[英]AssertionError when using nosetests
在学习Python困难之路的练习48中,我被要求创建一个要由此测试的模块lexicon_tests.py
:
from nose.tools import *
from ex48 import lexicon
def test_directions():
assert_equal(lexicon.scan("north"), [('direction', 'north')])
result = lexicon.scan("north south east")
assert_equal(result, [('direction', 'north'),
('direction', 'south'),
('direction', 'east')])
def test_verbs():
assert_equal(lexicon.scan("go"), [('verb', 'go')])
result = lexicon.scan("go kill eat")
assert_equal(result, [('verb', 'go'),
('verb', 'kill'),
('verb', 'eat')])
def test_stops():
assert_equal(lexicon.scan("the"), [('stop', 'the')])
result = lexicon.scan("the in of")
assert_equal(result, [('stop', 'the'),
('stop', 'in'),
('stop', 'of')])
def test_nouns():
assert_equal(lexicon.scan("bear"), [('noun', 'bear')])
result = lexicon.scan("bear princess")
assert_equal(result, [('noun', 'bear'),
('noun', 'princess')])
def test_numbers():
assert_equal(lexicon.scan("1234"), [('number', 1234)])
result = lexicon.scan("3 91234")
assert_equal(result, [('number', 3),
('number', 91234)])
def test_errors():
assert_equal(lexicon.scan("ASDFADFASDF"), [('error', 'ASDFADFASDF')])
result = lexicon.scan("bear IAS princess")
assert_equal(result, [('noun', 'bear'),
('error', 'IAS'),
('noun', 'princess')])
所以我在这里创建了要测试的模块lexicon.py
:
def scan(words):
directions = ['north', 'south', 'east', 'west', 'down', 'up', 'left', 'right', 'back']
verbs = ['go', 'stop', 'kill', 'eat']
stop_words = ['the', 'in', 'of', 'from', 'at', 'it']
nouns = ['door', 'bear', 'princess', 'cabinet']
lex = words.split()
list1 = []
for i in lex:
if i in directions:
list1.append(('direction', i))
elif i in verbs:
list1.append(('verb', i))
elif i in stop_words:
list1.append(('stop-word', i))
elif i in nouns:
list1.append(('noun', i))
elif i.isdigit():
list1.append(('number', convert_number(i)))
else:
list1.append(('error', i))
print list1
def convert_number(s):
try:
return int(s)
except ValueError:
return None
但是当我在powershell中运行nosetests
,我得到了这个AssertionError:
Traceback (most recent call last):
File "G:\Python27\lib\site-packages\nose\case.py", line 197, in runTest
self.test(*self.arg)
File "G:\Users\Charles\dropbox\programming\lexicon_test\skeleton\tests\lexicon_tests.py", line 6, in test_directions
assert_equal(lexicon.scan("north"), [('direction', 'north')])
AssertionError: None != [('direction', 'north')]
-------------------- >> begin captured stdout << ---------------------
[('direction', 'north')]
这是我为每次测试运行得到的相同错误消息,其中六个用于lexicon_tests.py
的六个函数。 这个错误是什么意思? 一段时间以来一直很烦人。 提前致谢。
assert_equal
函数接受两个参数,如果参数彼此不相等则抛出错误。 在这种情况下, lexicon.scan("north")
为None
,并且因为它不等于[('direction', 'north')]
,所以它会抛出错误。
换句话说,您的lexicon.scan
功能无法正常工作。 它可能与它缺少一个return
语句有关。
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