@Test
    public void test_doFilter_withNullWebApiManager() throws IOException, ServletException {
        // Setup mock objects
        HttpServletRequest request = createMockHttpServletRequest();
        HttpServletResponse response = createMockHttpServletResponse();
        AtomicBoolean chainCalled = new AtomicBoolean(false);

        FilterChain chain = new FilterChain() {
            @Override