Adding UserManagerHelper class to SettingsLib.

It's a simple wrapper for adding/removing/switching users.

It provides an interface to register listeners for user changes.

Moving it here to be used in CarSettings and SystemUI for the car.

It's not car-specific, so it could be used by anyone who needs it.

Fixes: 74456332
Bug: 74456744
Test: Unit tests in UserManagerHelperTest.java.
Change-Id: I94b3051ed1e4f96d98e5ab2a7a5a7fa75bc5cade
diff --git a/packages/SettingsLib/src/com/android/settingslib/users/UserManagerHelper.java b/packages/SettingsLib/src/com/android/settingslib/users/UserManagerHelper.java
new file mode 100644
index 0000000..cc69e0e
--- /dev/null
+++ b/packages/SettingsLib/src/com/android/settingslib/users/UserManagerHelper.java
@@ -0,0 +1,367 @@
+/*
+ * Copyright (C) 2018 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.settingslib.users;
+
+import android.app.ActivityManager;
+import android.content.BroadcastReceiver;
+import android.content.Context;
+import android.content.Intent;
+import android.content.IntentFilter;
+import android.content.pm.UserInfo;
+import android.graphics.Bitmap;
+import android.graphics.drawable.BitmapDrawable;
+import android.graphics.drawable.Drawable;
+import android.os.UserHandle;
+import android.os.UserManager;
+import android.util.Log;
+
+import com.android.internal.util.UserIcons;
+
+import java.util.Iterator;
+import java.util.List;
+
+/**
+ * Helper class for managing users, providing methods for removing, adding and switching users.
+ */
+public final class UserManagerHelper {
+    private static final String TAG = "UserManagerHelper";
+    private final Context mContext;
+    private final UserManager mUserManager;
+    private OnUsersUpdateListener mUpdateListener;
+    private final BroadcastReceiver mUserChangeReceiver = new BroadcastReceiver() {
+        @Override
+        public void onReceive(Context context, Intent intent) {
+            mUpdateListener.onUsersUpdate();
+        }
+    };
+
+    public UserManagerHelper(Context context) {
+        mContext = context;
+        mUserManager = (UserManager) mContext.getSystemService(Context.USER_SERVICE);
+    }
+
+    /**
+     * Registers a listener for updates to all users - removing, adding users or changing user info.
+     *
+     * @param listener Instance of {@link OnUsersUpdateListener}.
+     */
+    public void registerOnUsersUpdateListener(OnUsersUpdateListener listener) {
+        mUpdateListener = listener;
+        registerReceiver();
+    }
+
+    /**
+     * Unregisters listener by unregistering {@code BroadcastReceiver}.
+     */
+    public void unregisterOnUsersUpdateListener() {
+        unregisterReceiver();
+    }
+
+    /**
+     * Gets {@link UserInfo} for the current user.
+     *
+     * @return {@link UserInfo} for the current user.
+     */
+    public UserInfo getCurrentUserInfo() {
+        return mUserManager.getUserInfo(UserHandle.myUserId());
+    }
+
+    /**
+     * Gets all the other users on the system that are not the current user.
+     *
+     * @return List of {@code UserInfo} for each user that is not the current user.
+     */
+    public List<UserInfo> getAllUsersExcludesCurrentUser() {
+        List<UserInfo> others = mUserManager.getUsers(true);
+
+        for (Iterator<UserInfo> iterator = others.iterator(); iterator.hasNext(); ) {
+            UserInfo userInfo = iterator.next();
+            if (userInfo.id == UserHandle.myUserId()) {
+                // Remove current user from the list.
+                iterator.remove();
+            }
+        }
+        return others;
+    }
+
+    // User information accessors
+
+    /**
+     * Checks whether the user is system user (admin).
+     *
+     * @param userInfo User to check against system user.
+     * @return {@code true} if system user, {@code false} otherwise.
+     */
+    public boolean userIsSystemUser(UserInfo userInfo) {
+        return userInfo.id == UserHandle.USER_SYSTEM;
+    }
+
+    /**
+     * Returns whether this user can be removed from the system.
+     *
+     * @param userInfo User to be removed
+     * @return {@code true} if they can be removed, {@code false} otherwise.
+     */
+    public boolean userCanBeRemoved(UserInfo userInfo) {
+        return !userIsSystemUser(userInfo);
+    }
+
+    /**
+     * Checks whether passed in user is the user that's currently logged in.
+     *
+     * @param userInfo User to check.
+     * @return {@code true} if current user, {@code false} otherwise.
+     */
+    public boolean userIsCurrentUser(UserInfo userInfo) {
+        return getCurrentUserInfo().id == userInfo.id;
+    }
+
+    // Current user information accessors
+
+    /**
+     * Checks if the current user is a demo user.
+     */
+    public boolean isDemoUser() {
+        return mUserManager.isDemoUser();
+    }
+
+    /**
+     * Checks if the current user is a guest user.
+     */
+    public boolean isGuestUser() {
+        return mUserManager.isGuestUser();
+    }
+
+    /**
+     * Checks if the current user is the system user (User 0).
+     */
+    public boolean isSystemUser() {
+        return mUserManager.isSystemUser();
+    }
+
+    // Current user restriction accessors
+
+    /**
+     * Return whether the current user has a restriction.
+     *
+     * @param restriction Restriction to check. Should be a UserManager.* restriction.
+     * @return Whether that restriction exists for the current user.
+     */
+    public boolean hasUserRestriction(String restriction) {
+        return mUserManager.hasUserRestriction(restriction);
+    }
+
+    /**
+     * Checks if the current user can add new users.
+     */
+    public boolean canAddUsers() {
+        return !hasUserRestriction(UserManager.DISALLOW_ADD_USER);
+    }
+
+    /**
+     * Checks if the current user can remove users.
+     */
+    public boolean canRemoveUsers() {
+        return !hasUserRestriction(UserManager.DISALLOW_REMOVE_USER);
+    }
+
+    /**
+     * Checks if the current user is allowed to switch to another user.
+     */
+    public boolean canSwitchUsers() {
+        return !hasUserRestriction(UserManager.DISALLOW_USER_SWITCH);
+    }
+
+    /**
+     * Checks if the current user can modify accounts. Demo and Guest users cannot modify accounts
+     * even if the DISALLOW_MODIFY_ACCOUNTS restriction is not applied.
+     */
+    public boolean canModifyAccounts() {
+        return !hasUserRestriction(UserManager.DISALLOW_MODIFY_ACCOUNTS) && !isDemoUser()
+                && !isGuestUser();
+    }
+
+    // User actions
+
+    /**
+     * Creates a new user on the system.
+     *
+     * @param userName Name to give to the newly created user.
+     * @return Newly created user.
+     */
+    public UserInfo createNewUser(String userName) {
+        UserInfo user = mUserManager.createUser(userName, 0 /* flags */);
+        if (user == null) {
+            // Couldn't create user, most likely because there are too many, but we haven't
+            // been able to reload the list yet.
+            Log.w(TAG, "can't create user.");
+            return null;
+        }
+        assignDefaultIcon(user);
+        return user;
+    }
+
+    /**
+     * Tries to remove the user that's passed in. System user cannot be removed.
+     * If the user to be removed is current user, it switches to the system user first, and then
+     * removes the user.
+     *
+     * @param userInfo User to be removed
+     * @return {@code true} if user is successfully removed, {@code false} otherwise.
+     */
+    public boolean removeUser(UserInfo userInfo) {
+        if (userInfo.id == UserHandle.USER_SYSTEM) {
+            Log.w(TAG, "User " + userInfo.id + " is system user, could not be removed.");
+            return false;
+        }
+
+        if (userInfo.id == getCurrentUserInfo().id) {
+            switchToUserId(UserHandle.USER_SYSTEM);
+        }
+
+        return mUserManager.removeUser(userInfo.id);
+    }
+
+    /**
+     * Switches (logs in) to another user.
+     *
+     * @param userInfo User to switch to.
+     */
+    public void switchToUser(UserInfo userInfo) {
+        if (userInfo.id == getCurrentUserInfo().id) {
+            return;
+        }
+
+        if (userInfo.isGuest()) {
+            switchToGuest(userInfo.name);
+            return;
+        }
+
+        if (UserManager.isGuestUserEphemeral()) {
+            // If switching from guest, we want to bring up the guest exit dialog instead of
+            // switching
+            UserInfo currUserInfo = getCurrentUserInfo();
+            if (currUserInfo != null && currUserInfo.isGuest()) {
+                return;
+            }
+        }
+
+        switchToUserId(userInfo.id);
+    }
+
+    /**
+     * Creates a guest session and switches into the guest session.
+     *
+     * @param guestName Username for the guest user.
+     */
+    public void switchToGuest(String guestName) {
+        UserInfo guest = mUserManager.createGuest(mContext, guestName);
+        if (guest == null) {
+            // Couldn't create user, most likely because there are too many, but we haven't
+            // been able to reload the list yet.
+            Log.w(TAG, "can't create user.");
+            return;
+        }
+        switchToUserId(guest.id);
+    }
+
+    /**
+     * Gets an icon for the user.
+     *
+     * @param userInfo User for which we want to get the icon.
+     * @return a Bitmap for the icon
+     */
+    public Bitmap getUserIcon(UserInfo userInfo) {
+        Bitmap picture = mUserManager.getUserIcon(userInfo.id);
+
+        if (picture == null) {
+            return assignDefaultIcon(userInfo);
+        }
+
+        return picture;
+    }
+
+    /**
+     * Method for scaling a Bitmap icon to a desirable size.
+     *
+     * @param icon Bitmap to scale.
+     * @param desiredSize Wanted size for the icon.
+     * @return Drawable for the icon, scaled to the new size.
+     */
+    public Drawable scaleUserIcon(Bitmap icon, int desiredSize) {
+        Bitmap scaledIcon = Bitmap.createScaledBitmap(
+                icon, desiredSize, desiredSize, true /* filter */);
+        return new BitmapDrawable(mContext.getResources(), scaledIcon);
+    }
+
+    /**
+     * Sets new Username for the user.
+     *
+     * @param user User whose name should be changed.
+     * @param name New username.
+     */
+    public void setUserName(UserInfo user, String name) {
+        mUserManager.setUserName(user.id, name);
+    }
+
+    private void registerReceiver() {
+        IntentFilter filter = new IntentFilter();
+        filter.addAction(Intent.ACTION_USER_REMOVED);
+        filter.addAction(Intent.ACTION_USER_ADDED);
+        filter.addAction(Intent.ACTION_USER_INFO_CHANGED);
+        mContext.registerReceiverAsUser(mUserChangeReceiver, UserHandle.ALL, filter, null, null);
+    }
+
+    /**
+     * Assigns a default icon to a user according to the user's id.
+     *
+     * @param userInfo User to assign a default icon to.
+     * @return Bitmap that has been assigned to the user.
+     */
+    private Bitmap assignDefaultIcon(UserInfo userInfo) {
+        Bitmap bitmap = UserIcons.convertToBitmap(
+                UserIcons.getDefaultUserIcon(mContext.getResources(), userInfo.id, false));
+        mUserManager.setUserIcon(userInfo.id, bitmap);
+        return bitmap;
+    }
+
+    private void switchToUserId(int id) {
+        try {
+            final ActivityManager am = (ActivityManager)
+                    mContext.getSystemService(Context.ACTIVITY_SERVICE);
+            am.switchUser(id);
+        } catch (Exception e) {
+            Log.e(TAG, "Couldn't switch user.", e);
+        }
+    }
+
+    private void unregisterReceiver() {
+        mContext.unregisterReceiver(mUserChangeReceiver);
+    }
+
+    /**
+     * Interface for listeners that want to register for receiving updates to changes to the users
+     * on the system including removing and adding users, and changing user info.
+     */
+    public interface OnUsersUpdateListener {
+        /**
+         * Method that will get called when users list has been changed.
+         */
+        void onUsersUpdate();
+    }
+}
+
diff --git a/packages/SettingsLib/tests/integ/src/com/android/settingslib/users/UserManagerHelperTest.java b/packages/SettingsLib/tests/integ/src/com/android/settingslib/users/UserManagerHelperTest.java
new file mode 100644
index 0000000..325ef3a
--- /dev/null
+++ b/packages/SettingsLib/tests/integ/src/com/android/settingslib/users/UserManagerHelperTest.java
@@ -0,0 +1,318 @@
+/*
+ * Copyright (C) 2018 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.settingslib.users;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import android.app.ActivityManager;
+import android.content.BroadcastReceiver;
+import android.content.Context;
+import android.content.Intent;
+import android.content.IntentFilter;
+import android.content.pm.UserInfo;
+import android.graphics.Bitmap;
+import android.graphics.drawable.Drawable;
+import android.os.Handler;
+import android.os.UserHandle;
+import android.os.UserManager;
+import android.support.test.InstrumentationRegistry;
+import android.support.test.runner.AndroidJUnit4;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.ArgumentCaptor;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+
+import java.util.ArrayList;
+import java.util.List;
+
+@RunWith(AndroidJUnit4.class)
+public class UserManagerHelperTest {
+    @Mock
+    private Context mContext;
+    @Mock
+    private UserManager mUserManager;
+    @Mock
+    private ActivityManager mActivityManager;
+    @Mock
+    private UserManagerHelper.OnUsersUpdateListener mTestListener;
+
+    private UserManagerHelper mHelper;
+    private UserInfo mCurrentUser;
+    private UserInfo mSystemUser;
+
+    @Before
+    public void setUp() throws Exception {
+        MockitoAnnotations.initMocks(this);
+        when(mContext.getSystemService(Context.USER_SERVICE)).thenReturn(mUserManager);
+        when(mContext.getSystemService(Context.ACTIVITY_SERVICE)).thenReturn(mActivityManager);
+        when(mContext.getResources())
+                .thenReturn(InstrumentationRegistry.getTargetContext().getResources());
+        mHelper = new UserManagerHelper(mContext);
+
+        mCurrentUser = createUserInfoForId(UserHandle.myUserId());
+        mSystemUser = createUserInfoForId(UserHandle.USER_SYSTEM);
+        when(mUserManager.getUserInfo(UserHandle.myUserId())).thenReturn(mCurrentUser);
+    }
+
+    @Test
+    public void testUserIsSystemUser() {
+        UserInfo testInfo = new UserInfo();
+
+        testInfo.id = UserHandle.USER_SYSTEM;
+        assertThat(mHelper.userIsSystemUser(testInfo)).isTrue();
+
+        testInfo.id = UserHandle.USER_SYSTEM + 2; // Make it different than system id.
+        assertThat(mHelper.userIsSystemUser(testInfo)).isFalse();
+    }
+
+    @Test
+    public void testGetAllUsersExcludesCurrentUser() {
+        int currentUser = UserHandle.myUserId();
+
+        UserInfo otherUser1 = createUserInfoForId(currentUser + 1);
+        UserInfo otherUser2 = createUserInfoForId(currentUser - 1);
+        UserInfo otherUser3 = createUserInfoForId(currentUser + 2);
+
+        List<UserInfo> testUsers = new ArrayList<>();
+        testUsers.add(otherUser1);
+        testUsers.add(otherUser2);
+        testUsers.add(mCurrentUser);
+        testUsers.add(otherUser3);
+
+        when(mUserManager.getUsers(true)).thenReturn(testUsers);
+
+        // Should return 3 users that don't have currentUser id.
+        assertThat(mHelper.getAllUsersExcludesCurrentUser().size()).isEqualTo(3);
+        // Should not contain current user.
+        assertThat(mHelper.getAllUsersExcludesCurrentUser()).doesNotContain(mCurrentUser);
+        // Should contain non-current users.
+        assertThat(mHelper.getAllUsersExcludesCurrentUser()).contains(otherUser1);
+        assertThat(mHelper.getAllUsersExcludesCurrentUser()).contains(otherUser2);
+        assertThat(mHelper.getAllUsersExcludesCurrentUser()).contains(otherUser3);
+    }
+
+    @Test
+    public void testUserCanBeRemoved() {
+        UserInfo testInfo = new UserInfo();
+
+        // System user cannot be removed.
+        testInfo.id = UserHandle.USER_SYSTEM;
+        assertThat(mHelper.userCanBeRemoved(testInfo)).isFalse();
+
+        testInfo.id = UserHandle.USER_SYSTEM + 2; // Make it different than system id.
+        assertThat(mHelper.userCanBeRemoved(testInfo)).isTrue();
+    }
+
+    @Test
+    public void testUserIsCurrentUser() {
+        UserInfo testInfo = new UserInfo();
+
+        // System user cannot be removed.
+        testInfo.id = UserHandle.myUserId();
+        assertThat(mHelper.userIsCurrentUser(testInfo)).isTrue();
+
+        testInfo.id = UserHandle.myUserId() + 2;
+        assertThat(mHelper.userIsCurrentUser(testInfo)).isFalse();
+    }
+
+    @Test
+    public void testCanAddUsers() {
+        when(mUserManager.hasUserRestriction(UserManager.DISALLOW_ADD_USER)).thenReturn(false);
+        assertThat(mHelper.canAddUsers()).isTrue();
+
+        when(mUserManager.hasUserRestriction(UserManager.DISALLOW_ADD_USER)).thenReturn(true);
+        assertThat(mHelper.canAddUsers()).isFalse();
+    }
+
+    @Test
+    public void testCanRemoveUsers() {
+        when(mUserManager.hasUserRestriction(UserManager.DISALLOW_REMOVE_USER)).thenReturn(false);
+        assertThat(mHelper.canRemoveUsers()).isTrue();
+
+        when(mUserManager.hasUserRestriction(UserManager.DISALLOW_REMOVE_USER)).thenReturn(true);
+        assertThat(mHelper.canRemoveUsers()).isFalse();
+    }
+
+    @Test
+    public void testCanSwitchUsers() {
+        when(mUserManager.hasUserRestriction(UserManager.DISALLOW_USER_SWITCH)).thenReturn(false);
+        assertThat(mHelper.canSwitchUsers()).isTrue();
+
+        when(mUserManager.hasUserRestriction(UserManager.DISALLOW_USER_SWITCH)).thenReturn(true);
+        assertThat(mHelper.canSwitchUsers()).isFalse();
+    }
+
+    @Test
+    public void testGuestCannotModifyAccounts() {
+        assertThat(mHelper.canModifyAccounts()).isTrue();
+
+        when(mUserManager.isGuestUser()).thenReturn(true);
+        assertThat(mHelper.canModifyAccounts()).isFalse();
+    }
+
+    @Test
+    public void testDemoUserCannotModifyAccounts() {
+        assertThat(mHelper.canModifyAccounts()).isTrue();
+
+        when(mUserManager.isDemoUser()).thenReturn(true);
+        assertThat(mHelper.canModifyAccounts()).isFalse();
+    }
+
+    @Test
+    public void testUserWithDisallowModifyAccountsRestrictionCannotModifyAccounts() {
+        assertThat(mHelper.canModifyAccounts()).isTrue();
+
+        when(mUserManager.hasUserRestriction(UserManager.DISALLOW_MODIFY_ACCOUNTS))
+                .thenReturn(true);
+        assertThat(mHelper.canModifyAccounts()).isFalse();
+    }
+
+    @Test
+    public void testCreateNewUser() {
+        // Verify createUser on UserManager gets called.
+        mHelper.createNewUser("Test User");
+        verify(mUserManager).createUser("Test User", 0);
+
+        when(mUserManager.createUser("Test User", 0)).thenReturn(null);
+        assertThat(mHelper.createNewUser("Test User")).isNull();
+
+        UserInfo newUser = new UserInfo();
+        newUser.name = "Test User";
+        when(mUserManager.createUser("Test User", 0)).thenReturn(newUser);
+        assertThat(mHelper.createNewUser("Test User")).isEqualTo(newUser);
+    }
+
+    @Test
+    public void testRemoveUser() {
+        // Cannot remove system user.
+        assertThat(mHelper.removeUser(mSystemUser)).isFalse();
+
+        // Removing current user, calls "switch" to system user.
+        mHelper.removeUser(mCurrentUser);
+        verify(mActivityManager).switchUser(UserHandle.USER_SYSTEM);
+        verify(mUserManager).removeUser(mCurrentUser.id);
+
+        // Removing non-current, non-system user, simply calls removeUser.
+        UserInfo userToRemove = createUserInfoForId(mCurrentUser.id + 2);
+        mHelper.removeUser(userToRemove);
+        verify(mUserManager).removeUser(mCurrentUser.id + 2);
+    }
+
+    @Test
+    public void testSwitchToUser() {
+        // Switching to current user doesn't do anything.
+        mHelper.switchToUser(mCurrentUser);
+        verify(mActivityManager, never()).switchUser(mCurrentUser.id);
+
+        // Switching to Guest calls createGuest.
+        UserInfo guestInfo = new UserInfo(mCurrentUser.id + 1, "Test Guest", UserInfo.FLAG_GUEST);
+        mHelper.switchToUser(guestInfo);
+        verify(mUserManager).createGuest(mContext, "Test Guest");
+
+        // Switching to non-current, non-guest user, simply calls switchUser.
+        UserInfo userToSwitchTo = new UserInfo(mCurrentUser.id + 5, "Test User", 0);
+        mHelper.switchToUser(userToSwitchTo);
+        verify(mActivityManager).switchUser(mCurrentUser.id + 5);
+    }
+
+    @Test
+    public void testSwitchToGuest() {
+        mHelper.switchToGuest("Test Guest");
+        verify(mUserManager).createGuest(mContext, "Test Guest");
+
+        UserInfo guestInfo = new UserInfo(mCurrentUser.id + 2, "Test Guest", UserInfo.FLAG_GUEST);
+        when(mUserManager.createGuest(mContext, "Test Guest")).thenReturn(guestInfo);
+        mHelper.switchToGuest("Test Guest");
+        verify(mActivityManager).switchUser(mCurrentUser.id + 2);
+    }
+
+    @Test
+    public void testGetUserIcon() {
+        mHelper.getUserIcon(mCurrentUser);
+        verify(mUserManager).getUserIcon(mCurrentUser.id);
+    }
+
+    @Test
+    public void testScaleUserIcon() {
+        Bitmap fakeIcon = Bitmap.createBitmap(100, 100, Bitmap.Config.ARGB_8888);
+        Drawable scaledIcon = mHelper.scaleUserIcon(fakeIcon, 300);
+        assertThat(scaledIcon.getIntrinsicWidth()).isEqualTo(300);
+        assertThat(scaledIcon.getIntrinsicHeight()).isEqualTo(300);
+    }
+
+    @Test
+    public void testSetUserName() {
+        UserInfo testInfo = createUserInfoForId(mCurrentUser.id + 3);
+        mHelper.setUserName(testInfo, "New Test Name");
+        verify(mUserManager).setUserName(mCurrentUser.id + 3, "New Test Name");
+    }
+
+    @Test
+    public void testRegisterUserChangeReceiver() {
+        mHelper.registerOnUsersUpdateListener(mTestListener);
+
+        ArgumentCaptor<BroadcastReceiver> receiverCaptor =
+                ArgumentCaptor.forClass(BroadcastReceiver.class);
+        ArgumentCaptor<UserHandle> handleCaptor = ArgumentCaptor.forClass(UserHandle.class);
+        ArgumentCaptor<IntentFilter> filterCaptor = ArgumentCaptor.forClass(IntentFilter.class);
+        ArgumentCaptor<String> permissionCaptor = ArgumentCaptor.forClass(String.class);
+        ArgumentCaptor<Handler> handlerCaptor = ArgumentCaptor.forClass(Handler.class);
+
+        verify(mContext).registerReceiverAsUser(
+                receiverCaptor.capture(),
+                handleCaptor.capture(),
+                filterCaptor.capture(),
+                permissionCaptor.capture(),
+                handlerCaptor.capture());
+
+        // Verify we're listening to Intents from ALL users.
+        assertThat(handleCaptor.getValue()).isEqualTo(UserHandle.ALL);
+
+        // Verify the presence of each intent in the filter.
+        // Verify the exact number of filters. Every time a new intent is added, this test should
+        // get updated.
+        assertThat(filterCaptor.getValue().countActions()).isEqualTo(3);
+        assertThat(filterCaptor.getValue().hasAction(Intent.ACTION_USER_REMOVED)).isTrue();
+        assertThat(filterCaptor.getValue().hasAction(Intent.ACTION_USER_ADDED)).isTrue();
+        assertThat(filterCaptor.getValue().hasAction(Intent.ACTION_USER_INFO_CHANGED)).isTrue();
+
+        // Verify that calling the receiver calls the listener.
+        receiverCaptor.getValue().onReceive(mContext, new Intent());
+        verify(mTestListener).onUsersUpdate();
+
+        assertThat(permissionCaptor.getValue()).isNull();
+        assertThat(handlerCaptor.getValue()).isNull();
+
+
+        // Unregister the receiver.
+        mHelper.unregisterOnUsersUpdateListener();
+        verify(mContext).unregisterReceiver(receiverCaptor.getValue());
+    }
+
+    private UserInfo createUserInfoForId(int id) {
+        UserInfo userInfo = new UserInfo();
+        userInfo.id = id;
+        return userInfo;
+    }
+}