缓存：使用交叉测试运行状态¶
使用¶
该插件提供了两个命令行选项，用于从上一个命令行重新运行失败。 pytest 调用：
--lf，--last-failed-只重新运行故障。--ff，--failed-first-先运行失败，然后运行其余的测试。
对于清理（通常不需要），a --cache-clear 选项允许在测试运行之前删除所有跨会话缓存内容。
其他插件可以访问 config.cache 要设置/获取的对象 JSON可编程序 之间的价值 pytest 调用。
注解
此插件在默认情况下是启用的，但在需要时可以禁用：请参阅 按名称停用/注销插件 （此插件的内部名称为 cacheprovider ）
只重新运行失败或失败¶
首先，让我们创建50个测试调用，其中只有2个失败：
# content of test_50.py
import pytest
@pytest.mark.parametrize("i", range(50))
def test_num(i):
if i in (17, 25):
pytest.fail("bad luck")
如果您第一次运行它，您将看到两个失败：
$ pytest -q
.................F.......F........................ [100%]
================================= FAILURES =================================
_______________________________ test_num[17] _______________________________
i = 17
@pytest.mark.parametrize("i", range(50))
def test_num(i):
if i in (17, 25):
> pytest.fail("bad luck")
E Failed: bad luck
test_50.py:7: Failed
_______________________________ test_num[25] _______________________________
i = 25
@pytest.mark.parametrize("i", range(50))
def test_num(i):
if i in (17, 25):
> pytest.fail("bad luck")
E Failed: bad luck
test_50.py:7: Failed
========================= short test summary info ==========================
FAILED test_50.py::test_num[17] - Failed: bad luck
FAILED test_50.py::test_num[25] - Failed: bad luck
2 failed, 48 passed in 0.12s
如果你那么用 --lf ：
$ pytest --lf
=========================== test session starts ============================
platform linux -- Python 3.x.y, pytest-6.x.y, py-1.x.y, pluggy-0.x.y
cachedir: $PYTHON_PREFIX/.pytest_cache
rootdir: $REGENDOC_TMPDIR
collected 2 items
run-last-failure: rerun previous 2 failures
test_50.py FF [100%]
================================= FAILURES =================================
_______________________________ test_num[17] _______________________________
i = 17
@pytest.mark.parametrize("i", range(50))
def test_num(i):
if i in (17, 25):
> pytest.fail("bad luck")
E Failed: bad luck
test_50.py:7: Failed
_______________________________ test_num[25] _______________________________
i = 25
@pytest.mark.parametrize("i", range(50))
def test_num(i):
if i in (17, 25):
> pytest.fail("bad luck")
E Failed: bad luck
test_50.py:7: Failed
========================= short test summary info ==========================
FAILED test_50.py::test_num[17] - Failed: bad luck
FAILED test_50.py::test_num[25] - Failed: bad luck
============================ 2 failed in 0.12s =============================
您只运行了上次运行中的两个失败测试，而48个通过的测试没有运行（“取消选择”）。
现在，如果你和 --ff 选项，将运行所有测试，但将首先执行前面的第一个失败（从 FF 和点）：
$ pytest --ff
=========================== test session starts ============================
platform linux -- Python 3.x.y, pytest-6.x.y, py-1.x.y, pluggy-0.x.y
cachedir: $PYTHON_PREFIX/.pytest_cache
rootdir: $REGENDOC_TMPDIR
collected 50 items
run-last-failure: rerun previous 2 failures first
test_50.py FF................................................ [100%]
================================= FAILURES =================================
_______________________________ test_num[17] _______________________________
i = 17
@pytest.mark.parametrize("i", range(50))
def test_num(i):
if i in (17, 25):
> pytest.fail("bad luck")
E Failed: bad luck
test_50.py:7: Failed
_______________________________ test_num[25] _______________________________
i = 25
@pytest.mark.parametrize("i", range(50))
def test_num(i):
if i in (17, 25):
> pytest.fail("bad luck")
E Failed: bad luck
test_50.py:7: Failed
========================= short test summary info ==========================
FAILED test_50.py::test_num[17] - Failed: bad luck
FAILED test_50.py::test_num[25] - Failed: bad luck
======================= 2 failed, 48 passed in 0.12s =======================
新的 --nf ， --new-first 选项：首先运行新的测试，然后运行其余的测试，在这两种情况下，测试也按文件修改时间排序，最新的文件排在第一位。
上次运行中没有测试失败时的行为¶
上次运行中没有测试失败，或没有缓存时 lastfailed 数据被发现， pytest 可以配置为运行所有测试或不运行任何测试，使用 --last-failed-no-failures 选项，它采用以下值之一：
pytest --last-failed --last-failed-no-failures all # run all tests (default behavior)
pytest --last-failed --last-failed-no-failures none # run no tests and exit
新的config.cache对象¶
插件或conftest.py支持代码可以使用pytest获取缓存值。 config 对象。下面是一个实现 fixture 它跨pytest调用重用先前创建的状态：
# content of test_caching.py
import pytest
import time
def expensive_computation():
print("running expensive computation...")
@pytest.fixture
def mydata(request):
val = request.config.cache.get("example/value", None)
if val is None:
expensive_computation()
val = 42
request.config.cache.set("example/value", val)
return val
def test_function(mydata):
assert mydata == 23
如果第一次运行此命令，则可以看到print语句：
$ pytest -q
F [100%]
================================= FAILURES =================================
______________________________ test_function _______________________________
mydata = 42
def test_function(mydata):
> assert mydata == 23
E assert 42 == 23
test_caching.py:20: AssertionError
-------------------------- Captured stdout setup ---------------------------
running expensive computation...
========================= short test summary info ==========================
FAILED test_caching.py::test_function - assert 42 == 23
1 failed in 0.12s
如果再次运行该值，将从缓存中检索该值，并且不会打印任何内容：
$ pytest -q
F [100%]
================================= FAILURES =================================
______________________________ test_function _______________________________
mydata = 42
def test_function(mydata):
> assert mydata == 23
E assert 42 == 23
test_caching.py:20: AssertionError
========================= short test summary info ==========================
FAILED test_caching.py::test_function - assert 42 == 23
1 failed in 0.12s
见 config.cache fixture 了解更多详细信息。
正在检查缓存内容¶
您可以使用 --cache-show 命令行选项：
$ pytest --cache-show
=========================== test session starts ============================
platform linux -- Python 3.x.y, pytest-6.x.y, py-1.x.y, pluggy-0.x.y
cachedir: $PYTHON_PREFIX/.pytest_cache
rootdir: $REGENDOC_TMPDIR
cachedir: $PYTHON_PREFIX/.pytest_cache
--------------------------- cache values for '*' ---------------------------
cache/lastfailed contains:
{'test_50.py::test_num[17]': True,
'test_50.py::test_num[25]': True,
'test_assert1.py::test_function': True,
'test_assert2.py::test_set_comparison': True,
'test_caching.py::test_function': True,
'test_foocompare.py::test_compare': True}
cache/nodeids contains:
['test_50.py::test_num[0]',
'test_50.py::test_num[10]',
'test_50.py::test_num[11]',
'test_50.py::test_num[12]',
'test_50.py::test_num[13]',
'test_50.py::test_num[14]',
'test_50.py::test_num[15]',
'test_50.py::test_num[16]',
'test_50.py::test_num[17]',
'test_50.py::test_num[18]',
'test_50.py::test_num[19]',
'test_50.py::test_num[1]',
'test_50.py::test_num[20]',
'test_50.py::test_num[21]',
'test_50.py::test_num[22]',
'test_50.py::test_num[23]',
'test_50.py::test_num[24]',
'test_50.py::test_num[25]',
'test_50.py::test_num[26]',
'test_50.py::test_num[27]',
'test_50.py::test_num[28]',
'test_50.py::test_num[29]',
'test_50.py::test_num[2]',
'test_50.py::test_num[30]',
'test_50.py::test_num[31]',
'test_50.py::test_num[32]',
'test_50.py::test_num[33]',
'test_50.py::test_num[34]',
'test_50.py::test_num[35]',
'test_50.py::test_num[36]',
'test_50.py::test_num[37]',
'test_50.py::test_num[38]',
'test_50.py::test_num[39]',
'test_50.py::test_num[3]',
'test_50.py::test_num[40]',
'test_50.py::test_num[41]',
'test_50.py::test_num[42]',
'test_50.py::test_num[43]',
'test_50.py::test_num[44]',
'test_50.py::test_num[45]',
'test_50.py::test_num[46]',
'test_50.py::test_num[47]',
'test_50.py::test_num[48]',
'test_50.py::test_num[49]',
'test_50.py::test_num[4]',
'test_50.py::test_num[5]',
'test_50.py::test_num[6]',
'test_50.py::test_num[7]',
'test_50.py::test_num[8]',
'test_50.py::test_num[9]',
'test_assert1.py::test_function',
'test_assert2.py::test_set_comparison',
'test_caching.py::test_function',
'test_foocompare.py::test_compare']
cache/stepwise contains:
[]
example/value contains:
42
========================== no tests ran in 0.12s ===========================
--cache-show 采用可选参数指定用于筛选的全局模式：
$ pytest --cache-show example/*
=========================== test session starts ============================
platform linux -- Python 3.x.y, pytest-6.x.y, py-1.x.y, pluggy-0.x.y
cachedir: $PYTHON_PREFIX/.pytest_cache
rootdir: $REGENDOC_TMPDIR
cachedir: $PYTHON_PREFIX/.pytest_cache
----------------------- cache values for 'example/*' -----------------------
example/value contains:
42
========================== no tests ran in 0.12s ===========================
逐步的¶
作为替代 --lf -x 尤其是在您期望测试套件的大部分将失败的情况下， --sw ， --stepwise 允许您一次修复一个。测试套件将运行到第一次失败，然后停止。在下一次调用时，测试将从上次失败的测试继续进行，然后运行到下一次失败的测试。你可以使用 --stepwise-skip 选项忽略一个失败的测试并停止对第二个失败的测试的执行。如果你在一个失败的测试中陷入困境，并且只想在稍后忽略它，那么这很有用。
