java - 如果MockHttpServletRequestBuilder缓存，则MockMvc.perform会与并行流一起引发ConcurrentModificationException

我正在编写一些Spring集成测试以测试我的应用程序中的Spring Security。我使用RequestPostProcessor创建具有不同权限的测试用户。我也缓存它们以在所有测试中重用。参见下面的代码：

public final class Users {
    public static final RequestPostProcessor
        ANONYMOUS = anonymous();

    public static final RequestPostProcessor
        PERMISSIONS_READ = buildUser(Permissions.PERMISSIONS_READ);
    public static final RequestPostProcessor
        PERMISSIONS_WRITE = buildUser(Permissions.PERMISSIONS_WRITE);
    public static final RequestPostProcessor
        PERMISSIONS_DELETE = buildUser(Permissions.PERMISSIONS_DELETE);

    public static final RequestPostProcessor
        ROLES_READ = buildUser(Permissions.ROLES_READ);
    public static final RequestPostProcessor
        ROLES_WRITE = buildUser(Permissions.ROLES_WRITE);
    public static final RequestPostProcessor
        ROLES_DELETE = buildUser(Permissions.ROLES_DELETE);

    public static final RequestPostProcessor
        USERS_READ = buildUser(Permissions.USERS_READ);
    public static final RequestPostProcessor
        USERS_WRITE = buildUser(Permissions.USERS_WRITE);
    public static final RequestPostProcessor
        USERS_DELETE = buildUser(Permissions.USERS_DELETE);


    private Users() {}

    private static RequestPostProcessor buildUser(Permissions permission) {
        return buildUser(permission.toString(), permission.toString());
    }

    private static RequestPostProcessor buildUser(String name, String... authorities) {
        return user(name).authorities(SecurityUtils.authoritiesFromStrings(authorities));
    }
}

当我在测试中使用它们时，我得到了ConcurrentModificationException。

用法：

....................
@Autowired private WebApplicationContext context;
@Autowired private Filter springSecurityFilterChain;
MockMvc mvc = MockMvcBuilders
        .webAppContextSetup(context)
        .addFilters(springSecurityFilterChain)
        .build();
....................
MockHttpServletRequestBuilder req = get("some-url");
mvc.perform(req.with(Users.ANONYMOUS))
        .andExpect(status().isFound())
        .andExpect(header().string("Location", "login-url"));
Stream.of(Users.PERMISSIONS_WRITE, Users.PERMISSIONS_DELETE,
        Users.ROLES_WRITE, Users.ROLES_DELETE,
        Users.USERS_WRITE, Users.USERS_DELETE)
        .parallel()
        .forEach(Unchecked.consumer(user -> mvc.perform(req.with(user)) //Exception is here and caused by .with(user)
                .andExpect(status().isForbidden())));
....................

例外：

....................
Caused by: java.util.ConcurrentModificationException
at java.util.ArrayList$Itr.checkForComodification(ArrayList.java:901)
at java.util.ArrayList$Itr.next(ArrayList.java:851)
at org.springframework.test.web.servlet.request.MockHttpServletRequestBuilder.postProcessRequest(MockHttpServletRequestBuilder.java:754)
at org.springframework.test.web.servlet.MockMvc.perform(MockMvc.java:145)
at com.ipan.fin.man.integrational.PermissionsTest.lambda$checkReadSecurity$5(PermissionsTest.java:162)//line with my code
....................

在org.springframework.test.web.servlet.request.MockHttpServletRequestBuilder中引发异常，因为我正在对其进行缓存（MockHttpServletRequestBuilder req）并在多个流中使用。因此，以防万一，当一个流在postProcessors上迭代时

@Override
public MockHttpServletRequest postProcessRequest(MockHttpServletRequest request) {
    for (RequestPostProcessor postProcessor : this.postProcessors) { //here
        request = postProcessor.postProcessRequest(request);
        if (request == null) {
            throw new IllegalStateException(
                    "Post-processor [" + postProcessor.getClass().getName() + "] returned null");
        }
    }
    return request;
}

第二个将新的postProcessor添加到postProcessors

@Override
public MockHttpServletRequestBuilder with(RequestPostProcessor postProcessor) {
    Assert.notNull(postProcessor, "postProcessor is required");
    this.postProcessors.add(postProcessor); //here
    return this;
}

ConcurrentModificationException将被抛出。

据我在上面的代码中了解，由于以下两个原因，不允许缓存MockHttpServletRequestBuilder：


它不是线程安全的
MockHttpServletRequestBuilder.with调用将添加新的RequestPostProcessor，而不是像我期望的那样替换旧的。


我对吗？

附言使用顺序流，测试可以正常工作，并且看起来MockHttpServletRequestBuilder.with的调用替换了旧的RequestPostProcessor对象，因为我总是得到正确的测试结果（来自服务器的响应状态）

最佳答案

是的，您的分析是正确的：MockHttpServletRequestBuilder并非设计为可以同时使用。

无论如何，创建MockHttpServletRequest实际上并没有任何明显的开销。

因此，我建议您每次需要时就简单地创建一个新请求，并且使用并行流实际上并不会给您带来很多好处（如果有的话）。

总之，请尽量不要过度设计您的测试。 ;-)

问候，

Sam（Spring TestContext Framework的作者）