Java 我应该如何测试Servlet过滤器？

在确定如何测试servlet过滤器时遇到困难

@Component
@Order( Ordered.HIGHEST_PRECEDENCE )
class CORSFilter extends OncePerRequestFilter {
    private final Logger log = LoggerFactory.getLogger( CORSFilter.class );

    @Override
    protected void doFilterInternal(
            final HttpServletRequest request,
            final HttpServletResponse response,
            final FilterChain filterChain )
            throws ServletException, IOException {
        log.debug( "request: {}", request );
        response.setHeader( "Access-Control-Allow-Origin", "*" );
        response.setHeader( "Access-Control-Allow-", "POST, GET, PUT, OPTIONS, DELETE" );
        response.setHeader( "Access-Control-Allow-Headers", "content-type, x-auth-token, x-requested-with" );
        response.setHeader( "Access-Control-Expose-Headers", "Location" );
        response.setIntHeader( "Access-Control-Max-Age", 3600 );
        filterChain.doFilter( request, response );
    }
}

以下是我试着写的测试方法

@RunWith( SpringJUnit4ClassRunner.class )
@WebAppConfiguration
@ComponentScan( "com.xenoterracide.rpf.infrastructure.http")
@SpringApplicationConfiguration( classes = { MockServletContext.class } )
public class TestHeaders {

    @Autowired
    private WebApplicationContext context;
    private MockMvc               mockMvc;

    @Before
    public void setup() {
        this.mockMvc = MockMvcBuilders.webAppContextSetup( context ).build();
    }

    @Test
    public void testCORS() throws Exception {
        this.mockMvc.perform( options( "/" ) )
                    .andExpect( status().is2xxSuccessful() )
                    .andExpect( header().string( "Access-Control-Allow-Origin",
                            allOf( notNullValue(), instanceOf( String.class ) ) ) );
    }

}

这是我的测试错误

java.lang.AssertionError: Response header Access-Control-Allow-Origin
Expected: (not null and an instance of java.lang.String)
 but: not null was null

如何测试servlet过滤器是否正常工作？如果测试它们不需要加载完整的上下文、db和all，则会获得额外的分数。

---

这里重要的是mockMvc是手工构建的。如果使用自动配置的mockMvc，测试上下文中所有可用的过滤器都将被添加到其中，在我的例子中，这会在测试spring安全性时导致不良效果。

this.mockMvc = MockMvcBuilders.webAppContextSetup( context )
                              .addFilter(new CORSFilter(), "/*")
                              .build();