public void testCorsHeadersPreflight() throws IOException, ServletException {
MockHttpServletRequest request = new MockHttpServletRequest();
request.addHeader(HttpHeaders.AUTHORIZATION, "bearer dummy-access-token");
request.addHeader("Origin", "http://www.test.org");
request.addHeader("Access-Control-Request-Method", "PATCH");
request.addHeader("Access-Control-Request-Headers", HttpHeaders.AUTHORIZATION + ", X-Custom-Header");
request.setMethod("OPTIONS");
MockHttpServletResponse response = new MockHttpServletResponse();
//null FilterChain as chain.filter to proceed the flow is not called with preflight
filter.doFilter(request, response, null);