Python 如何在每个单元测试中重置夹具的某些属性？

你们中有谁能告诉我如何在每个单元测试中改变夹具吗

在以下示例中，我想：

• 执行

  start\u driver（）

  仅一次-这是一个长时间运行的操作，因此我使用

  scope=session

  初始化这个装置
• 在每个单元测试中，将驱动器计数器重置为0

代码：

import pytest
import time

def start_driver():
    # some long running operations
    time.sleep(3)

def increment(driver):
    driver.counter += 1
    return driver.counter

class DriverInstance():
    def __init__(self):
        self.driver = start_driver()
        self.counter = 0

@pytest.fixture(scope='session')
def driver():
    yield DriverInstance()

def test_driver_1(driver):
    assert increment(driver) == 1

def test_driver_2(driver):
    assert increment(driver) == 1

$ pytest driver.py
========================================= test session starts ==========================================
platform linux -- Python 3.7.1, pytest-5.0.1, py-1.7.0, pluggy-0.12.0
rootdir: /home/backend/backend, inifile: pytest.ini
plugins: mock-1.10.4
collected 2 items

driver.py .F                                                                                     [100%]

=============================================== FAILURES ===============================================
____________________________________________ test_driver_2 _____________________________________________

driver = <driver.DriverInstance object at 0x7f78a5b000b8>

    def test_driver_2(driver):
>       assert increment(driver) == 1
E       assert 2 == 1
E        +  where 2 = increment(<driver.DriverInstance object at 0x7f78a5b000b8>)

driver.py:25: AssertionError
================================== 1 failed, 1 passed in 3.03 seconds ==================================

Pytest执行：

import pytest
import time

def start_driver():
    # some long running operations
    time.sleep(3)

def increment(driver):
    driver.counter += 1
    return driver.counter

class DriverInstance():
    def __init__(self):
        self.driver = start_driver()
        self.counter = 0

@pytest.fixture(scope='session')
def driver():
    yield DriverInstance()

def test_driver_1(driver):
    assert increment(driver) == 1

def test_driver_2(driver):
    assert increment(driver) == 1

$ pytest driver.py
========================================= test session starts ==========================================
platform linux -- Python 3.7.1, pytest-5.0.1, py-1.7.0, pluggy-0.12.0
rootdir: /home/backend/backend, inifile: pytest.ini
plugins: mock-1.10.4
collected 2 items

driver.py .F                                                                                     [100%]

=============================================== FAILURES ===============================================
____________________________________________ test_driver_2 _____________________________________________

driver = <driver.DriverInstance object at 0x7f78a5b000b8>

    def test_driver_2(driver):
>       assert increment(driver) == 1
E       assert 2 == 1
E        +  where 2 = increment(<driver.DriverInstance object at 0x7f78a5b000b8>)

driver.py:25: AssertionError
================================== 1 failed, 1 passed in 3.03 seconds ==================================

$pytest driver.py
===============================================================测试会话开始==========================================
平台linux——Python 3.7.1、pytest-5.0.1、py-1.7.0、pluggy-0.12.0
rootdir:/home/backend/backend，ini文件：pytest.ini
插件：mock-1.10.4
收集2项
driver.py.F[100%]
==================================================================故障===============================================
____________________________________________测试驱动程序2_____________________________________________
驱动程序=
def测试驱动程序2（驱动程序）：
>断言增量（驱动程序）==1
E断言2==1
E+式中，2=增量（）
driver.py:25:AssertionError
==========================================================1失败，1在3.03秒内通过==================================

例如，引入另一个将重置计数器的装置

@pytest.fixture(autouse=True)
def reset_counter(driver):
    driver.counter = 0

---

由于

autouse=True

，将自动执行

reset\u计数器

，并且由于默认范围是

函数

，它将在每次测试前执行一次。

driver

参数将引用

driver

fixture的返回值（fixture args，就像test args一样，也通过fixture名称解析）。

很高兴我能提供帮助！