如何在HTTP响应中进行单元测试“缓存控制”-Spring MVC Application

Question

I have the following filter to clear cache:

public class CacheControlFilter implements Filter {

    @Override
    public void doFilter(ServletRequest request, ServletResponse response,
            FilterChain chain) throws IOException, ServletException {

        logger.info("doFilter method called clearing cache");

        HttpServletResponse resp = (HttpServletResponse) response;
        resp.setDateHeader("Expires", 0);
        resp.setHeader("Last-Modified", new Date().toString());
        resp.setHeader("Cache-Control", "no-store, no-cache, must-revalidate, max-age=0, post-check=0, pre-check=0");
        resp.setHeader("Pragma", "no-cache");

        chain.doFilter(request, response);
    }
}

I want to carry out a unit test to test if the Cache-Control is being set to no-cache when the above code is executed.

Basically I wanted to add some dummy value in the Cache-Control response header and execute my unit test to check if it is being set to no-cache for example.

I am using mockito and thats my starting point to carry out the test but i don't know how to set a dummy value Cache-Control to the response as shown below:

public class CacheControlFilterTest {

    @InjectMocks CacheControlFilter cacheControlFilter;
    @Mock ServletRequest request;
    @Mock HttpServletResponse response ;
    @Mock FilterChain filterChain;

    public CacheControlFilterTest() {}

    @Test
    public void doFilterTest() throws IOException, ServletException {
        cacheControlFilter.doFilter(request, response, filterChain);
    }
}

Any advice is most welcome.

Answer 1

First off, you should add the Mockito Runner , if you're using JUnit:

@RunWith(MockitoJUnitRunner.class)
public class CacheControlFilterTest { ... }

Basically I wanted to add some dummy value in the Cache-Control response header and execute my unit test to check if it is being set to no-cache for example.

In order to do that, i would personally prefer to use spring's mock implementations of HttpServletRequest and HttpServletResponse , which are MockHttpServletRequest and MockHttpServletResponse , respectively. So, your CacheControlFilterTest would be something like following so far:

@RunWith(MockitoJUnitRunner.class)
public class CacheControlFilterTest {
    @InjectMocks CacheControlFilter cacheControlFilter;
    @Spy MockHttpServletRequest request;
    @Spy MockHttpServletResponse response;
    @Mock FilterChain filterChain;

    // The rest will be roll out very soon!
}

Then you can user those mock implementations in your test, something like:

@Test
public void doFilterTest() throws IOException, ServletException {
    final String CACHE_CONTROL_VALUE = "no-store, no-cache, must-revalidate, max-age=0, post-check=0, pre-check=0";
    response.setHeader("Cache-Control", "some value");

    cacheControlFilter.doFilter(request, response, filterChain);

    assertEquals(response.getHeader("Cache-Control"), CACHE_CONTROL_VALUE);
}