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。此类代码的简短示例是：

@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，我想模拟来自此控制器的响应。我已阅读以下链接：Using MockRestServiceServer to Test a REST Client模拟外部控制器。 但是在mockServer的andRespond中，它期望ClientHttpResponse或ResponseCreator

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

我如何在MockRestServiceServer中使用StreamingResponseBody进行响应？

Answer 1

我希望这会指导您...

@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处获得了上面的代码

想法是将StreamingResponseBody转换为String。然后，您可以执行以下操作：

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

此外，在这里看看：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a String。