如何测试 OkHttp 中的 IOException 情况？

Question

我正在尝试在 OkHttpClient 抛出 IOException 事件中测试我的代码库

待测代码

    try (var response = okHttpClient.newCall(request).execute()) {
        return response;
    } catch (final IOException e) {
        log.error("IO Error from API", e);
        throw new ApiException(e.getMessage(), e);
    }

测试

@Test
void createCustomer_WhenValidRequestAndIOException_ThenThrowAPIException() throws ZeusServiceException, ZeusClientException {

    //Given
    final OkHttpClient okHttpClientMock = mock(OkHttpClient.class, RETURNS_DEEP_STUBS);
    final OkHttpClient.Builder okHttpBuilderMock = mock(OkHttpClient.Builder.class);
    httpClient = new HttpClient(okHttpClientMock, configuration, objectMapper);

    //When
    when(okHttpClientMock.newBuilder()).thenReturn(okHttpBuilderMock);
    when(okHttpBuilderMock.build()).thenReturn(okHttpClientMock);
    when(okHttpClientMock.newCall(any())).thenThrow(IOException.class);
    final var result = httpClient.createCustomer(request);

    assertThatThrownBy(() -> httpClient.createCustomer(request))
        .isInstanceOf(ApiException.class)
        .hasMessage("IO Error from API");
}

我试图模拟OkHttpClientandBuilder类，但是 Builder 是最终的，mockito 无法模拟它。

在被测类的构造函数中，建议您通过调用 this 来创建一个新的 OkHttpClient 实例

        this.okHttpClient = okHttpClient.newBuilder().build();

我尝试围绕 OkHttpClient 创建一个包装器，但这也不起作用

    public class OkHttpClientWrapper extends OkHttpClient {

        private OkHttpClient okHttpClient;

        public OkHttpClientWrapper(final OkHttpClient okHttpClient) {
            this.okHttpClient = okHttpClient;
        }

        @Override
        public OkHttpClient.Builder newBuilder() {
            return new Builder(okHttpClient);
        }
    }
}

如何强制 okhttpclient 抛出 IOException？

Answer 1

最后最好的解决方案是利用 OkHttpMockWebServer

https://github.com/square/okhttp/tree/master/mockwebserver

使用 MockWebserver 意外终止 HTTP 连接的场景会导致 IOException 场景

@Test
void createCustomer_WhenValidRequestAndServerTerminatesConnection_ThenThrowIOException() throws ZeusServiceException, ZeusClientException {

    //Given
    final CreateCustomerRequest request = CreateCustomerRequest.builder().build();

    //When
    mockWebServer.enqueue(new MockResponse()
        .setBody(new Buffer().write(new byte[4096]))
        .setSocketPolicy(SocketPolicy.DISCONNECT_DURING_RESPONSE_BODY));

    assertThatThrownBy(() -> httpClient.createCustomer(request))
        .isInstanceOf(IOException.class)
        .hasMessage("unexpected end of stream");
}

注意：本测试中使用 AssertJ 库