String addPath(String path) {
        // Make sure the paths always start and end with a slash.
        // This simplifies later comparison with the request path.
        if (!path.startsWith("/")) {
            path = "/" + path;
        }
        if (!path.endsWith("/")) {
            path =  path + "/";
        }
        resourcePrefixes.add(path);

        return path;
    }
@Test
    public void test_addPath() {
        ResourceCacheControl resourceCacheControl = new ResourceCacheControl();

        Assert.assertEquals("/a/b/", resourceCacheControl.addPath("a/b"));
        Assert.assertEquals("/a/b/", resourceCacheControl.addPath("/a/b"));
        Assert.assertEquals("/a/b/", resourceCacheControl.addPath("a/b/"));
        Assert.assertEquals("/a/b/", resourceCacheControl.addPath("/a/b/"));
    }