如何使用标头模拟 HttpServletRequest？

java junit servlets mockito

2022-09-02 09:39:28

我正在使用Mockito和JUnit来测试应用程序。我需要在嘲笑时将标头添加到HttpServletRequest中。这是我第一次使用模拟概念来测试应用程序。在使用此模拟概念时，我们如何将标头设置为请求对象？

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());
    }
}

答案 1

作为主体的起点和演示，可以从以下代码段开始。

// 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]

答案 2

对于HttpServletRequest，我建议使用功能齐全的模拟类型，而不是直接用Mockito模拟来模拟它。Spring-test库有MockHttpServletRequest用于此目的：

@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;
}

理由

HttpServletRequest是一个复杂的接口，有20多个方法，它们之间有明确的相互作用。使用函数齐全的 mock 类型 for from 可简化模拟，无需仔细模拟正在使用的方法。HttpServletRequest

这种方法的一个优点是，面对将来使用类上的其他方法获取相同信息的重构，它具有更强的弹性。在检索中的 “if-none-match” 标头时，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，两者的参数都是不区分大小写的（对于“if-none-match”，“If-None-Match”等，将返回相同的结果），因此任何可能的参数大小写都是正确的。非常有可能通过直接模拟来支持这一点，尽管它涉及额外的样板代码，使测试复杂化并使其不那么明显。HttpServletRequestgetHeadergetHeaders

来自弹簧测试库中的 MockHttpServletRequest 类模拟了这个接口，并允许通过一个简单的 API 设置标头和其他值。虽然该库是为测试Spring应用程序而设计的，但该类独立于任何Spring特定的功能，即使应用程序不使用Spring，它也应该完全可用。MockHttpServletRequest