pytest 的基本使用方法

1、斷言

　　在 unittest 單元測試框架中提供了豐富的斷言方法，如 assertEqual()、assertIn()、assertTrue()、assertIs()等。pytest 單元測試框架並沒有提供專門的斷言方法，而是直接使用Python 的 assert 進行斷言。 　　建立 test_assert.py 檔案

# -*- coding:utf-8 -*-
# filename: test_assert.py
# author: hello.yin
# date: 2021/11/18

import pytest

# 建立用於測試的功能函式


#
 
 加法測試
def add(a, b):
    return a + b


# 判斷素數
def is_prime(n):
    if n < 2:
        return False
    else:
        for i in range(2, n):
            if n % i == 0:
                return False
            else:
                return True


# 判斷相等
def test_add1():
    assert add(3, 5) == 8

# 判斷大於
 

def test_add2():
    assert add(5, 5) > 10


# 判斷為True
def test_isprime1():
    assert is_prime(1) is False


# 判斷為False
def test_isprime2():
    assert is_prime(7) is True


# 判斷包含
def test_in():
    a = "he"
    b = "hello"
    assert a in b


# 判斷不包含
def test_not_in():
    a = "yin"
    b = "hello
 
"
    assert a not in b


if __name__ == "__main__":
    pytest.main()

　　執行結果：

(base_practice) D:\00test\base_practice\pyTest>pytest test_assert.py
=============================================================== test session starts ===============================================================
platform win32 -- Python 3.7.4, pytest-6.2.5, py-1.11.0, pluggy-1.0.0
rootdir: D:\00test\base_practice\pyTest
collected 6 items                                                                                                                                  

test_assert.py .F....                                                                                                                        [100%]

==================================================================== FAILURES =====================================================================
____________________________________________________________________ test_add2 ____________________________________________________________________

    def test_add2():
>       assert add(5, 5) > 10
E    assert 10 > 10
E     +  where 10 = add(5, 5)

test_assert.py:34: AssertionError
============================================================= short test summary info =============================================================
FAILED test_assert.py::test_add2 - assert 10 > 10
=========================================================== 1 failed, 5 passed in 0.06s ===========================================================

　　上面的例子展示了 pytest 斷言的用法，藉助 Python 的運算子號和關鍵字即可輕鬆實現不同資料型別的斷言。

2、Fixture

　　Fixture 通常用來對測試方法、測試函式、測試類和整個測試檔案進行初始化或還原測試環境。建立 test_fixtures_01.py 檔案。

# -*- coding:utf -8 -*-
# filename: /pyTest/test_fixtrue.py
# author: hello.yin
# date: 2021/11/18


# 功能函式
def mul(a, b):
    return a*b


# 模組級別
def setup_module(module):
    print("===========setup_module=========")


def teardown_module(module):
    print("============teardown_module========")


# 函式級別
def setup_function(function):
    print("==========setup_founction=========")


def teardown_function(function):
    print("==========setup_founction==========")


# 用例級別
def setup():
    print("==========setup=========")


def teardown():
    print("=========teardowm==========")


# 測試用例
def test_35():
    assert mul(3, 5) == 14

def test_45():
    assert mul(4, 5) == 20

　　這裡主要用到模組級別和函式級別的 Fixture。

• setup_module/teardown_module：在當前檔案中，在所有測試用例執行之前與之後執行。
• setup_function/teardown_function：在每個測試函式之前與之後執行。
• setup/teardown：在每個測試函式之前與之後執行。這兩個方法同樣可以作用於類方法。

　　執行結果：

(base_practice) D:\00test\base_practice\pyTest>pytest test_fixtrue01.py
=============================================================== test session starts ===============================================================
platform win32 -- Python 3.7.4, pytest-6.2.5, py-1.11.0, pluggy-1.0.0
rootdir: D:\00test\base_practice\pyTest
collected 2 items                                                                                                                                  

test_fixtrue01.py F.                                                                                                                         [100%]

==================================================================== FAILURES =====================================================================
_____________________________________________________________________ test_35 _____________________________________________________________________

    def test_35():
>       assert mul(3, 5) == 14
E    assert 15 == 14
E     +  where 15 = mul(3, 5)

test_fixtrue01.py:41: AssertionError
-------------------------------------------------------------- Captured stdout setup --------------------------------------------------------------
===========setup_module=========
==========setup_founction=========
==========setup=========
------------------------------------------------------------ Captured stdout teardown -------------------------------------------------------------
=========teardowm==========
==========setup_founction==========
============================================================= short test summary info =============================================================
FAILED test_fixtrue01.py::test_35 - assert 15 == 14
=========================================================== 1 failed, 1 passed in 0.05s ===========================================================

　　pytest 是支援使用測試類的，同樣必須以“Test”開頭，注意首字母大寫。在引入測試類的情況下，Fixture 的用法如下。建立 test_fixtures_02.py 檔案。

# -*- coding:utf-8 -*-
# filename: test_fixtrue02.py
# author: hello.yin
# date: 2021/11/18


# 功能函式
def mul(a, b):
    return a*b


# 判斷函式類
class TestMul:

    @classmethod
    def setup_class(cls):
        print("===============setup_class===============")

    @classmethod
    def teardown_class(cls):
        print("===============teardown_class==============")

    @staticmethod
    def setup_method(self):
        print("==============setup_method=================")

    @staticmethod
    def teardown_method(self):
        print("==============teardown_method==============")

    @staticmethod
    def setup():
        print("==========setup=============")

    @staticmethod
    def teardown():
        print("===========teardown============")

    # 測試用例
    def test_mul35(self):
        assert mul(3, 5) == 16

    def test_mul45(self):
        assert mul(4, 5) == 20

這裡主要用到類級別和方法級別的 Fixture。

• setup_class/teardown_class ：在當前測試類的開始與結束時執行。
• setup_method/teardown_method ：在每個測試方法開始與結束時執行。
• setup/teardown ：在每個測試方法開始與結束時執行，同樣可以作用於測試函式。

執行結果：

(base_practice) D:\00test\base_practice\pyTest>pytest test_fixtrue02.py
=============================================================== test session starts ===============================================================
platform win32 -- Python 3.7.4, pytest-6.2.5, py-1.11.0, pluggy-1.0.0
rootdir: D:\00test\base_practice\pyTest
collected 2 items                                                                                                                                  

test_fixtrue02.py F.                                                                                                                         [100%]

==================================================================== FAILURES =====================================================================
_______________________________________________________________ TestMul.test_mul35 ________________________________________________________________

self = <pyTest.test_fixtrue02.TestMul object at 0x0000026A7E40D108>

    def test_mul35(self):
>       assert mul(3, 5) == 16
E    assert 15 == 16
E     +  where 15 = mul(3, 5)

test_fixtrue02.py:41: AssertionError
-------------------------------------------------------------- Captured stdout setup --------------------------------------------------------------
===============setup_class===============
==============setup_method=================
==========setup=============
------------------------------------------------------------ Captured stdout teardown -------------------------------------------------------------
===========teardown============
==============teardown_method==============
============================================================= short test summary info =============================================================
FAILED test_fixtrue02.py::TestMul::test_mul35 - assert 15 == 16
=========================================================== 1 failed, 1 passed in 0.05s ===========================================================

3、 引數化

當一組測試用例有固定的測試資料時，就可以通過引數化的方式簡化測試用例的編寫。pytest 本身是支援引數化的，不需要額外安裝外掛。建立 test_parameterize.py 檔案。

# -*- coding:utf-8 -*-
# filename: test_parameterized.py
# author: hello.yin
# date: 20221/11/18

import pytest
import math


@pytest.mark.parametrize(
    "base, exponent, expected",
    ((2, 2, 4),
     (3, 3, 9),
     (2, 3, 8),
     (0, 9, 0)),
    ids=["case1", "case2", "case3", "case4"])
def test_row(base, exponent, expected):
    assert math.pow(base, exponent) == expected

　　用法與 unittest 的引數化外掛類似，通過 pytest.mark.parametrize()方法設定引數。“base,exponent,expected”用來定義引數的名稱。通過陣列定義引數時，每一個元組都是一條測試用例使用的測試資料。ids 引數預設為 None，用於定義測試用例的名稱。math 模組的 pow()方法用於計算 xy（x 的 y 次方）的值。

　　執行結果如下：

(base_practice) D:\00test\base_practice\pyTest>pytest -v test_parameterized.py
=============================================================== test session starts ===============================================================
platform win32 -- Python 3.7.4, pytest-6.2.5, py-1.11.0, pluggy-1.0.0 -- C:\Users\yzp\PycharmProjects\base_practice\Scripts\python.exe
cachedir: .pytest_cache
rootdir: D:\00test\base_practice\pyTest
collected 4 items                                                                                                                                  

test_parameterized.py::test_row[case1] PASSED                                                                                                [ 25%]
test_parameterized.py::test_row[case2] FAILED                                                                                                [ 50%]
test_parameterized.py::test_row[case3] PASSED                                                                                                [ 75%]
test_parameterized.py::test_row[case4] PASSED                                                                                                [100%]

==================================================================== FAILURES =====================================================================
_________________________________________________________________ test_row[case2] _________________________________________________________________

base = 3, exponent = 3, expected = 9

    @pytest.mark.parametrize(
        "base, exponent, expected",
        ((2, 2, 4),
         (3, 3, 9),
         (2, 3, 8),
         (0, 9, 0)),
        ids=["case1", "case2", "case3", "case4"])
    def test_row(base, exponent, expected):
>       assert math.pow(base, exponent) == expected
E    assert 27.0 == 9
E      +27.0
E      -9

test_parameterized.py:18: AssertionError
============================================================= short test summary info =============================================================
FAILED test_parameterized.py::test_row[case2] - assert 27.0 == 9
=========================================================== 1 failed, 3 passed in 0.04s ===========================================================

4、 執行測試

　　pytest 提供了豐富的引數執行測試用例，在前面的例子中已經使用到一些引數，例如，“-s”引數用於關閉捕捉，從而輸出列印資訊；“-v”引數用於增加測試用例冗長。　 　　通過“pytest --help”可以檢視幫助：

 pytest––help

　　pytest 提供的引數比較多，下面只介紹常用的引數：

4.1．執行名稱中包含某字串的測試用例

　　在前面內容test_assert.py 檔案，其中有 42條是關於 add()功能的，並且在測試用例的名稱上包含了“add”字串，因此這裡可以通過“-k”來指定在名稱中包含“add”的測試用例。

(base_practice) D:\00test\base_practice\pyTest>pytest -k add test_assert.py
=============================================================== test session starts ===============================================================
platform win32 -- Python 3.7.4, pytest-6.2.5, py-1.11.0, pluggy-1.0.0
rootdir: D:\00test\base_practice\pyTest
collected 6 items / 4 deselected / 2 selected                                                                                                      

test_assert.py .F                                                                                                                            [100%]

==================================================================== FAILURES =====================================================================
____________________________________________________________________ test_add2 ____________________________________________________________________

    def test_add2():
>       assert add(5, 5) > 10
E    assert 10 > 10
E     +  where 10 = add(5, 5)

test_assert.py:34: AssertionError
============================================================= short test summary info =============================================================
FAILED test_assert.py::test_add2 - assert 10 > 10
==================================================== 1 failed, 1 passed, 4 deselected in 0.04s ====================================================

4.2．減少測試的執行冗長

這一次執行日誌少了很多資訊，“-q”用來減少測試執行的冗長；也可以使用“--quiet”代替

(base_practice) D:\00test\base_practice\pyTest>pytest -q  test_assert.py
.F....                                                                                                                                       [100%]
==================================================================== FAILURES =====================================================================
____________________________________________________________________ test_add2 ____________________________________________________________________

    def test_add2():
>       assert add(5, 5) > 10
E    assert 10 > 10
E     +  where 10 = add(5, 5)

test_assert.py:34: AssertionError
============================================================= short test summary info =============================================================
FAILED test_assert.py::test_add2 - assert 10 > 10
1 failed, 5 passed in 0.03s

4.3. 如果出現一條測試用例失敗，則退出測試

　　這在測試用例的除錯階段是有用的，當出現一條失敗的測試用例時，應該先通過除錯讓這條測試用例執行通過，而不是繼續執行後面的測試用例。

(base_practice) D:\00test\base_practice\pyTest>pytest -x  test_assert.py
=============================================================== test session starts ===============================================================
platform win32 -- Python 3.7.4, pytest-6.2.5, py-1.11.0, pluggy-1.0.0
rootdir: D:\00test\base_practice\pyTest
collected 6 items                                                                                                                                  

test_assert.py .F

==================================================================== FAILURES =====================================================================
____________________________________________________________________ test_add2 ____________________________________________________________________

    def test_add2():
>       assert add(5, 5) > 10
E    assert 10 > 10
E     +  where 10 = add(5, 5)

test_assert.py:34: AssertionError
============================================================= short test summary info =============================================================
FAILED test_assert.py::test_add2 - assert 10 > 10
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! stopping after 1 failures !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
=========================================================== 1 failed, 1 passed in 0.04s ===========================================================

4.4．執行測試目錄

　　測試目錄既可以指定相對路徑（如 ./test_dir ） ， 也 可以指定絕對路徑（如D:\00test\base_practice\pyTest）

(base_practice) D:\00test\base_practice\pyTest>pytest D:\00test\base_practice\pyTest
=============================================================== test session starts ===============================================================
platform win32 -- Python 3.7.4, pytest-6.2.5, py-1.11.0, pluggy-1.0.0
rootdir: D:\00test\base_practice\pyTest
collected 15 items                                                                                                                                 

test_assert.py .F....                                                                                                                        [ 40%]
test_fixtrue01.py F.                                                                                                                         [ 53%]
test_fixtrue02.py F.                                                                                                                         [ 66%]
test_parameterized.py .F..                                                                                                                   [ 93%]
test_sample.py F                                                                                                                             [100%]

==================================================================== FAILURES =====================================================================
____________________________________________________________________ test_add2 ____________________________________________________________________

    def test_add2():
>       assert add(5, 5) > 10
E    assert 10 > 10
E     +  where 10 = add(5, 5)

test_assert.py:34: AssertionError
_____________________________________________________________________ test_35 _____________________________________________________________________

    def test_35():
>       assert mul(3, 5) == 14
E    assert 15 == 14
E     +  where 15 = mul(3, 5)

test_fixtrue01.py:41: AssertionError
-------------------------------------------------------------- Captured stdout setup --------------------------------------------------------------
===========setup_module=========
==========setup_founction=========
==========setup=========
------------------------------------------------------------ Captured stdout teardown -------------------------------------------------------------
=========teardowm==========
==========setup_founction==========
_______________________________________________________________ TestMul.test_mul35 ________________________________________________________________

self = <pyTest.test_fixtrue02.TestMul object at 0x00000276153A5F88>

    def test_mul35(self):
>       assert mul(3, 5) == 16
E    assert 15 == 16
E     +  where 15 = mul(3, 5)

test_fixtrue02.py:41: AssertionError
-------------------------------------------------------------- Captured stdout setup --------------------------------------------------------------
===============setup_class===============
==============setup_method=================
==========setup=============
------------------------------------------------------------ Captured stdout teardown -------------------------------------------------------------
===========teardown============
==============teardown_method==============
_________________________________________________________________ test_row[case2] _________________________________________________________________

base = 3, exponent = 3, expected = 9

    @pytest.mark.parametrize(
        "base, exponent, expected",
        ((2, 2, 4),
         (3, 3, 9),
         (2, 3, 8),
         (0, 9, 0)),
        ids=["case1", "case2", "case3", "case4"])
    def test_row(base, exponent, expected):
>       assert math.pow(base, exponent) == expected
E    assert 27.0 == 9
E     +  where 27.0 = <built-in function pow>(3, 3)
E     +    where <built-in function pow> = math.pow

test_parameterized.py:18: AssertionError
___________________________________________________________________ test_answer ___________________________________________________________________

    def test_answer():
>       assert inc(3) == 5
E    assert 4 == 5
E     +  where 4 = inc(3)

test_sample.py:13: AssertionError
============================================================= short test summary info =============================================================
FAILED test_assert.py::test_add2 - assert 10 > 10
FAILED test_fixtrue01.py::test_35 - assert 15 == 14
FAILED test_fixtrue02.py::TestMul::test_mul35 - assert 15 == 16
FAILED test_parameterized.py::test_row[case2] - assert 27.0 == 9
FAILED test_sample.py::test_answer - assert 4 == 5
========================================================== 5 failed, 10 passed in 0.13s ===========================================================

4.5．指定特定類或方法執行

這裡指定執行 test_fixtures_02.py 檔案中 TestMul 類下的test_mul35()方法，檔名、類名和方法名之間用“::”符號分隔

(base_practice) D:\00test\base_practice\pyTest>pytest test_fixtrue02.py::TestMul::test_mul35
=============================================================== test session starts ===============================================================
platform win32 -- Python 3.7.4, pytest-6.2.5, py-1.11.0, pluggy-1.0.0
rootdir: D:\00test\base_practice\pyTest
collected 1 item                                                                                                                                   

test_fixtrue02.py F                                                                                                                          [100%]

==================================================================== FAILURES =====================================================================
_______________________________________________________________ TestMul.test_mul35 ________________________________________________________________

self = <pyTest.test_fixtrue02.TestMul object at 0x0000027E785C9808>

    def test_mul35(self):
>       assert mul(3, 5) == 16
E    assert 15 == 16
E     +  where 15 = mul(3, 5)

test_fixtrue02.py:41: AssertionError
-------------------------------------------------------------- Captured stdout setup --------------------------------------------------------------
===============setup_class===============
==============setup_method=================
==========setup=============
------------------------------------------------------------ Captured stdout teardown -------------------------------------------------------------
===========teardown============
==============teardown_method==============
===============teardown_class==============
============================================================= short test summary info =============================================================
FAILED test_fixtrue02.py::TestMul::test_mul35 - assert 15 == 16
================================================================ 1 failed in 0.04s ================================================================

4.6．通過 main()方法執行測試

import pytest
    if __name__ == '__main__':
    pytest.main(['-s', './test_dir'])

建立 run_tests.py 檔案，在檔案中通過陣列指定引數，每個引數為陣列中的一個元素。

5、生成測試報告

pytest 支援生成多種格式的測試報告。

5.1生成 JUnit XML 檔案

> pytest ./test_dir --junit-xml=./report/log.xml

XML 型別的日誌主要用於存放測試結果，方便我們利用裡面的資料定製自己的測試報告。XML 格式的測試報告如圖所示。

執行結果：

(base_practice) D:\00test\base_practice\pyTest>pytest test_assert.py --junit-xml=./report/log.xml
=============================================================== test session starts ===============================================================
platform win32 -- Python 3.7.4, pytest-6.2.5, py-1.11.0, pluggy-1.0.0
rootdir: D:\00test\base_practice\pyTest
collected 6 items                                                                                                                                  

test_assert.py .F....                                                                                                                        [100%]

==================================================================== FAILURES =====================================================================
____________________________________________________________________ test_add2 ____________________________________________________________________

    def test_add2():
>       assert add(5, 5) > 10
E    assert 10 > 10
E     +  where 10 = add(5, 5)

test_assert.py:34: AssertionError
---------------------------------------- generated xml file: D:\00test\base_practice\pyTest\report\log.xml ----------------------------------------
============================================================= short test summary info =============================================================
FAILED test_assert.py::test_add2 - assert 10 > 10
=========================================================== 1 failed, 5 passed in 0.06s ===========================================================

6、conftest.py

　　conftest.py 是 pytest 特有的本地測試配置檔案，既可以用來設定專案級別的 Fixture，也可以用來匯入外部外掛，還可以用來指定鉤子函式。 　　建立 test_project/conftest.py 測試配置檔案。 　　需要說明的是，conftest.py 只作用於它所在的目錄及子目錄。

　　建立 test_project/conftest.py 測試配置檔案

import pytest

@pytest.fixture()
def test_url():
    return "https://www.baidu.com"

　　建立 test_project/test_sub.py 測試用例檔案

def test_baidu(test_url):
    print(test_url)

　　這裡建立的函式可以直接呼叫 conftest.py 檔案中的 test_url()鉤子函式，測試結果如下

(base_practice) D:\00test\base_practice\pyTest>pytest -v -s test_project\
=============================================================== test session starts ===============================================================
platform win32 -- Python 3.7.4, pytest-6.2.5, py-1.11.0, pluggy-1.0.0 -- C:\Users\yzp\PycharmProjects\base_practice\Scripts\python.exe
cachedir: .pytest_cache
rootdir: D:\00test\base_practice\pyTest
collected 1 item                                                                                                                                   

test_project/test_sub.py::test_baidu https://www.baidu.com
PASSED

================================================================ 1 passed in 0.01s ================================================================

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本文來自部落格園，作者：hello_殷，轉載請註明原文連結：https://www.cnblogs.com/yinzuopu/p/15572779.html

本文版權歸作者和部落格園共有，歡迎轉載，但必須給出原文連結，並保留此段宣告，否則保留追究法律責任的權利。