一文带你了解Mock 技术体系

简介

为什么要学习 Mock

提高测试深度
提高测试效率
降低成本

测试股票软件，模拟当天股票全部上涨
测试股票软件，模拟当天股票全部下跌
测试股票软件，模拟部分股票涨幅10%

Test Double 测试替身

Dummy 占位对象对象被传递但从未实际使用过。通常它们仅用于填充参数列表。
Fake 假对象对象实际上有工作实现，但通常采取一些捷径，这使得它们不适合生产（内存数据库就是一个很好的例子）。
Stubs 桩对象为测试期间调用提供预设答案，通常根本不响应任何超出测试程序的内容。
Spies 间谍对象它们还根据调用方式记录一些信息。其中一种形式可能是电子邮件服务，它记录发送了多少消息。
Mocks 模拟对象是我们在这里谈论的：预先编程的对象，这些期望形成了它们期望接收的调用的规范。

测试替身关键概念的区别

一个真实的技术架构例子

dummy 只要端口开着就行
fake 内存数据库
spy UI 界面后端请求记录
stub 假的登录后端服务
hook 新用户判断方法修改
proxy 代理转发机制
mock 模拟对象

Fake 假对象定义

Fake objects actually have working implementations, but usually take some shortcut which makes them not suitable for production (an InMemoryTestDatabase is a good example).

假对象实际上有工作实现，但通常采取一些捷径，这使得它们不适合生产（纯内存数据库就是一个很好的例子）。

Fake 应⽤场景

Stub 桩定义

Stubs provide canned answers to calls made during the test, usually not responding at all to anything outside what's programmed in for the test.

为测试期间调用提供预设答案，通常根本不响应任何超出测试程序的内容。

Stub 应⽤场景 Swagger

Setup Stub Server

java -jar moco-runner-1.2.0-standalone.jar http -p 12345 -c foo.json

{
  "request" :
    {
      "uri" : "/foo",
      "queries" :
        {
          "param" : "blah"
        }
    },
  "response" :
    {
      "text" : "bar"
    }
}

Mock 模拟对象定义

Mocks are pre-programmed with expectations which form a specification of the calls they are expected to receive. They can throw an exception if they receive a call they don't expect and are checked during verification to ensure they got all the calls they were expecting.

模拟预编程了期望，这些期望形成了他们期望接收的调用的规范。如果他们收到了他们不期望的调用，他们可以抛出异常，并在验证过程中进行检查以确保他们得到了他们期望的所有调用。

Mock 两种应用场景

mock on stub：按需返回期望数据
mock on proxy：按需返回真实数据的修改副本

常⽤的 Mock 工具

Charles 测试工程师常用
BurpSuite 黑客常用
Fiddler 只能 Windows 上使用
Nginx 服务器反向代理与修改
Mitmproxy 代理工具可编程
Wiremock 代理工具可编程

mitmproxy

mitmproxy is a set of tools that provide an interactive, SSL/TLS-capable intercepting proxy for HTTP/1, HTTP/2, and WebSockets.

mitmproxy mock on proxy

python3 -m http.server
mitmdump -p 8001  -m reverse:127.0.0.1:8000 --flow-detail 4 -B '/~bs .*Directory.*/Directory/ceshiren.com mock'

mitmproxy 强大的插件机制 Addons

dns
tcp
cert
http/https
websocket

adb mock 案例



import sys

from mitmproxy import ctx
from mitmproxy import tcp
from mitmproxy.utils import strutils
from mitmproxy.tools.main import mitmdump


def tcp_message(flow: tcp.TCPFlow):
    message = flow.messages[-1]
    old_content = message.content
    message.content = old_content.replace(
        b":0;localabstract:webview_devtools_remote_",
        b":   0;localabstract:xweb_devtools_remote_"
    )

    ctx.log.info(
        "[tcp_message{}] from {} to {}:\n{}".format(
            " (modified)" if message.content != old_content else "",
            "client" if message.from_client else "server",
            "server" if message.from_client else "client",
            strutils.bytes_to_escaped_str(message.content))
    )


if __name__ == '__main__':
    sys.argv = ["", "-p", "5038", "--rawtcp", "--mode", "reverse:http://localhost:5037/", "-s", sys.argv[0], "-vv"]
    mitmdump()

WireMock

The flexible tool for building mock APIs.

Create stable development environments, isolate yourself from flakey 3rd parties and simulate APIs that don't exist yet.

wiremock stub

java -jar wiremock-jre8-standalone-2.33.2.jar

{  "request": {    "method": "GET",    "url": "/wiremock"  },
  "response": {    "status": 200,    "body": "Easy!"  }}

mock on stub


@Test
public void exactUrlOnly() {
    stubFor(get(urlEqualTo("/some/thing"))
            .willReturn(aResponse()
                .withHeader("Content-Type", "text/plain")
                .withBody("Hello world!")));

    assertThat(testClient.get("/some/thing").statusCode(), is(200));
    assertThat(testClient.get("/some/thing/else").statusCode(), is(404));
}

mock on proxy


wm.stubFor(get(urlPathEqualTo("/templated"))
  .willReturn(aResponse()
      .proxiedFrom("$!request.headers.X-WM-Proxy-Url")
      .withTransformers("response-template")));


public class ExampleTransformer extends ResponseDefinitionTransformer {


    @Override
    public ResponseDefinition transform(Request request, ResponseDefinition responseDefinition, FileSource files, Parameters parameters) {
        String content=responseDefinition.getTextBody().replace("霍格沃兹", "mock");
        System.out.println(responseDefinition.getTextBody());
        System.out.println(content);
        return new ResponseDefinitionBuilder()
                .withHeader("MyHeader", "Transformed")
                .withStatus(200)
                .withBody(content)
                .build();
    }


    @Override
    public String getName() {
        return "hogwarts_mock";
    }
}