn(mScreenBounds);
+            when(mWindowManager.getCurrentWindowMetrics()).thenReturn(mWindowMetrics);
+        }
+    }
+}