Question

unittest.TestCase在Python 2中有一个assertCountEqual method（assertItemsEqual，可以说是一个更好的名字），它比较两个迭代并检查它们是否包含相同数量的相同对象，不顾他们的命令。

pytest是否提供类似的东西？所有明显的替代方案（例如，文档中提到的每侧调用set(x)，sorted(x)或Counter(list(x))）都不起作用，因为我要比较的是字典列表，字典不可用。

Answer 1

pytest不提供assertCountEqual，但我们可以只使用unittest＆＃39>

import unittest def test_stuff(): case = unittest.TestCase() a = [{'a': 1}, {'b': 2}] b = [{'b': 2}] case.assertCountEqual(a, b)

输出也很不错

$ py.test ============================= test session starts ============================== platform linux -- Python 3.6.2, pytest-3.2.1, py-1.4.34, pluggy-0.4.0 rootdir: /home/they4kman/.virtualenvs/tmp-6626234b42fb350/src, inifile: collected 1 item test_stuff.py F =================================== FAILURES =================================== __________________________________ test_stuff __________________________________ def test_stuff(): case = unittest.TestCase() a = [{'a': 1}, {'b': 2}] b = [{'b': 2}] > case.assertCountEqual(a, b) test_stuff.py:7: _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ /usr/lib/python3.6/unittest/case.py:1182: in assertCountEqual self.fail(msg) _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ self = <unittest.case.TestCase testMethod=runTest> msg = "Element counts were not equal:\nFirst has 1, Second has 0: {'a': 1}" def fail(self, msg=None): """Fail immediately, with the given message.""" > raise self.failureException(msg) E AssertionError: Element counts were not equal: E First has 1, Second has 0: {'a': 1} /usr/lib/python3.6/unittest/case.py:670: AssertionError =========================== 1 failed in 0.07 seconds ==========================

附注：the implementation of assertCountEqual包含针对不可用类型的分支具体，does a bunch of bookkeeping and compares each item with every other item。

Answer 2

您可以创建一个适用于大多数情况的通用辅助函数：

def items_equal(xs, ys):
    if isinstance(xs, dict) and isinstance(ys, dict):
        if len(xs) != len(ys):
            return False
        for key in xs.keys():
            try:
                if not items_equal(xs[key], ys[key]):
                    return False
            except KeyError:
                return False
        return True
    elif isinstance(xs, list) and isinstance(ys, list):
        if len(xs) != len(ys):
            return False
        sxs = xs
        sys = ys
        try:
            sxs = sorted(xs)
            sys = sorted(ys)
            for x, y in zip(sxs, sys):
                if not items_equal(x, y):
                    return False
        except TypeError:
            ys_copy = ys.copy()
            for x in xs:
                matches = [i for i, y in enumerate(ys_copy) if items_equal(x, y)]
                if len(matches):
                    del ys_copy[matches[0]]
                    continue
                else:
                    return False
        return True
    else:
        return xs == ys

pytest是否具有assertItemsEqual / assertCountEqual等价物

2 个答案: