python - 使用补丁添加 OverflowError 副作用 - Python

Question

我想模拟一个 OverflowError 因为我想在引发异常之后测试变量的值。但是，我不知道如何使用我正在使用的库复制 OverflowError。我在此特定测试中使用的库是 pysolar.solar，特别是 get_altitude、get_azimuth 和 辐射方法p>

在无意识地尝试不同的数字来尝试模拟 OverflowError 后，我决定尝试模拟该函数并引入副作用。

我正在测试的代码 sunposition.py

import numpy as np
import pandas as pd
from pysolar.solar import get_altitude, get_azimuth, radiation as radiation_module


def sun_position(lat: float, lon: float, time: pd.Timestamp = None) -> List[float]:

    if time is None:
    time = pd.Timestamp.now(tz='UTC')

    dt = time.to_pydatetime()

    altitude = get_altitude(lat, lon, dt)
    azimuth = get_azimuth(lat, lon, dt)

    try:
        radiation = radiation_module.get_radiation_direct(dt, altitude)
    except OverflowError:
        radiation = np.nan

    return pd.Series([altitude, azimuth, radiation], index=['Alt', 'Azi', 'Rad'])

**我开始用补丁做什么**

"""Test sunposition module"""
import unittest
import numpy as np
import pandas as pd
from unittest.mock import MagicMock, patch, Mock

from bigfolder.sun import sunposition


class TestSunposition(unittest.TestCase):
"""Test functions in sunposition."""


def test_sun_position_overflow_error(self):

    error_lat = 23
    error_lon = 12
    error_time = pd.Timestamp('2007-02-18 15:13:05', tz="UTC")

    mock_args = {'side_effect': OverflowError}
    with patch('bigfolder.sun.sunposition.sun_position', **mock_args):
        # run the test

        self.assertRaises(OverflowError,  sunposition.sun_position(lat=error_lat, lon=error_lon, time=error_time))


if __name__ == '__main__':
    unittest.main()

我原以为它会给我带来 OverFlow 错误...而且确实如此，但是我的断言无论如何都失败了，并出现 OverflowError 我的猜测是我在错误的位置进行了修补？我真的不明白为什么测试失败，无论错误仍然是 OverFlow Error

这是打印出来的

_mock_self = <MagicMock name='sun_position' id='102333856'>, args = ()
kwargs = {'lat': 23, 'lon': 12, 'time': Timestamp('2007-02-18 15:13:05+0000', tz='UTC')}
self = <MagicMock name='sun_position' id='102333856'>, _new_name = ''
_new_parent = None
_call = call(lat=23, lon=12, time=Timestamp('2007-02-18 15:13:05+0000', tz='UTC'))
seen = set(), skip_next_dot = False, do_method_calls = False
name = 'sun_position'

    def _mock_call(_mock_self, *args, **kwargs):
        self = _mock_self
        self.called = True
        self.call_count += 1
        _new_name = self._mock_new_name
        _new_parent = self._mock_new_parent

        _call = _Call((args, kwargs), two=True)
        self.call_args = _call
        self.call_args_list.append(_call)
        self.mock_calls.append(_Call(('', args, kwargs)))

        seen = set()
        skip_next_dot = _new_name == '()'
        do_method_calls = self._mock_parent is not None
        name = self._mock_name
        while _new_parent is not None:
            this_mock_call = _Call((_new_name, args, kwargs))
            if _new_parent._mock_new_name:
                dot = '.'
                if skip_next_dot:
                    dot = ''

                skip_next_dot = False
                if _new_parent._mock_new_name == '()':
                    skip_next_dot = True

                _new_name = _new_parent._mock_new_name + dot + _new_name

            if do_method_calls:
                if _new_name == name:
                    this_method_call = this_mock_call
                else:
                    this_method_call = _Call((name, args, kwargs))
                _new_parent.method_calls.append(this_method_call)

                do_method_calls = _new_parent._mock_parent is not None
                if do_method_calls:
                    name = _new_parent._mock_name + '.' + name

            _new_parent.mock_calls.append(this_mock_call)
            _new_parent = _new_parent._mock_new_parent

            # use ids here so as not to call __hash__ on the mocks
            _new_parent_id = id(_new_parent)
            if _new_parent_id in seen:
                break
            seen.add(_new_parent_id)

        ret_val = DEFAULT
        effect = self.side_effect
        if effect is not None:
            if _is_exception(effect):
>               raise effect
E               OverflowError

所以我想我一定是在错误的地方打了补丁并且比我应该的更早引入了副作用？所以我改为将方法修补到 try block 中。 这是我的以下代码。

def test_sun_position_overflow_error(self):

    error_lat = 23
    error_lon = 12
    error_time = pd.Timestamp('2007-02-18 15:13:05', tz="UTC")

    mock_args = {'side_effect': OverflowError}
    with patch('bigfolder.sun.sunposition.sun_position.radiation_module.get_radiation_direct', **mock_args):
    # run the test

    self.assertRaises(OverflowError,  sunposition.sun_position(lat=error_lat, lon=error_lon, time=error_time))

现在我的错误是“ModuleNotFoundError:没有名为 'bigfolder.sun.sunposition.sun_position' 的模块；'bigfolder.sun.sunposition' 不是一个包”

然后我只是将路径更改为'sun_position.radiation_module.get_radiation_direct'，但没有找到模块。

所以我的问题是:如何复制 OverflowError，以便在引发异常后我可以检查我设置的变量的值。为什么我引入的第一个 OverflowError 仍然没有通过我的断言？

谢谢

更新测试通过

按照@Gang的建议后，OverFlowError被重现。我意识到，为了测试该 block 的异常，特别是 radiation 是 np.nan，我必须修补我想要的方法 有 OverFlowError 而不是 sun_position 的整个方法。当我尝试这样做时，我错误地导入了它，因为我认为外部库是代码的一部分。因此，我将 bigfolder.sun.sunposition.sun_position.radiation_module.get_radiation_direct 更改为 pysolar.solar.radiation.get_radiation_direct ，这是具有我想要模拟的 get_radiation_direct 方法的外部库。

def test_sun_position_overflow_error(self):
    lat = 23
    lon = 12
    time = pd.Timestamp('2007-02-18 15:13:05', tz="UTC")

    # get_radiation_direct will now produce an OverFlowError(regardless of coordinates)
    mock_args = {'side_effect': OverflowError}
    # mock get_radiation_direct and produce OverFlowError
    with patch('pysolar.solar.radiation.get_radiation_direct', **mock_args):
        # Check radiation column is nan value
        assert math.isnan(sunposition.sun_position(lat=lat, lon=lon, time=time)[2])

Answer 1

Why is the first OverflowError I introduce still not pass my assertion?

快到了。 assertRaises 的正确方法:

def test_sun_position_overflow_error(self):
    # This has to be here first and without func call
    with self.assertRaises(OverflowError):
        # patch the function to have an exception no matter what
        mock_args = {'side_effect': OverflowError}
        with patch('bigfolder.sun.sunposition.sun_position', **mock_args):
            # call this func to trigger an exception
            sunposition.sun_position(lat=error_lat, lon=error_lon, time=error_time)

查看文档后，是如何在assertRaises中调用func

assertRaises(exception, callable, *args, **kwds)

fun(*args, **kwds) raises exc

这种用法是错误的:

self.assertRaises(OverflowError,  sunposition.sun_position(lat=error_lat, lon=error_lon, time=error_time))

它应该是一个带有 kwargs 的函数名称:

self.assertRaises(OverflowError,  sunposition.sun_position, lat=error_lat, lon=error_lon, time=error_time)