Unit testing a jee filter - testing

Question

I am trying to test this filter:
public class HttpMethodOverrideHeaderFilter extends OncePerRequestFilter {
private static final String X_HTTP_METHOD_OVERRIDE_HEADER = "X-HTTP-Method-Override";
#Override
protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain)
throws ServletException, IOException {
if (isMethodOverriden(request)) {
HttpServletRequest wrapper = new HttpMethodRequestWrapper(request, request.getHeader(X_HTTP_METHOD_OVERRIDE_HEADER).toUpperCase(Locale.ENGLISH));
filterChain.doFilter(wrapper, response);
}
else {
filterChain.doFilter(request, response);
}
}
private boolean isMethodOverriden(HttpServletRequest request) {
String methodOverride = request.getHeader(X_HTTP_METHOD_OVERRIDE_HEADER);
return RequestMethod.POST.name().equalsIgnoreCase(request.getMethod()) &&
(RequestMethod.PUT.name().equalsIgnoreCase(methodOverride) || RequestMethod.DELETE.name().equalsIgnoreCase(methodOverride));
}
protected static class HttpMethodRequestWrapper extends HttpServletRequestWrapper {
private final String method;
public HttpMethodRequestWrapper(HttpServletRequest request, String method) {
super(request);
this.method = method;
}
#Override
public String getMethod() {
return this.method;
}
}
}
And this is the unit test:
#RunWith(MockitoJUnitRunner.class)
public class HttpMethodOverrideHeaderFilterTest {
private static final String X_HTTP_METHOD_OVERRIDE_HEADER = "X-HTTP-Method-Override";
private HttpMethodOverrideHeaderFilter httpMethodOverrideHeaderFilter;
#Mock
private HttpServletRequest httpServletRequest;
#Mock
private HttpServletResponse httpServletResponse;
#Mock
private FilterChain filterChain;
#Before
public void setUp() {
httpMethodOverrideHeaderFilter = new HttpMethodOverrideHeaderFilter();
}
#Test
public void testDoFilterInternalWithPUTMethodAsOverrideHeader() throws Exception {
when(httpServletRequest.getHeader(X_HTTP_METHOD_OVERRIDE_HEADER)).thenReturn("PUT");
when(httpServletRequest.getMethod()).thenReturn("POST");
HttpServletRequest wrapper = new HttpMethodOverrideHeaderFilter.HttpMethodRequestWrapper(httpServletRequest, "PUT");
httpMethodOverrideHeaderFilter.doFilterInternal(httpServletRequest, httpServletResponse, filterChain);
verify(filterChain).doFilter(wrapper, httpServletResponse);
}
}
The test is not passing as wrapper is not the same instance. Basically what I need to know is if the wrapper was set the PUT method. Any ideas?

Answer 1

I found a way to do it:
#Test
public void testDoFilterInternalWithPUTMethodAsOverrideHeader() throws Exception {
when(httpServletRequest.getHeader(X_HTTP_METHOD_OVERRIDE_HEADER)).thenReturn("PUT");
when(httpServletRequest.getMethod()).thenReturn("POST");
httpMethodOverrideHeaderFilter.doFilterInternal(httpServletRequest, httpServletResponse, filterChain);
ArgumentCaptor<ServletRequest> requestCaptor = ArgumentCaptor.forClass(ServletRequest.class);
ArgumentCaptor<ServletResponse> responseCaptor = ArgumentCaptor.forClass(ServletResponse.class);
verify(filterChain).doFilter(requestCaptor.capture(), responseCaptor.capture());
HttpMethodOverrideHeaderFilter.HttpMethodRequestWrapper wrapper = (HttpMethodOverrideHeaderFilter.HttpMethodRequestWrapper) requestCaptor.getValue();
assertEquals(wrapper.getMethod(), "PUT");
}
if anyone know any better way, let me know!!!