什么是BDD测试？框架示例

什么是BDD（行为驱动开发）测试？

BDD（行为驱动开发）测试是一种敏捷软件开发技术，是TDD（测试驱动开发）的扩展。在BDD中，测试用例以自然语言编写，即使是非程序员也能阅读。

BDD测试如何工作？

假设你被指派在网上银行应用程序中创建资金转账模块。

有多种方法可以测试它

如果源账户有足够的余额，则应进行资金转账
如果目标账户详情正确，则应进行资金转账
如果用户输入的交易密码/rsa代码/交易安全认证正确，则应进行资金转账
即使是银行假日，也应进行资金转账
应在账户持有人设定的未来日期进行资金转账

当我们考虑更多功能，例如在Y天/月内转账X金额，当总金额达到Z时停止定期转账等等时，测试场景变得更加复杂

开发人员的普遍倾向是先开发功能，再编写测试代码。如上例所示，此案例的测试用例开发很复杂，开发人员会将测试推迟到发布，届时他将进行快速但不有效的测试。

为了克服这个问题，BDD（行为驱动开发）应运而生。它使整个测试过程对开发人员来说变得简单

在BDD中，你编写的所有内容都必须遵循Given-When-Then步骤。让我们考虑上面相同的BDD示例

Given that a fund transfer module in net banking application has been developed
And I am accessing it with proper authentication

WhenI shall transfer with enough balance in my source account
Or I shall transfer on a Bank Holiday
Or I shall transfer on a future date
And destination a/c details are correct
And transaction password/rsa code / security authentication for the transaction is correct
And press or click send button

Then amount must be transferred
And the event will be logged in log file

是不是很容易编写、阅读和理解？它涵盖了资金转账模块的所有可能测试用例，并且可以轻松修改以适应更多情况。此外，它更像是为资金转账模块编写文档。

什么是REST API测试？

由于REST如今已成为构建API的流行风格，因此自动化REST API测试用例以及UI测试用例变得同样重要。因此，这些REST API测试主要涉及使用POST、GET、PUT和DELETE方法分别测试CRUD（创建-读取-更新-删除）操作。

什么是Behave？

Behave是流行的Python BDD测试框架之一。

让我们看看Behave是如何运作的

功能文件由你的业务分析师/发起人/任何人在其中编写，包含你的行为场景。它具有自然语言格式，描述了一个功能或功能的一部分，并附有预期结果的代表性示例

这些场景步骤与用Python编写的步骤实现相映射。

并且，可选地，还有一些环境控制（在步骤、场景、功能或整个匹配之前和之后运行的代码）。

让我们开始使用Behave设置我们的自动化测试框架

在Windows上设置BDD测试框架Behave

安装

从https://pythonlang.cn/下载并安装Python 3
在命令提示符下执行以下命令以安装behave
pip install behave
IDE：我使用了PyCharm Community Edition https://www.jetbrains.com/pycharm/download

项目设置

创建一个新项目
创建以下目录结构

功能文件

因此，让我们构建我们的功能文件Sample_REST_API_Testing.feature，其功能是对“帖子”服务执行CRUD操作。

在我们的示例中，我使用了http://jsonplaceholder.typicode.com/ posts 示例 REST 服务。

POST场景示例

Scenario: POST post example ->Here we are considering creating new post item using 'posts' service
Given: I set post posts API endpoint ->This is prerequisite for the test which is setting URL of posts service
When: I set HEADER param request content type as "application/json."
And set request body
And send POST HTTP request ->This is actual test step of sending a post request
Then: Then I receive valid HTPP response code 201 
And Response body "POST" is non-empty-> This is verification of response body

同样，你可以按如下方式编写其余场景

Sample_REST_API_Testing.feature

Feature: Test CRUD methods in Sample REST API testing framework

Background:
	Given I set sample REST API url

Scenario: POST post example
  Given I Set POST posts api endpoint
 When I Set HEADER param request content type as "application/json." 
    And Set request Body
 And Send a POST HTTP request 
 Then I receive valid HTTP response code 201
    And Response BODY "POST" is non-empty. 


Scenario: GET posts example
  Given I Set GET posts api endpoint "1"
  When I Set HEADER param request content type as "application/json." 
	And Send GET HTTP request
  Then I receive valid HTTP response code 200 for "GET." 
	And Response BODY "GET" is non-empty


Scenario: UPDATE posts example
  Given I Set PUT posts api endpoint for "1"
  When I Set Update request Body
	And Send PUT HTTP request
  Then I receive valid HTTP response code 200 for "PUT." 
	And Response BODY "PUT" is non-empty


Scenario: DELETE posts example
  Given I Set DELETE posts api endpoint for "1"
  When I Send DELETE HTTP request
  Then I receive valid HTTP response code 200 for "DELETE."

步骤实现

现在，对于上述场景中使用的功能步骤，你可以在“steps”目录中的 Python 文件中编写实现。

Behave 框架通过与功能文件谓词匹配的装饰器来识别步骤函数。例如，功能文件场景中的 Given 谓词会搜索带有装饰器“given”的步骤函数。When 和 Then 也会发生类似的匹配。但对于“But”和“And”的情况，步骤函数采用与其前一个步骤相同的装饰器。例如，如果“And”出现在 Given 之后，则匹配的步骤函数装饰器为 @given。

例如，POST 的步骤可以实现如下

@when (u'I Set HEADER param request content type as "{header_conent_type}"')
Mapping of When, here notice “application/json” is been passed from feature file for "{header_conent_type}” . This is called as parameterization


def step_impl (context, header_conent_type):
This is step implementation method signature

request_headers['Content-Type'] = header_conent_type
Step implementation code, here you will be setting content type for request header

同样，步骤 Python 文件中其他步骤的实现将如下所示

sample_step_implementation.py

from behave import given, when, then, step
import requests

api_endpoints = {}
request_headers = {}
response_codes ={}
response_texts={}
request_bodies = {}
api_url=None

@given(u'I set sample REST API url')
def step_impl(context):
    global api_url
    api_url = 'http://jsonplaceholder.typicode.com'

# START POST Scenario
@given(u'I Set POST posts api endpoint')
def step_impl(context):
    api_endpoints['POST_URL'] = api_url+'/posts'
    print('url :'+api_endpoints['POST_URL'])

@when(u'I Set HEADER param request content type as "{header_conent_type}"')
def step_impl(context, header_conent_type):
    request_headers['Content-Type'] = header_conent_type

#You may also include "And" or "But" as a step - these are renamed by behave to take the name of their preceding step, so:
@when(u'Set request Body')
def step_impl(context):
    request_bodies['POST']={"title": "foo","body": "bar","userId": "1"}

#You may also include "And" or "But" as a step - these are renamed by behave to take the name of their preceding step, so:
@when(u'Send POST HTTP request')
def step_impl(context):
    # sending get request and saving response as response object
    response = requests.post(url=api_endpoints['POST_URL'], json=request_bodies['POST'], headers=request_headers)
    #response = requests.post(url=api_endpoints['POST_URL'], headers=request_headers) #https://jsonplaceholder.typicode.com/posts
    # extracting response text
    response_texts['POST']=response.text
    print("post response :"+response.text)
    # extracting response status_code
    statuscode = response.status_code
    response_codes['POST'] = statuscode

@then(u'I receive valid HTTP response code 201')
def step_impl(context):
    print('Post rep code ;'+str(response_codes['POST']))
    assert response_codes['POST'] is 201
# END POST Scenario

# START GET Scenario
@given(u'I Set GET posts api endpoint "{id}"')
def step_impl(context,id):
    api_endpoints['GET_URL'] = api_url+'/posts/'+id
    print('url :'+api_endpoints['GET_URL'])

#You may also include "And" or "But" as a step - these are renamed by behave to take the name of their preceding step, so:
@when(u'Send GET HTTP request')
def step_impl(context):
    # sending get request and saving response as response object
    response = requests.get(url=api_endpoints['GET_URL'], headers=request_headers) #https://jsonplaceholder.typicode.com/posts
    # extracting response text
    response_texts['GET']=response.text
    # extracting response status_code
    statuscode = response.status_code
    response_codes['GET'] = statuscode

@then(u'I receive valid HTTP response code 200 for "{request_name}"')
def step_impl(context,request_name):
    print('Get rep code for '+request_name+':'+ str(response_codes[request_name]))
    assert response_codes[request_name] is 200

@then(u'Response BODY "{request_name}" is non-empty')
def step_impl(context,request_name):
    print('request_name: '+request_name)
    print(response_texts)
    assert response_texts[request_name] is not None
# END GET Scenario

#START PUT/UPDATE
@given(u'I Set PUT posts api endpoint for "{id}"')
def step_impl(context,id):
    api_endpoints['PUT_URL'] = api_url + '/posts/'+id
    print('url :' + api_endpoints['PUT_URL'])

@when(u'I Set Update request Body')
def step_impl(context):
    request_bodies['PUT']={"title": "foo","body": "bar","userId": "1","id": "1"}

@when(u'Send PUT HTTP request')
def step_impl(context):
    # sending get request and saving response as response object  # response = requests.post(url=api_endpoints['POST_URL'], headers=request_headers) #https://jsonplaceholder.typicode.com/posts
    response = requests.put(url=api_endpoints['PUT_URL'], json=request_bodies['PUT'], headers=request_headers)
    # extracting response text
    response_texts['PUT'] = response.text
    print("update response :" + response.text)
    # extracting response status_code
    statuscode = response.status_code
    response_codes['PUT'] = statuscode
#END PUT/UPDATE

#START DELETE
@given(u'I Set DELETE posts api endpoint for "{id}"')
def step_impl(context,id):
    api_endpoints['DELETE_URL'] = api_url + '/posts/'+id
    print('url :' + api_endpoints['DELETE_URL'])

@when(u'I Send DELETE HTTP request')
def step_impl(context):
    # sending get request and saving response as response object
    response = requests.delete(url=api_endpoints['DELETE_URL'])
    # response = requests.post(url=api_endpoints['POST_URL'], headers=request_headers) #https://jsonplaceholder.typicode.com/posts
    # extracting response text
    response_texts['DELETE'] = response.text
    print("DELETE response :" + response.text)
    # extracting response status_code
    statuscode = response.status_code
    response_codes['DELETE'] = statuscode
#END DELETE

运行测试

现在，我们的测试脚本开发部分已经完成，所以让我们运行测试

在命令提示符下执行以下命令来运行我们的功能文件

C:\Programs\Python\Python37>behave -f pretty C:\<你的项目路径>\features\feature_files_folder\Sample_REST_API_Testing.feature

这将显示测试执行结果如下

控制台上的报告显示

我们再来看看一个很棒的东西。

由于用户总是喜欢以更具可读性和更具表现力的格式查看测试结果，因此让我们借助 Allure 以 HTML 格式生成报告。

报告

首先，你需要安装 Allure Behave 格式化程序 [https://docs.qameta.io/allure-report/]

现在执行以下命令

用于报告

>behave -f json -o<你的报告文件夹路径> Sample_REST_API_Testing.feature

> allure serve <你的报告文件夹路径>

这将以这种可呈现且信息丰富的格式生成你的测试结果报告

HTML 格式的测试报告

显示单个场景结果的测试报告

摘要

BDD 是行为驱动开发。它是敏捷软件开发技术之一。
REST 如今已成为构建 API 的流行风格，因此自动化 REST API 测试用例以及 UI 测试用例变得同样重要。
BDD 具有自然语言格式，描述了一个功能或功能的一部分，并附有预期结果的代表性示例
Behave 框架通过与功能文件谓词匹配的装饰器来识别步骤函数
BDD 测试框架示例：1) Cucumber 2) SpecFlow 3) Quantum 4) JBehave 5) Codeception