如何使用 PyTest 捕获测试用例失败的屏幕截图

Question

目前我正在使用以下解决方案在 PyTest 的每个测试函数结束时截取屏幕截图。如何确保仅在测试失败时才截取屏幕截图？这是一个关于 PyTest 机制的问题。这个问题与 selenium 或 appium 无关。

我在 Stackoverflow 上发现了类似的问题，但并不完全相同。为其他问题提供的解决方案无法回答我的问题。由于使用 PyTest 对测试失败进行截图是一个常见问题，因此我认为它应该得到一个单独且非常具体的答案。

@pytest.fixture(scope="function", autouse=True)
def take_screenshot(self, appium_driver):
    yield
    time.sleep(1)
    current_filename_clean = os.path.basename(__file__).replace("test_", "").replace(".py", "")
    current_test_name = os.environ.get("PYTEST_CURRENT_TEST").split(":")[-1].split(" ")[0].replace("test_", "")
    appium_driver.get_screenshot_as_file(
        f'test_reports/{current_filename_clean}_android_{current_test_name}_{datetime.today().strftime("%Y-%m-%d")}.png')

Answer 1

这里是您的 conftest.py 文件的完整解决方案，用于在 docker 容器中无头运行：

import time
from datetime import datetime    
import pytest
import os
from selenium import webdriver as selenium_webdriver
from selenium.webdriver.chrome.options import Options

# set up webdriver fixture
@pytest.fixture(scope='session')
def selenium_driver(request):
    chrome_options = Options()
    chrome_options.add_argument('--headless')
    chrome_options.add_argument('--no-sandbox')
    chrome_options.add_argument('--disable-dev-shm-usage')

    driver = selenium_webdriver.Chrome(options=chrome_options)
    driver.set_window_size(1920, 1080)
    driver.maximize_window()
    driver.implicitly_wait(5)

    yield driver
    driver.quit()

# set up a hook to be able to check if a test has failed
@pytest.hookimpl(tryfirst=True, hookwrapper=True)
def pytest_runtest_makereport(item, call):
    # execute all other hooks to obtain the report object
    outcome = yield
    rep = outcome.get_result()

    # set a report attribute for each phase of a call, which can
    # be "setup", "call", "teardown"

    setattr(item, "rep_" + rep.when, rep)

# check if a test has failed
@pytest.fixture(scope="function", autouse=True)
def test_failed_check(request):
    yield
    # request.node is an "item" because we use the default
    # "function" scope
    if request.node.rep_setup.failed:
        print("setting up a test failed!", request.node.nodeid)
    elif request.node.rep_setup.passed:
        if request.node.rep_call.failed:
            driver = request.node.funcargs['selenium_driver']
            take_screenshot(driver, request.node.nodeid)
            print("executing test failed", request.node.nodeid)

# make a screenshot with a name of the test, date and time
def take_screenshot(driver, nodeid):
    time.sleep(1)
    file_name = f'{nodeid}_{datetime.today().strftime("%Y-%m-%d_%H:%M")}.png'.replace("/","_").replace("::","__")
    driver.save_screenshot(file_name)

Answer 2

还有另一种方法，类似于@Ostap 的方法：使用pytest_runtest_makereport (docs, API reference) 后处理功能。简单一点：

@pytest.hookimpl(tryfirst=True, hookwrapper=True)
def pytest_runtest_makereport(item, call):
    outcome = yield
    rep = outcome.get_result()
    if rep.when == 'call' and rep.failed:
        now = datetime.now().strftime('%Y-%m-%d_%H-%M-%S')
        driver.save_screenshot(f".\\Screenshots\\fail_{now}.png")