[TOC]python

pytest

安裝與入門

1.pip install -U pytest

2.建立一個test01.py的文件

def func(x):
    return x + 1

def test_answer():
    assert func(3) == 5

3.在該目錄下執行pytest(venv)

D:\4_code\study>pytest ============================= test session starts ============================= platform win32 -- Python 3.6.2, pytest-3.7.1, py-1.5.4, pluggy-0.7.1 rootdir: D:\4_code\study, inifile: collected 1 itemjson

test01.py . [100%]session

========================== 1 passed in 0.19 seconds ===========================ide

(venv) D:\4_code\study>pytest測試

4.執行多個，新建一個py文件 test02.py

def add(x, y):
    return x + y

def test_add():
    assert add(1, 0) == 1
    assert add(1, 1) == 2
    assert add(1, 99) == 100

執行pytestui

(venv) D:\4_code\study>pytest ============================= test session starts ============================= platform win32 -- Python 3.6.2, pytest-3.7.1, py-1.5.4, pluggy-0.7.1 rootdir: D:\4_code\study, inifile: collected 2 itemsthis

test01.py . [ 50%] test02.py . [100%]url

========================== 2 passed in 0.30 seconds ===========================spa

pytest將在當前目錄及其子目錄中運行test _ * .py或* _test.py形式的全部文件。.net

5.在一個類中組合多個測試

一旦開發了多個測試，您可能但願將它們分組到一個類中。pytest能夠很容易地建立一個包含多個測試的類：

class TestClass(object):
    def test_one(self):
        x = "this"
        assert 'h' in x

    def test_two(self):
        x = "hello"
        assert hasattr(x, 'check')

test_calc.py . [ 25%] test_class.py .F [ 75%] test_quick_start.py . [100%]

================================== FAILURES =================================== _____________________________ TestClass.test_two ______________________________

self = <test_class.TestClass object at 0x058A59F0>

def test_two(self):
    x = "hello"

assert hasattr(x, 'check')
  E       AssertionError: assert False
  E        +  where False = hasattr('hello', 'check')

test_class.py:16: AssertionError ===================== 1 failed, 3 passed in 0.37 seconds ======================

6.指定測試用例

(venv) D:\4_code\study>pytest -q test_calc.py . [100%] 1 passed in 0.02 seconds

7.Assert

pytest使用的是python自帶的assert關鍵字來進行斷言 assert關鍵字後面能夠接一個表達式，只要表達式的最終結果爲True，那麼斷言經過，用例執行成功，不然用例執行失敗

斷言異常拋出如

import pytest

def test_zero_division():
    with pytest.raises(ZeroDivisionError):
        1 / 0

1/0的時候應該拋出ZeroDivisionError，不然用例失敗，斷言不經過。

8.Fixture

如測試數據爲

[
  {"name":"jack","password":"Iloverose"},
  {"name":"rose","password":"Ilovejack"},
  {"name":"tom","password":"password123"}
]

import pytest
import json

class TestUserPassword(object):
    @pytest.fixture
    def users(self):
        return json.loads(open('./users.dev.json', 'r').read()) # 讀取當前路徑下的users.dev.json文件，返回的結果是dict

    def test_user_password(self, users):
        # 遍歷每條user數據
        for user in users:
            passwd = user['password']
            assert len(passwd) >= 6
            msg = "user %s has a weak password" %(user['name'])
            assert passwd != 'password', msg
            assert passwd != 'password123', msg

(venv) D:\4_code\study>pytest test_user_password.py
============================= test session starts =============================
platform win32 -- Python 3.6.2, pytest-3.7.1, py-1.5.4, pluggy-0.7.1
rootdir: D:\4_code\study, inifile:
collected 1 item                                                               

test_user_password.py F                                                  [100%]

================================== FAILURES ===================================
_____________________ TestUserPassword.test_user_password _____________________

self = <test_user_password.TestUserPassword object at 0x044783B0>
users = [{'name': 'jack', 'password': 'Iloverose'}, {'name': 'rose', 'password': 'Ilovejack'}, {'name': 'tom', 'password': 'password123'}]

    def test_user_password(self, users):
        # 遍歷每條user數據
        for user in users:
            passwd = user['password']
            assert len(passwd) >= 6
            msg = "user %s has a weak password" %(user['name'])
            assert passwd != 'password', msg
>           assert passwd != 'password123', msg
E           AssertionError: user tom has a weak password
E           assert 'password123' != 'password123'

test_user_password.py:16: AssertionError
========================== 1 failed in 0.26 seconds ===========================

使用@pytest.fixture裝飾器能夠定義feature 在用例的參數中傳遞fixture的名稱以便直接調用fixture，拿到fixture的返回值 3個assert是遞進關係，前1個assert斷言失敗後，後面的assert是不會運行的，所以重要的assert放到前面 E AssertionError: user tom has a weak password能夠很容易的判斷出是哪條數據出了問題，因此定製可讀性好的錯誤信息是很必要的任何1個斷言失敗之後，for循環就會退出，因此上面的用例1次只能發現1條錯誤數據，換句話說任何1個assert失敗後，用例就終止運行了

執行順序

pytest找到以test_開頭的方法，也就是test_user_password方法，執行該方法時發現傳入的參數裏有跟fixture users名稱相同的參數 pytest認定users是fixture，執行該fixture，讀取json文件解析成dict實例 test_user_password方法真正被執行，users fixture被傳入到該方法

使用下面的命令來查看用例中可用的fixtures

pytest --fixtures test_user_password.py

------------------ fixtures defined from test_user_password -------------------
users
    test_user_password.py:6: no docstring available

======================== no tests ran in 0.07 seconds =========================

數據清理

有時候咱們須要在用例結束的時候去清理一些測試數據，或清除測試過程當中建立的對象，咱們能夠使用下面的方式

import smtplib
import pytest

@pytest.fixture(scope="module")
def smtp():
    smtp = smtplib.SMTP("smtp.gmail.com", 587, timeout=5)
    yield smtp  # provide the fixture value
    print("teardown smtp")
    smtp.close()
yield 關鍵字返回了fixture中實例化的對象smtp
module中的用例執行完成後smtp.close()方法會執行，不管用例的運行狀態是怎麼樣的,都會執行

pytest_01_安裝和入門