如何将 pytest 的结果/日志保存到文件中？

Question

我在尝试将 pytest 显示的所有结果保存到文件（txt、日志、无关紧要）时遇到问题。在下面的测试示例中，我想将控制台中显示的内容捕获到某种文本/日志文件中：

import pytest
import os

def test_func1():
    assert True


def test_func2():
    assert 0 == 1

if __name__ == '__main__':

    pytest.main(args=['-sv', os.path.abspath(__file__)])

我想保存到文本文件的控制台输出：

test-mbp:hi_world ua$ python test_out.py
================================================= test session starts =================================================
platform darwin -- Python 2.7.6 -- py-1.4.28 -- pytest-2.7.1 -- /usr/bin/python
rootdir: /Users/tester/PycharmProjects/hi_world, inifile: 
plugins: capturelog
collected 2 items 

test_out.py::test_func1 PASSED
test_out.py::test_func2 FAILED

====================================================== FAILURES =======================================================
_____________________________________________________ test_func2 ______________________________________________________

    def test_func2():
>       assert 0 == 1
E       assert 0 == 1

test_out.py:9: AssertionError
========================================= 1 failed, 1 passed in 0.01 seconds ==========================================
test-mbp:hi_world ua$ 

Answer 1

看来你所有的测试输出都在stdout，所以你只需要在那里“重定向”你的python调用的输出：

python test_out.py >myoutput.log

您还可以将输出“发送”到多个位置。例如，您可能希望登录到该文件，同时还希望在控制台上查看输出。上面的例子就变成了：

python test_out.py | tee myoutput.log

Answer 2

根据 Bruno Oliveira 的建议，我从 pastebin 得到这个：

#!/usr/bin/env python
# -*- coding: utf-8 -*-

"""
Pytest Plugin that save failure or test session information to a file pass as a command line argument to pytest.

It put in a file exactly what pytest return to the stdout.

To use it :
Put this file in the root of tests/ edit your conftest and insert in the top of the file :

    pytest_plugins = 'pytest_session_to_file'

Then you can launch your test with the new option --session_to_file= like this :

    py.test --session_to_file=FILENAME
Or :
    py.test -p pytest_session_to_file --session_to_file=FILENAME


Inspire by _pytest.pastebin
Ref: https://github.com/pytest-dev/pytest/blob/master/_pytest/pastebin.py

Version : 0.1
Date : 30 sept. 2015 11:25
Copyright (C) 2015 Richard Vézina <ml.richard.vezinar @ gmail.com>
Licence : Public Domain
"""

import pytest
import sys
import tempfile


def pytest_addoption(parser):
    group = parser.getgroup("terminal reporting")
    group._addoption('--session_to_file', action='store', metavar='path', default='pytest_session.txt',
                     help="Save to file the pytest session information")


@pytest.hookimpl(trylast=True)
def pytest_configure(config):
    tr = config.pluginmanager.getplugin('terminalreporter')
    # if no terminal reporter plugin is present, nothing we can do here;
    # this can happen when this function executes in a slave node
    # when using pytest-xdist, for example
    if tr is not None:
        config._pytestsessionfile = tempfile.TemporaryFile('w+')
        oldwrite = tr._tw.write

        def tee_write(s, **kwargs):
            oldwrite(s, **kwargs)
            config._pytestsessionfile.write(str(s))
        tr._tw.write = tee_write


def pytest_unconfigure(config):
    if hasattr(config, '_pytestsessionfile'):
        # get terminal contents and delete file
        config._pytestsessionfile.seek(0)
        sessionlog = config._pytestsessionfile.read()
        config._pytestsessionfile.close()
        del config._pytestsessionfile
        # undo our patching in the terminal reporter
        tr = config.pluginmanager.getplugin('terminalreporter')
        del tr._tw.__dict__['write']
        # write summary  
        create_new_file(config=config, contents=sessionlog)


def create_new_file(config, contents):
    """
    Creates a new file with pytest session contents.
    :contents: paste contents
    :returns: url to the pasted contents
    """
    # import _pytest.config
    # path = _pytest.config.option.session_to_file
    # path = 'pytest_session.txt'
    path = config.option.session_to_file
    with open(path, 'w') as f:
        f.writelines(contents)


def pytest_terminal_summary(terminalreporter):
    import _pytest.config
    tr = terminalreporter
    if 'failed' in tr.stats:
        for rep in terminalreporter.stats.get('failed'):
            try:
                msg = rep.longrepr.reprtraceback.reprentries[-1].reprfileloc
            except AttributeError:
                msg = tr._getfailureheadline(rep)
            tw = _pytest.config.create_terminal_writer(terminalreporter.config, stringio=True)
            rep.toterminal(tw)
            s = tw.stringio.getvalue()
            assert len(s)
            create_new_file(config=_pytest.config, contents=s)

Answer 3

pastebin 内部插件正是这样做的，但将输出直接发送到 bpaste.net。您可以查看插件实现以了解如何根据需要重用它。

Answer 4

这是一个夹具，以便您能够做到这一点，我使用了 pytest 缓存功能，以便利用可以传递给多个测试文件的夹具，包括分布式测试（xdist），以便能够收集和打印测试结果。

conftest.py：

from _pytest.cacheprovider import Cache
from collections import defaultdict

import _pytest.cacheprovider
import pytest

@pytest.hookimpl(tryfirst=True)
def pytest_configure(config):
    config.cache = Cache(config)
    config.cache.set('record_s', defaultdict(list))

@pytest.fixture(autouse=True)
def record(request):
    cache = request.config.cache
    record_s = cache.get('record_s', {})
    testname = request.node.name
    # Tried to avoid the initialization, but it throws errors.
    record_s[testname] = []
    yield record_s[testname]
    cache.set('record_s', record_s)

@pytest.hookimpl(trylast=True)
def pytest_unconfigure(config):
    print("====================================================================\n")
    print("\t\tTerminal Test Report Summary: \n")
    print("====================================================================\n")
    r_cache = config.cache.get('record_s',{})
    print str(r_cache)

用途：

def test_foo(record):
    record.append(('PASS', "reason", { "some": "other_stuff" }))

输出：

====================================================================

        Terminal Test Report Summary:

====================================================================

{u'test_foo': [[u'PASS',u'reason', { u'some': u'other_stuff' } ]]}