如何用Headers模拟HttpServlet请求

Question

我使用Mockito和JUnit来测试应用程序。我需要在嘲笑时向HttpServletRequest添加标题。这是我第一次使用mock概念来测试应用程序。在使用这个mock概念的同时，我们如何设置请求对象的头？

应用程序代码

@Produces({ MediaType.APPLICATION_JSON })
@Path("/devices")
public class DvrRestService {
    private static final Logger logger = LoggerFactory.getLogger(DvrRestService.class);
    private DvrMiddleService dvrMiddleService;
    @Inject
    public DvrRestService(DvrMiddleService dvrMiddleService) {
        this.dvrMiddleService = dvrMiddleService;
    }
    @GET 
    @Path("/{deviceId}/metadata")
    public Response getDeviceMetadata(@Context HttpServletRequest request, @PathParam("deviceId") String deviceId,
        @RequiredSession final Session session) {
        try {
            public static String[] REQUEST_HEADERS = { "if-none-match" };
            List<String> requiredHeaders = Lists.newArrayList(REQUEST_HEADERS);
            Map<String, String> headers = new HashMap<String, String>();
            Enumeration<String> headerNames = request.getHeaderNames();
            while (headerNames.hasMoreElements()) { // here gettting NullPointerException
                String headerName = headerNames.nextElement();
                if (requiredHeaders.contains(headerName.toLowerCase())) {
                    String value = request.getHeader(headerName);
                    if (value != null) {
                        headers.put(headerName, value);
                        System.out.println("headerName: " + headerName + ", Value: " + value);
                    }
                }
            }
            DvrResponse response = dvrMiddleService.getDeviceMetadata(deviceId.toUpperCase(), getHeaders(request));
            return processResponse(response.statusCode, response.getResponse(), DeviceMetadataResponse.class,
                response.getHeaders());
        } catch (Exception e) {
            return processErrorResponse(e, new DeviceMetadataResponse(), logger);
        }
    }
}

测试

public class DvrRestServiceTest {
    static DvrMiddleService dms;
    static HttpServletRequest request;
    static Session session;
    static DvrRestService drs;
    public static final String DeviceId = "000004D42070";
    @BeforeClass
    public static void init(){
        dms = mock(DvrMiddleService.class);
        request = mock(HttpServletRequest.class);
        session = mock(Session.class);
        drs = new DvrRestService(dms);
    }
    @Test
    public void getDeviceMetadataTest(){
        Response rs = drs.getDeviceMetadata(request, DeviceId, session);
        assertEquals(Response.Status.OK, rs.getStatus());
    }
}

Answer 1

作为主体的起点和演示，您可以从以下片段开始。

// define the headers you want to be returned
Map<String, String> headers = new HashMap<>();
headers.put(null, "HTTP/1.1 200 OK");
headers.put("Content-Type", "text/html");
// create an Enumeration over the header keys
Enumeration<String> headerNames = Collections.enumeration(headers.keySet());
// mock HttpServletRequest
HttpServletRequest request = mock(HttpServletRequest.class);
// mock the returned value of request.getHeaderNames()
when(request.getHeaderNames()).thenReturn(headerNames);
System.out.println("demonstrate output of request.getHeaderNames()");
while (headerNames.hasMoreElements()) {
    System.out.println("header name: " + headerNames.nextElement());
}
    
// mock the returned value of request.getHeader(String name)
doAnswer(new Answer<String>() {
    @Override
    public String answer(InvocationOnMock invocation) throws Throwable {
        Object[] args = invocation.getArguments();
        return headers.get((String) args[0]);
    }
}).when(request).getHeader("Content-Type");
System.out.println("demonstrate output of request.getHeader(String name)");
String headerName = "Content-Type";
System.out.printf("header name: [%s]   value: [%s]%n", 
        headerName, request.getHeader(headerName));
}

输出

demonstrate output of request.getHeaderNames()
header name: null
header name: Content-Type
demonstrate output of request.getHeader(String name)
header name: [Content-Type]   value: [text/html]

Answer 2

对于HttpServletRequest，我建议使用功能齐全的mock类型，而不是直接用Mockito mock来嘲笑它。spring-test库具有用于此目的的MockHttpServletRequest：

@BeforeClass
public static void init(){
    // ...
    MockHttpServletRequest mockRequest = new MockHttpServletRequest();
    mockRequest.addHeader("Content-Type", "text/html");
    mockRequest.addHeader("if-none-match", "*");
    mockRequest.addHeader("customHeader", "customValue");
    this.request = mockRequest;
}

基本原理

HttpServletRequest是一个有20多种方法的复杂接口，它们之间有明确的相互作用。从库中为HttpServletRequest使用一个功能齐全的mock类型可以简化mock，从而无需仔细地对所使用的方法进行mock。

这种方法的一个优点是，面对未来使用类上的其他方法获得相同信息的重构，它更有弹性。在检索"；如果没有匹配"0"；在HttpServletRequest中，我看到三种不同的方法可以合法地用于检索标头：getHeader(String name)、getHeaders(String name)和getHeaderNames()。此外，getHeader和getHeaders的自变量不区分大小写（对于"ifnonematch"、"ifNonematch"等返回相同的结果），因此任何可能的自变量大小写都是正确的。通过直接mock支持这一点是非常可能的，尽管它涉及额外的样板代码，这会使测试变得复杂，并使其不那么明显。

spring-test库中的MockHttpServletRequest类模拟此接口，并允许通过简单的API设置头和其他值。虽然该库是为测试Spring应用程序而设计的，但MockHttpServletRequest类独立于任何Spring特定的功能，即使应用程序不使用Spring，也应该完全可以单独使用。

Answer 3

这在我的案例中起到了作用

mockMvc.perform(post("<<url>>").content("<<jsonStrig>>").header("key", "value"));

也可以用于get请求。

Answer 4

我知道OP正在使用Mockito。这个答案适用于那些使用spock的人。你可以很容易地做到这一点。

class MyTestSpec extends Specification {
    HttpServletRequest request = Mock()
    MyTestClass myTestClass = new MyTestClass()
    def 'my test'() {
        setup:
        String expectedHeader = "x-mycustom-header"
        when:
        String someResult = myTestClass.someTestMethod()
        then:
        // here is where you return your header from the mocked request
        1 * request.getHeader(_ as String) >> expectedHeader
    }
}