### Question:
TabDelimitedCertificateFilter extends QwacCertificateFilter { @Override public String getEncodedTppQwacCert(HttpServletRequest httpRequest) { if (httpRequest.getHeader(HEADER_NAME) == null) { return null; } String certificateWithTabs = httpRequest.getHeader(HEADER_NAME); return certificateWithTabs.replaceAll("\t", ""); } TabDelimitedCertificateFilter(
      TppInfoHolder tppInfoHolder,
      RequestProviderService requestProviderService,
      TppErrorMessageBuilder tppErrorMessageBuilder
  ); @Override String getEncodedTppQwacCert(HttpServletRequest httpRequest);  }### Answer:
@Test public void delimitateTabsSuccessful() { HttpServletRequest mock = Mockito.mock(HttpServletRequest.class); Mockito.when(mock.getHeader(Mockito.anyString())).thenReturn("string\twith\ttabs"); String stringWithoutTabs = tabDelimitedCertificateFilter.getEncodedTppQwacCert(mock); assertEquals("stringwithtabs", stringWithoutTabs); }