单元测试 doFilter 的相关性 ID

Question

我正在使用 dropwizard 构建应用程序。

我做了一个过滤器来拦截和记录调用服务的相关 ID。

如果传入请求的标头中没有标头“Correlation-Id”，我们将在响应中附加一个标头。

以下是过滤器：

public class CorrelationIdServletFilter implements Filter {

private static final Logger LOGGER =

  LoggerFactory.getLogger(CorrelationIdServletFilter.class);

 private static final String CORRELATION_ID_HEADER_NAME = "Correlation-ID";

 private static final String CORRELATION_ID_MDC_KEY = " ";

 private static final InheritableThreadLocal<String> correlationId =

  new InheritableThreadLocal<>();

  public static String getCorrelationId() {

return correlationId.get();

 }

 @Override

 public void init(FilterConfig filterConfig) throws ServletException {}

 @Override

  public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)

  throws IOException, ServletException {

try {

  HttpServletRequest req = (HttpServletRequest) request;

  HttpServletResponse res = (HttpServletResponse) response;

  String correlationIdHeaderValue = req.getHeader(CORRELATION_ID_HEADER_NAME);

  LOGGER.debug

      (

      "HTTP Header("

          + CORRELATION_ID_HEADER_NAME

          + ") = ["

          + correlationIdHeaderValue

          + "] will generate a new correlationId if incoming is NULL");

  String correlationIdRaw;

  if (!StringUtils.isEmpty(correlationIdHeaderValue)) {

    correlationIdRaw = correlationIdHeaderValue;

  } else {

    correlationIdRaw = UUID.randomUUID().toString();

  }

  LOGGER.debug("Request: (" + req.getRequestURI() + ") is marked as :" + correlationIdRaw);

  correlationId.set(correlationIdRaw);

  MDC.put(CORRELATION_ID_MDC_KEY, getCorrelationId());

  res.addHeader(CORRELATION_ID_HEADER_NAME, correlationIdRaw);

  LOGGER.debug(

      "Response holds correlationId : ("

          + res.getHeader("Correlation-ID")

          + ") in its header ");

  chain.doFilter(req, res);

} finally {

  correlationId.remove();

  MDC.remove(CORRELATION_ID_MDC_KEY);

}

}

  @Override

  public void destroy() {}

}

我需要编写单元测试来涵盖两种情况：

1. 发送请求时没有关联 ID。检查在服务器端生成的 id。

2. 当发送带有相关 ID 的响应时。检查它是否与响应一起发回。

谁能指出我如何做到这一点？

Answer 1

您编写的测试的一些主要问题：被测类永远不会被嘲笑（可能有一些例外），因为您想对被测类的各种方法进行单元测试的实际调用。我们应该始终为被测类的不同方法编写单独的单元测试。在这里，我可以看到您还调用了init和destroy方法，而当您要测试该doFilter方法时不需要这些方法。当我们创建任何模拟对象时，我们使用期望来定义我们期望对模拟对象进行的调用，并在需要时让它们返回一些存根值。现在，我已经尝试编写正确的测试来断言您要测试的两种情况：@Testpublic void testResponse_for_RequestWithoutCcid() throws IOException, ServletException {HttpServletRequest httpServletRequest = mock(HttpServletRequest.class);HttpServletResponse httpServletResponse = mock(HttpServletResponse.class);FilterChain filterChain = mock(FilterChain.class);CorrelationIdServletFilter correlationIdServletFilter = new CorrelationIdServletFilter();expect(httpServletRequest.getHeader(CORRELATION_ID_HEADER_NAME)).andReturn(""); // Empty correlation id in the requestCapture capturedCorrelationIdRaw = newCapture();httpServletResponse.addHeader(CORRELATION_ID_HEADER_NAME, capture(capturedCorrelationIdRaw));expectLastCall(); // used for void methods in EasyMock frameworkfilterChain.doFilter(httpServletRequest, httpServletResponse);expectLastCall();CorrelationIdServletFilter.doFilter(httpServletRequest, httpServletResponse,&nbsp; &nbsp; filterChain);assertNotEmpty(capturedCorrelationIdRaw.getValue());verify(httpServletRequest, times(1))&nbsp; &nbsp; .getHeader(CORRELATION_ID_HEADER_NAME);verify(httpServletResponse, times(1))&nbsp; &nbsp; .addHeader(CORRELATION_ID_HEADER_NAME, anyString);}该测试需要根据所使用的实际测试框架进行更新，但我已尽力让您了解测试应该是什么样子。