在 pytest 中验证来自 SystemExit 的错误代码或消息
Verify the error code or message from SystemExit in pytest
根据 pytest 文档,我可以断言发生了 SystemExit(),但我想做更多:我还想验证退出代码和任何消息。我尝试了下面的代码,但没有打印任何内容,而且我不确定我需要断言什么来证明我得到了正确的错误代码。
with pytest.raises(SystemExit):
docopt_args = validate_args(docopt_args)
out, err = pytest.capsys.readouterr()
assert out == 'Foo'
print out, err
当我 运行 我的测试通过时,仅此而已。没有打印任何内容,我也没有收到断言错误。
我希望执行的代码是:
print '\n' + docopt_args['-d'] + ' is not a valid date\n'
sys.exit(-3)
这适用于最新的 pytest:
您需要做的就是 运行 pytest
使用 --capture=sys
选项并依赖于 raises()
上下文之外的断言(这个位出于某种原因很重要!)
示例:
#!/usr/bin/env python
from __future__ import print_function
import pytest
def f(code=0):
print("Foo")
raise SystemExit(code)
def test_f(capsys):
with pytest.raises(SystemExit):
f()
out, err = capsys.readouterr()
assert out == "Foo\n"
print(out, err)
演示:
$ py.test -v --capture=sys test_foo.py
======================================= test session starts ========================================
platform linux2 -- Python 2.7.9 -- py-1.4.27 -- pytest-2.7.0 -- /home/prologic/.virtualenvs/test/bin/python
rootdir: /home/prologic/tmp, inifile:
collected 1 items
test_foo.py::test_f PASSED
===================================== 1 passed in 0.00 seconds =====================================
将 print("Foo")
更改为 print("Bar")
结果:
$ py.test -v --capture=sys test_foo.py
======================================= test session starts ========================================
platform linux2 -- Python 2.7.9 -- py-1.4.27 -- pytest-2.7.0 -- /home/prologic/.virtualenvs/test/bin/python
rootdir: /home/prologic/tmp, inifile:
collected 1 items
test_foo.py::test_f FAILED
============================================= FAILURES =============================================
______________________________________________ test_f ______________________________________________
capsys = <_pytest.capture.CaptureFixture instance at 0x7f2729405518>
def test_f(capsys):
with pytest.raises(SystemExit):
f()
out, err = capsys.readouterr()
> assert out == "Foo\n"
E assert 'Bar\n' == 'Foo\n'
E - Bar
E + Foo
test_foo.py:17: AssertionError
===================================== 1 failed in 0.01 seconds =====================================
我认为这正是您所追求的!
我干干净净 virtualenv:
mkvirtualenv test
pip install pytest
根据 pytest 文档,我可以断言发生了 SystemExit(),但我想做更多:我还想验证退出代码和任何消息。我尝试了下面的代码,但没有打印任何内容,而且我不确定我需要断言什么来证明我得到了正确的错误代码。
with pytest.raises(SystemExit):
docopt_args = validate_args(docopt_args)
out, err = pytest.capsys.readouterr()
assert out == 'Foo'
print out, err
当我 运行 我的测试通过时,仅此而已。没有打印任何内容,我也没有收到断言错误。
我希望执行的代码是:
print '\n' + docopt_args['-d'] + ' is not a valid date\n'
sys.exit(-3)
这适用于最新的 pytest:
您需要做的就是 运行 pytest
使用 --capture=sys
选项并依赖于 raises()
上下文之外的断言(这个位出于某种原因很重要!)
示例:
#!/usr/bin/env python
from __future__ import print_function
import pytest
def f(code=0):
print("Foo")
raise SystemExit(code)
def test_f(capsys):
with pytest.raises(SystemExit):
f()
out, err = capsys.readouterr()
assert out == "Foo\n"
print(out, err)
演示:
$ py.test -v --capture=sys test_foo.py
======================================= test session starts ========================================
platform linux2 -- Python 2.7.9 -- py-1.4.27 -- pytest-2.7.0 -- /home/prologic/.virtualenvs/test/bin/python
rootdir: /home/prologic/tmp, inifile:
collected 1 items
test_foo.py::test_f PASSED
===================================== 1 passed in 0.00 seconds =====================================
将 print("Foo")
更改为 print("Bar")
结果:
$ py.test -v --capture=sys test_foo.py
======================================= test session starts ========================================
platform linux2 -- Python 2.7.9 -- py-1.4.27 -- pytest-2.7.0 -- /home/prologic/.virtualenvs/test/bin/python
rootdir: /home/prologic/tmp, inifile:
collected 1 items
test_foo.py::test_f FAILED
============================================= FAILURES =============================================
______________________________________________ test_f ______________________________________________
capsys = <_pytest.capture.CaptureFixture instance at 0x7f2729405518>
def test_f(capsys):
with pytest.raises(SystemExit):
f()
out, err = capsys.readouterr()
> assert out == "Foo\n"
E assert 'Bar\n' == 'Foo\n'
E - Bar
E + Foo
test_foo.py:17: AssertionError
===================================== 1 failed in 0.01 seconds =====================================
我认为这正是您所追求的!
我干干净净 virtualenv:
mkvirtualenv test
pip install pytest