接口测试 - 用Postman进行Apitest

Posted 2021-04-24 吾优测试

一、Pre Request Scripts

Postman v0.10+ 版本支持pre-request scripts。

prerequest script.png

pre-request scripts是一个关联了收藏夹内request，并且在发送request之前执行的代码片段。这对于在request header中包含时间戳或者在URL参数中发送一个随机字符串都是非常有用的。

例如：如果要在request的header中包含一个时间戳，你可以设置一个环境变量由一个函数返回他的值。

postman.setEnvironmentVariable('timestampHeader',new Date());

你可以在header中使 timestampHeader 变量，当request发送的时候，你的pre-request script将被执行，这个timestampHeader 变量的值将会替换{{timestampHeader}}。

注意：我们设置的环境对使用的环境变量必须是有效的。

二、Writing Tests

1.基本结构

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![Uploading prerequest script_871640.png . . .]

Basic structure.png

Postman给了你一个环境让你能够为每个request编写、执行你的test，而不用担心任何额外的设置。

一个Postman的test本质上是javascript的代码可以用来为一些特殊的test设置值。你可以在对象中设置一个描述性的键作为一个元素，然后声明他如果是true或false。

tests[“Body contains user_id”] = responseBody.has(“user_id”)

这回核对body中是否包含了user_id这个字符串。如果你需要，你可以增加更多的键，这取决于你要用test做多少的事情。

test被保存为收藏夹request的一部分，这对于后端或前端的工程师来确保API运行的正常都是非常有意义的。

2.SNIPPETS

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在写test的时候这里有些事情需要注意，Postman尝试使得列出常用的片段更简单。你可以选择你想添加的片段，然后适当的代码将被添加到test的编辑器中。这是一个很好的方法来快速的构建test

3.查看结果

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view result.png

Postman在你执行一个request的时候执行test，当然你可以选择不考虑test。结果被显示在一个tab里，并在头部显示多少test通过了测试。你设置在test中的变量将会被列在这里。如果值是true，这个test就会通过。你可以保持test tab活动直到你确保所有的test执行完。

三、Testing Sandbox

Postman的sandbox是一个JavaScript的执行环境，这使得你能够为request写pre-request scripts和test scripts 。不论你写的代码是pre-request scripts还是test script都会在sandbox中执行。

1.常用的库和工具

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• Lodash：
  JS utility library

• jQuery (Deprecated):
  Cross-platform JavaScript library. This will be removed in future versions of the sandbox.

• BackboneJS (Deprecated):
  Provides simple models, views, and collections. This will be removed in future versions of the sandbox.

• SugarJS:
  Extends native JS objects with useful methods

• tv4 JSON schema validator:
  Validates JSON objects against v4 of the json-schema draft

• CryptoJS:
  standard and secure cryptographic algorithms. Supported algorithms: AES, DES, EvpKDF, HMAC-MD5, HMAC-SHA1/3/256/512, MD5, PBKDF2, Rabbit, SHA1/3/224/256/512, TripleDES

• xml2Json(xmlString):
  This function behaves the same in Newman and Postman

• xmlToJson(xmlString)(Deprecated):
  This function does NOT behave the same in Newman and Postman

• postman.getResponseHeader(headerName) (Test-only):
  returns the response header with name "headerName", if it exists. Returns null if no such header exists. Note: According to W3C specifications, header names are case-insensitive. This method takes care of this.
  postman.getResponseHeader("Content-type") and postman.getResponseHeader("content-Type") will return the same value.

2.环境和全局变量

• postman.setEnvironmentVariable(variableName, variableValue) : Sets an environment variable "variableName", and assigns the string "variableValue" to it. You must have an environment selected for this method to work. Note: Only strings can be stored. Storing other types of data will result in unexpected behavior.

• postman.setGlobalVariable(variableName, variableValue):
  Sets a global variable "variableName", and assigns the string "variableValue" to it. Note: Only strings can be stored. Storing other types of data will result in unexpected behavior.

• postman.clearEnvironmentVariable(variableName):
  Clears the environment variable named "variableName". You must have an environment selected for this method to work.

• postman.clearGlobalVariable(variableName):
  Clears the global variable named "variableName".

• postman.clearEnvironmentVariables():
  Clears all environment variables. You must have an environment selected for this method to work.

• postman.clearGlobalVariables():
  Clears all global variables.

• environment:
  A dictionary of variables in the current environment. Use environment["foo"]
  to access the value of the "foo" environment variable.

• globals:
  A dictionary of global variables. Useglobals["bar"]
  to access the value of the "bar" global variable.

3.动态变量

Postman也有一些动态变量，你可以用在你的request中。这个现在主要还是在实现阶段，更多的功能以后被被添加进来。注意：动态变量不可以用于SandBox中，你只能在request的URL、headers、body中以放在双花括号中间的形式使用。

• {{$guid}}: Adds a v4 style guid

• {{$timestamp}}: Adds the current timestamp.

• {{$randomInt}}: Adds a random integer between 0 and 1000

4. Cookies

+ responseCookies {array} （Postman-only）:
Gets all cookies set for the domain. You will need to enable the Interceptor for this to work.

• postman.getResponseCookie(cookieName)（Postman-only）:
  Gets the response cookie with the given name. You will need to enable the interceptor for this to work. Check out the blog post.

5.Request/response相关属性

• request {object}:
  Postman makes the request object available to you while writing scripts. This object is read-only. Changing properties of this object will have no effect. Note: Variables will NOT be resolved in the request object. The request object is composed of the following:

• data {object}:
  this is a dictionary of form data for the request. (request.data["key"]=="value")

• headers {object}:
  this is a dictionary of headers for the request (request.headers["key"]=="value")

• method {string}:
  GET/POST/PUT etc.

• url {string}:
  the url for the request.

• responseHeaders {object}(Test-only)(Deprecated):
  This is a map of the response headers. This is case-sensitive, and should not be used. Check thepostman.getResponseHeader()
  method listed above.

• responseBody {string}(Test-only):
  A string containing the raw response body text. You can use this as an input to JSON.parse, or xml2Json.

• responseTime {number}(Test-only):
  The response time in milliseconds

• responseCode {object}(Test-only):
  Contains three properties:

• code {number}:
  The response code (200 for OK, 404 for Not Found etc)

• name {string}:
  The status code text

• detail {string}:
  An explanation of the response code

• tests {object}(Test-only):
  This object is for you to populate. Postman will treat each property of this object as a boolean test.

• iteration {number}:
  Only available in the Collection Runner and Newman. Represents the current test run index. Starts from 0.

(Test-only): This object is only available in the test script section. Using this in a pre-request script will throw an error.

四、Testing 实例

我们来看一些Postman用于test的例子。这些例子中的大多数在Postman中是有效的，他们像一行JavaScript语句一样简答。在你的request中你可以有很多的test。

注意：test脚本在从服务器收到response后执行

1.设置环境变量：

postman.setEnvironmentVariable("key", "value");

2.设置全局变量：

 postman.setGlobalVariable("key", "value");

3.检查response的body中是否包含字符串：

tests["Body matches string"] = responseBody.has("string_you_want_to_search");

4.把XML的body转换成JSON对象：

var jsonObject = xml2Json(responseBody);

5.检查response的body是都为一个字符串：

tests["Body is correct"] = responseBody === "response_body_string";

6.检查JSON的值：

var data = JSON.parse(responseBody);
tests["Your test name"] = data.value === 100;

7.内容类型存在（检查不区分大小写）

tests["Content-Type is present"] = postman.getResponseHeader("Content-Type"); //Note: the getResponseHeader() method returns the header value, if it exists.

8.内容类型存在（区分大小写）：

tests["Content-Type is present"] = responseHeaders.hasOwnProperty("Content-Type");

9.response的响应时间小于200ms：

tests["Response time is less than 200ms"] = responseTime < 200;

10.状态码为200：

tests["Status code is 200"] = responseCode.code === 200;

11.Code name contains a string：

tests["Status code name has string"] = responseCode.name.has("Created");

12.成功的POST request状态码：

tests["Successful POST request"] = responseCode.code === 201 || responseCode.code === 202;

13.Use TinyValidator for JSON data

var schema = {
    "items": {
     "type": "boolean"
     }
};
var data1 = [true, false];
var data2 = [true, 123];

console.log(tv4.error);
tests["Valid Data1"] = tv4.validate(data1, schema);
tests["Valid Data2"] = tv4.validate(data2, schema);

14.Sample data files

JSON files are composed of key/value pairs：

Download JSON file

For CSV files, the top row needs to contain variable names

Download CSV file

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