如何使用RestTemplate脱机进行单元测试？

Question

我有一个直接依赖于RestTemplate的类.我希望我有离线的JUnit测试.

我怎么能在我的单元测试中模拟RestTemplate？

Answer 1

Sping 3.0推出RestTemplate.从版本3.2开始,Spring MVC测试框架MockRestServiceServer为单元测试客户端REST代码提供了类.

Answer 2

我建议重构你的客户端代码以删除直接依赖RestTemplate,并将其替换为引用RestOperations,这是由实现的接口RestTemplate.以及你应该编码的那个.

然后,您可以RestOperations在代码中注入存根或模拟以进行单元测试,并RestTemplate在实际使用时注入.

Answer 3

您可以在包中使用Mock类org.springframework.mock.web.

通常你需要MockHttpServletRequest和MockHttpServletResponse,但如果你需要更多的控制,你可能还需要其他人,例如MockRequestDispatcher.

这两者都实现了相应的Servlet接口,但是为测试添加了便利方法(最重要的是:它们在没有真正的HTTP连接的情况下工作).

您可以在弹簧测试罐中找到模拟类(可通过Maven访问)

更新:看来上面的课程RestTemplate毕竟没什么大不了的.你需要的是创建一个模拟器ClientHttpRequestFactory,我很惊讶地看到上面的包中没有一个.这里有一些代码可以帮助您入门(尚未测试过):

public class MockClientHttpRequestFactory implements
    ClientHttpRequestFactory{

    // overwrite this if you want
    protected MockClientHttpResponse createResponse(){
        return new MockClientHttpResponse();
    }

    // or this
    protected HttpStatus getHttpStatusCode(){
        return HttpStatus.OK;
    }

    // or even this
    @Override
    public ClientHttpRequest createRequest(final URI uri,
        final HttpMethod httpMethod) throws IOException{
        return new MockClientHttpRequest(uri, httpMethod);
    }

    public class MockClientHttpResponse implements ClientHttpResponse{
        private final byte[] data = new byte[10000];
        private final InputStream body = new ByteArrayInputStream(data);
        private final HttpHeaders headers = new HttpHeaders();
        private HttpStatus status;

        @Override
        public InputStream getBody() throws IOException{
            return body;
        }

        @Override
        public HttpHeaders getHeaders(){
            return headers;
        }

        @Override
        public HttpStatus getStatusCode() throws IOException{
            return getHttpStatusCode();
        }

        @Override
        public String getStatusText() throws IOException{
            return status.name();
        }

        @Override
        public void close(){
            try{
                body.close();
            } catch(final IOException e){
                throw new IllegalStateException(e);
            }

        }

    }

    class MockClientHttpRequest implements ClientHttpRequest{

        private final HttpHeaders headers = new HttpHeaders();
        private final HttpMethod method;
        private final URI uri;
        private final OutputStream body = new ByteArrayOutputStream();

        MockClientHttpRequest(final URI uri, final HttpMethod httpMethod){
            this.uri = uri;
            method = httpMethod;

        }

        @Override
        public OutputStream getBody() throws IOException{
            return body;
        }

        @Override
        public HttpHeaders getHeaders(){
            return headers;
        }

        @Override
        public HttpMethod getMethod(){
            return method;
        }

        @Override
        public URI getURI(){
            return uri;
        }

        @Override
        public ClientHttpResponse execute() throws IOException{
            return createResponse();
        }

    }


}