### Question:
OtpService { public String getAuthenticationFromUiExtensionToken(final String token) throws OtpAuthenticationException { return getAuthenticationFromToken(uiExtensionCache.asMap(), token); } OtpService();  OtpService(final int duration, final TimeUnit units); String generateDownloadToken(final OtpAuthenticationToken authenticationToken); String getAuthenticationFromDownloadToken(final String token); String generateUiExtensionToken(final OtpAuthenticationToken authenticationToken); String getAuthenticationFromUiExtensionToken(final String token);  }### Answer:
@Test(expected = OtpAuthenticationException.class) public void testGetNonExistentUiExtensionToken() throws Exception { otpService.getAuthenticationFromUiExtensionToken("Not a real ui extension token"); }