### Question:
UserAOHelper { public static String getZoneFromUserPoundZone(final String userName) { if (userName == null || userName.isEmpty()) { throw new IllegalArgumentException("null or empty userName"); } int poundIdx = userName.indexOf("#"); if (poundIdx > -1) { return userName.substring(poundIdx + 1); } else { return ""; } }  static String buildUserSelects(); static void addUserSelectsToBuilder(final IRODSGenQueryBuilder builder); static User buildUserFromResultSet(final IRODSQueryResultRow row,
			final IRODSGenQueryExecutor irodsGenQueryExecutor, final boolean retrieveDN); static String findUserDnIfExists(final String userId, final IRODSGenQueryExecutor irodsGenQueryExecutor); static String getUserNameFromUserPoundZone(final String userName); static String getZoneFromUserPoundZone(final String userName);  }### Answer:
@Test public final void testGetZoneFromUserPoundZoneWithZone() { String user = "testuser"; String zone = "testzone"; String fullUser = user + "#" + zone; String actual = UserAOHelper.getZoneFromUserPoundZone(fullUser); Assert.assertEquals("did not get zone properly", zone, actual); }
@Test public final void testGetZoneFromUserPoundZoneWithNoZone() { String user = "testuser"; String actual = UserAOHelper.getZoneFromUserPoundZone(user); Assert.assertEquals("did not get zone properly", "", actual); }
@Test(expected = IllegalArgumentException.class) public final void testGetZoneFromUserPoundZoneNull() { UserAOHelper.getZoneFromUserPoundZone(null); }
@Test(expected = IllegalArgumentException.class) public final void testGetZoneFromUserPoundZoneBlank() { UserAOHelper.getZoneFromUserPoundZone(""); }