如何在测试中模拟StreamingResponseBody？

Question

在我的生产代码中，我需要对响应StreamingResponseBody.的控制器执行POST命令这类守则的一个简短例子是：

@RestController
@RequestMapping("/api")
public class DalaLakeRealController {

    @PostMapping(value = "/downloaddbcsv", produces = MediaType.APPLICATION_JSON_VALUE)
    public ResponseEntity<StreamingResponseBody> downloadDBcsv(@Valid @RequestBody SearchQuery searchRequest) {
        return ResponseEntity.ok()
                .header(HttpHeaders.CONTENT_TYPE, "application/csv")
                .header(HttpHeaders.CONTENT_DISPOSITION, "attachment;filename=demoStream.csv")
                .body(
                        get3Lines()
                );
    }

    public StreamingResponseBody get3Lines() {
        StreamingResponseBody streamingResponseBody = new StreamingResponseBody() {
            @Override
            public void writeTo(OutputStream outputStream) throws IOException {
                outputStream.write("LineNumber111111111\n".getBytes());
                outputStream.write("LineNumber222222222\n".getBytes());
                outputStream.write("LineNumber333333333\n".getBytes());
            }
        };
        return streamingResponseBody;
    }
}

在测试中，我想模拟这个控制器的响应。我阅读了以下链接:模拟外部控制器的使用MockRestServiceServer测试REST客户端。

但是，在ClientHttpResponse of mockServer一书中，它预计会出现andRespond或ResponseCreator。

mockServer.expect(once(), requestTo("http://localhost:8080/api/downloaddbcsv"))
    .andRespond(withSuccess("{message : 'under construction'}", MediaType.APPLICATION_JSON));

如何使用StreamingResponseBody在MockRestServiceServer中响应？

Answer 1

我希望这能指引你..。

@Test
public void whenTopicNotExistsThenTopicNotFound() throws IOException, NakadiException {
    when(eventTypeRepository.findByName(TEST_EVENT_TYPE_NAME)).thenThrow(NoSuchEventTypeException.class);

    final StreamingResponseBody responseBody = createStreamingResponseBody();

    final Problem expectedProblem = Problem.valueOf(NOT_FOUND, "topic not found");
    assertThat(responseToString(responseBody), TestUtils.JSON_TEST_HELPER.matchesObject(expectedProblem));
}

从：https://www.programcreek.com/java-api-examples/index.php?api=org.springframework.web.servlet.mvc.method.annotation.StreamingResponseBody获得上述代码

其想法是将StreamingResponseBody转换为String。然后你就可以做这样的事情：

mockServer.expect(once(), requestTo("http://localhost:8080/api/downloaddbcsv"))
.andRespond(withSuccess(responseToString(responseBody), MediaType.APPLICATION_JSON));

此外，在这里看一看：https://github.com/spring-projects/spring-framework/blob/master/spring-webmvc/src/test/java/org/springframework/web/servlet/mvc/method/annotation/StreamingResponseBodyReturnValueHandlerTests.java

streamingResponseBody()和responseEntity()测试方法将响应转换为String。

Answer 2

虽然这篇文章已经过时了，但这个答案可能会帮助现在的人。

这个问题的答案是功能接口( Functional，streamingResponseBody)，如下面的代码所示，再加上cloudStorageService中下载的模拟返回。

    @Test
    @WithUserDetailsMock(
        email = "participant@localhost",
        authorities = AuthoritiesConstants.USER,
        cashflowAuthorities = CashflowAuthoritiesConstants.PARTICIPANT
    )
    void testDownloadFileThenSuccess() throws Exception {
        Member loggedMember = memberService.getLoggedMember();
        File file = EntityBuilder.file(loggedMember.getGroup()).build(fileRepository::save);
        SubmittedPayment submittedPayment = EntityBuilder
            .submittedPayment(loggedMember)
            .with(SubmittedPayment::setFile, file)
            .build(submittedPaymentRepository::save);

        String endpoint = String.format("/api/payment/submit/%d/file", submittedPayment.getId());
        byte[] fileBytes = "some content".getBytes();
        StreamingResponseBody streamingResponseBody = objectStream -> {
            var mockInputStream = new ByteArrayInputStream(fileBytes);
            try (mockInputStream) {
                byte[] bytes = mockInputStream.readAllBytes();
                objectStream.write(bytes, 0, bytes.length);
            }
        };
        doReturn(streamingResponseBody).when(cloudStorageService).download(fileArgumentCaptor.capture());

        MvcResult response = restTransactionMockMvc.perform(get(endpoint)).andExpect(status().isOk()).andReturn();

        assertThat(file).isEqualTo(fileArgumentCaptor.getValue());
        assertThat(Arrays.equals(fileBytes, response.getResponse().getContentAsByteArray())).isTrue();
    }