Filter filter = searchRequest.getFilter();
assertTrue( filter instanceof SubstringFilter );
SubstringFilter substringFilter = ( SubstringFilter ) filter;
List<String> initials = substringFilter.getAnySubstrings();
assertEquals( 1, initials.size() );
assertEquals( "kate", initials.get( 0 ) );
assertEquals( "john", substringFilter.getFinalSubstrings() );
}