我一直在尝试编写一个测试(使用unittest)来测试函数的输出。
该函数如下:
def main():
arg_pressent = len(sys.argv)
if arg_pressent < 2:
print "usage: ./pyPeerChat [IP ADDRESS of pc] / [0 (if the network is not known. This will assume that this peer will be the start of a new network)]"
else:
IP = str(sys.argv[1])
connect.main(IP)
if __name__ == '__main__':
main()
因此,我的测试需要测试以下事实:当此函数单独运行(不传递任何参数)时,它会打印'用法:./pyPeerChat [pc的IP地址] / [0(如果网络未知)这将假定此对等点将是新网络的开始)]'。
到目前为止,我目前正在尝试实施的测试是:
import myModuleChat
from io import StringIO
import unittest
from mock import patch
def main():
Testmain.test_main_prints_without_ARGs()
class TestMain(unittest.TestCase):
def test_main_prints_without_ARGs(self):
expected_print = 'usage: ./pyPeerChat [IP ADDRESS of Bootpeer] / [0 (if the network is not known. This will assume that this peer will be the #start of a new network)]'
with patch('sys.stdout', new=StringIO()) as fake_out:
pyPeerChat.main()
self.assertEqual(fake_out.getvalue(), expected_print)
if __name__ == '__main__':
test_program = unittest.main(verbosity=0, buffer=False, exit=False)
但是,我无法使该测试成功通过。测试失败,并且出现错误。以下是测试的全部输出,但有错误:
======================================================================
ERROR: test_main_prints_without_ARGs (__main__.TestMain)
----------------------------------------------------------------------
Traceback (most recent call last):
File "testpyPeerChat.py", line 24, in test_main_prints_without_ARGs
pyPeerChat.main()
File "/home/peer-node/Testing/P2PChat/source/pyPeerChat.py", line 47, in main
print "usage: ./pyPeerChat [IP ADDRESS of Bootpeer] / [0 (if the network is not known. This will assume that this peer will be the start of a new network)]"
TypeError: unicode argument expected, got 'str'
----------------------------------------------------------------------
Ran 1 test in 0.000s
FAILED (errors=1)
我完全不确定这个错误是什么意思,因为代码可以正常工作。有没有更简单的方法编写我需要的测试,或者是修复测试的方法?
最佳答案
好的,因此,在进行更多搜索之后,我确定了如何将标准输出从函数绑定到变量。然后,使用assertEqual(),我可以将其与“期望的”字符串进行比较:
from pyPeerChat import main
from StringIO import StringIO
import unittest
class TestFoo(unittest.TestCase):
def test_output_without_args(self):
out = StringIO()
main(out=out)
output = out.getvalue().strip()
expected = 'usage: ./pyPeerChat [IP ADDRESS of Bootpeer] / [0 (if the network is not known. This will assume that this peer will be the start of a new network)]'
self.assertEqual(output, expected)
if __name__ == '__main__':
unittest.main()
#'usage: ./pyPeerChat [IP ADDRESS of Bootpeer] / [0 (if the network is not known. This will assume that this peer will be the start of a new network)]'
这使我成功通过了测试。