### Question:
BackupManagerService { @VisibleForTesting public SparseArray<UserBackupManagerService> getServiceUsers() { return mServiceUsers; } BackupManagerService(
            Context context, Trampoline trampoline, HandlerThread backupThread); @VisibleForTesting SparseArray<UserBackupManagerService> getServiceUsers(); void dataChanged(@UserIdInt int userId, String packageName); void agentConnected(@UserIdInt int userId, String packageName, IBinder agentBinder); void agentDisconnected(@UserIdInt int userId, String packageName); void opComplete(@UserIdInt int userId, int token, long result); void initializeTransports(
            @UserIdInt int userId, String[] transportNames, IBackupObserver observer); void clearBackupData(@UserIdInt int userId, String transportName, String packageName); @Nullable String getCurrentTransport(@UserIdInt int userId); @Nullable ComponentName getCurrentTransportComponent(@UserIdInt int userId); @Nullable String[] listAllTransports(@UserIdInt int userId); @Nullable ComponentName[] listAllTransportComponents(@UserIdInt int userId); @Nullable String[] getTransportWhitelist(); void updateTransportAttributes(
            @UserIdInt int userId,
            ComponentName transportComponent,
            String name,
            @Nullable Intent configurationIntent,
            String currentDestinationString,
            @Nullable Intent dataManagementIntent,
            CharSequence dataManagementLabel); @Deprecated @Nullable String selectBackupTransport(@UserIdInt int userId, String transportName); void selectBackupTransportAsync(
            @UserIdInt int userId,
            ComponentName transportComponent,
            ISelectBackupTransportCallback listener); @Nullable Intent getConfigurationIntent(@UserIdInt int userId, String transportName); void setAncestralSerialNumber(long ancestralSerialNumber); @Nullable UserHandle getUserForAncestralSerialNumber(long ancestralSerialNumber); @Nullable String getDestinationString(@UserIdInt int userId, String transportName); @Nullable Intent getDataManagementIntent(@UserIdInt int userId, String transportName); @Nullable CharSequence getDataManagementLabel(@UserIdInt int userId, String transportName); void setBackupEnabled(@UserIdInt int userId, boolean enable); void setAutoRestore(@UserIdInt int userId, boolean autoRestore); boolean isBackupEnabled(@UserIdInt int userId); boolean isAppEligibleForBackup(@UserIdInt int userId, String packageName); @Nullable String[] filterAppsEligibleForBackup(@UserIdInt int userId, String[] packages); void backupNow(@UserIdInt int userId); int requestBackup(
            @UserIdInt int userId,
            String[] packages,
            IBackupObserver observer,
            IBackupManagerMonitor monitor,
            int flags); void cancelBackups(@UserIdInt int userId); boolean beginFullBackup(@UserIdInt int userId, FullBackupJob scheduledJob); void endFullBackup(@UserIdInt int userId); void fullTransportBackup(@UserIdInt int userId, String[] packageNames); void restoreAtInstall(@UserIdInt int userId, String packageName, int token); @Nullable IRestoreSession beginRestoreSession(
            @UserIdInt int userId, String packageName, String transportName); long getAvailableRestoreToken(@UserIdInt int userId, String packageName); boolean setBackupPassword(String currentPassword, String newPassword); boolean hasBackupPassword(); void adbBackup(
            @UserIdInt int userId,
            ParcelFileDescriptor fd,
            boolean includeApks,
            boolean includeObbs,
            boolean includeShared,
            boolean doWidgets,
            boolean doAllApps,
            boolean includeSystem,
            boolean doCompress,
            boolean doKeyValue,
            String[] packageNames); void adbRestore(@UserIdInt int userId, ParcelFileDescriptor fd); void acknowledgeAdbBackupOrRestore(
            @UserIdInt int userId,
            int token,
            boolean allow,
            String currentPassword,
            String encryptionPassword,
            IFullBackupRestoreObserver observer); void dump(FileDescriptor fd, PrintWriter pw, String[] args); static final String TAG; static final boolean DEBUG; static final boolean MORE_DEBUG; static final boolean DEBUG_SCHEDULING; }### Answer:
@Test public void testConstructor_doesNotRegisterUsers() throws Exception { BackupManagerService backupManagerService = createService(); assertThat(backupManagerService.getServiceUsers().size()).isEqualTo(0); }