pandas - 在单元测试中创建 Pandas 数据框

Question

在我的单元测试文件中尝试创建 Pandas 数据框时，我遇到了一个我不明白的问题。该错误发生在类中的函数被调用之前。

这里是一个简单的重现代码:

import unittest
import pandas as pd
import numpy as np

class simpleTest(unitest.TestCase):
    dates = pd.date_range('20160101', periods = 5)
    dataDf = pd.DataFrame({'date': dates,
            'count': np.array([3, 7, 4, 66, 9])})

    def doSomething(self):
        pass

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

我得到的错误是这样的:

Traceback (most recent call last):
  File "tsa_test.py", line 31, in <module>
    unittest.main()
  File "/usr/local/Cellar/python/2.7.12/Frameworks/Python.framework/Versions/2.7/lib/python2.7/unittest/main.py", line 94, in __init__
    self.parseArgs(argv)
  File "/usr/local/Cellar/python/2.7.12/Frameworks/Python.framework/Versions/2.7/lib/python2.7/unittest/main.py", line 149, in parseArgs
    self.createTests()
  File "/usr/local/Cellar/python/2.7.12/Frameworks/Python.framework/Versions/2.7/lib/python2.7/unittest/main.py", line 158, in createTests
    self.module)
  File "/usr/local/Cellar/python/2.7.12/Frameworks/Python.framework/Versions/2.7/lib/python2.7/unittest/loader.py", line 130, in loadTestsFromNames
    suites = [self.loadTestsFromName(name, module) for name in names]
  File "/usr/local/Cellar/python/2.7.12/Frameworks/Python.framework/Versions/2.7/lib/python2.7/unittest/loader.py", line 100, in loadTestsFromName
    parent, obj = obj, getattr(obj, part)
AttributeError: 'module' object has no attribute '-'

Answer 1

您的单元测试代码有问题。您在子类化 unittest.TestCase 方面做对了，所以这一行没问题:

class simpleTest(unitest.TestCase):

但是，这个类现在应该有如下所示的方法:

     def test_foo(self):
         ...

(注意它们应该以 test_ 开头，并且应该以 self 开头)。遗漏任何此类方法都会混淆单元测试。

另外，您有静态类成员，您可能打算将其用作类固定装置。那是 not how it's done in unittest .你的类应该是这样的:

class simpleTest(unitest.TestCase):
    @classmethod
    def setUpClass(cls):
        cls.dates = pd.date_range('20160101', periods = 5)
        cls.dataDf = pd.DataFrame({'date': cls.dates,
            'count': np.array([3, 7, 4, 66, 9])})

    def test_foo(self):
        # Note that here you access things like so:
        self.dataDF
        # even though you defined it as a class instance - that's how unittest works