StudentHelper { public static String extractDeviceIdFromUniqueId(String uniqueId) { String[] uniqueIdArray = uniqueId.split("_"); String deviceId = uniqueIdArray[0]; return deviceId; }  static String extractDeviceIdFromUniqueId(String uniqueId); static Long extractLongIdFromUniqueId(String uniqueId); static String generateNextUniqueId(Context context, StudentDao studentDao); static File getStudentDirectory(); static File getTestStudentsDirectory(); static File getStudentImageDirectory(); static File getStudentAvatarDirectory();  }
@Test public void testExtractDeviceIdFromUniqueId() { String uniqueId = "4113947bec18b7ad_1"; String deviceId = StudentHelper.extractDeviceIdFromUniqueId(uniqueId); assertThat(deviceId, is("4113947bec18b7ad")); }