我正在讲授使用Python进行编程课程的介绍。我正在使用py.test来为学生的作业评分。我有一种情况,当测试函数是一个顺序时,py.test报告失败的测试用例,但是当测试函数以另一种顺序时,报告通过。py.test函数的排序导致失败
我创建了一个带有失败程序和测试代码的project on Github。但这里是测试程序的摘录。
from exercise3 import union, intersection, difference
###########
# TABLES ##
###########
GRADUATES = [["Number", "Surname", "Age"],
[7274, "Robinson", 37],
[7432, "O'Malley", 39],
[9824, "Darkes", 38]]
MANAGERS = [["Number", "Surname", "Age"],
[9297, "O'Malley", 56],
[7432, "O'Malley", 39],
[9824, "Darkes", 38]]
#####################
# HELPER FUNCTIONS ##
#####################
def is_equal(t1, t2):
return sorted(t1) == sorted(t2)
###################
# TEST FUNCTIONS ##
###################
def test_union():
"""
Test union operation.
"""
result = [["Number", "Surname", "Age"],
[7274, "Robinson", 37],
[9297, "O'Malley", 56],
[7432, "O'Malley", 39],
[9824, "Darkes", 38]]
assert is_equal(result, union(GRADUATES, MANAGERS))
def test_intersection():
"""
Test intersection operation.
"""
result = [["Number", "Surname", "Age"],
[7432, "O'Malley", 39],
[9824, "Darkes", 38]]
assert is_equal(intersection(GRADUATES, MANAGERS), result)
如果我把test_union函数放在第一位,而test_intersection函数第二位,后者失败。这里是py.test的输出。它看起来像test_intersection中的结果变量正在使用test_union函数中的值。
/Users/ses/anaconda/bin/python "/Applications/PyCharm Educational.app/Contents/helpers/pycharm/pytestrunner.py" -p pytest_teamcity /Users/ses/PycharmProjects/pytest_weirdness/test_exercise3.py
Testing started at 1:11 PM ...
============================= test session starts ==============================
platform darwin -- Python 2.7.10 -- py-1.4.27 -- pytest-2.7.1
rootdir: /Users/ses/PycharmProjects/pytest_weirdness, inifile:
collected 3 items
../../../../Users/ses/PycharmProjects/pytest_weirdness/test_exercise3.py .F
def test_intersection():
"""
Test intersection operation.
"""
result = [["Number", "Surname", "Age"],
[7432, "O'Malley", 39],
[9824, "Darkes", 38]]
> assert is_equal(intersection(GRADUATES, MANAGERS), result)
E assert is_equal([['Number', 'Surname', 'Age'], [7432, "O'Malley", 39], [9824, 'Darkes', 38], [9297, "O'Malley", 56]], [['Number', 'Surname', 'Age'], [7432, "O'Malley", 39], [9824, 'Darkes', 38]])
E + where [['Number', 'Surname', 'Age'], [7432, "O'Malley", 39], [9824, 'Darkes', 38], [9297, "O'Malley", 56]] = intersection([['Number', 'Surname', 'Age'], [7274, 'Robinson', 37], [7432, "O'Malley", 39], [9824, 'Darkes', 38], [9297, "O'Malley", 56]], [['Number', 'Surname', 'Age'], [9297, "O'Malley", 56], [7432, "O'Malley", 39], [9824, 'Darkes', 38]])
如果我颠倒了顺序,两个测试都通过了。如果我一次运行一个测试,测试用例就会通过。
这对我来说很混乱,因为我认为测试用例的顺序并不重要。另外,我自己的代码没有问题。这项任务直到今晚才到期,所以我还没有分享解决方案,但the original repo is also available on GitHub。
我使用蟒蛇2.3.0分布和PyCharm教育版与Python 2.7.10和pytest-2.7.1
如果他们的'union'或'intersection'函数实际上改变了'GRADUTES'或'MANAGERS'的值,那么调用第二个测试用例可能会失败,因为预期的结果是不正确的。 –
但是Python不按值调用?此外,我已经打印出表格的内容,并且它们看起来很好。奇怪的是结果表是不正确的。我会将错误消息添加到帖子中。 – benevolentprof
取决于你传入的是什么类型。因为'lists'在技术上是可变的,所以你可以用'list.sort()''' –