Les Tests De Scripts Python

Python propre suite de tests ne un peu les choses, et nous utilisons deux techniques principales:

1. Rediriger stdout (comme d'autres l'ont suggéré). Nous utilisons un gestionnaire de contexte pour ce:

   import io
   import sys
   import contextlib
   
   @contextlib.contextmanager
   def captured_output(stream_name):
       """Run the 'with' statement body using a StringIO object in place of a
          specific attribute on the sys module.
          Example use (with 'stream_name=stdout'):
   
          with captured_stdout() as s:
              print("hello")
              assert s.getvalue() == "hello"
       """
       orig_stdout = getattr(sys, stream_name)
       setattr(sys, stream_name, io.StringIO())
       try:
           yield getattr(sys, stream_name)
       finally:
           setattr(sys, stream_name, orig_stdout)
   
   def captured_stdout():
       return captured_output("stdout")
   
   def captured_stderr():
       return captured_output("stderr")
   
   def captured_stdin():
       return captured_output("stdin")

2. À l'aide de la subprocess module. Nous utilisons quand nous voulons tester la manipulation des arguments de ligne de commande. Voir http://hg.python.org/cpython/file/default/Lib/test/test_cmd_line_script.py pour plusieurs exemples.

OriginalL'auteur ncoghlan

Ici est quelque chose que j'ai écrit, un soir, que les tests de script s'exécute. Notez que le test ne couvre pas la base de cas, mais il n'est pas assez approfondie pour être un unittest par lui-même. Considérez que c'est un premier projet.

import sys
import subprocess

if sys.platform == "win32":
   cmd = "zs.py"
else:
   cmd = "./zs.py"

def testrun(cmdline):
   try:
      retcode = subprocess.call(cmdline, shell=True)
      if retcode < 0:
         print >>sys.stderr, "Child was terminated by signal", -retcode
      else:
         return retcode
   except OSError, e:
      return e

tests = []
tests.append( (0, " string pattern 4") )
tests.append( (1, " string pattern") )
tests.append( (3, " string pattern notanumber") )
passed = 0

for t in tests:
   r = testrun(cmd + t[1])
   if r == t[0]:
      res = "passed"
      passed += 1
   else:
      res = "FAILED"
   print res, r, t[1]

print
if passed != len(tests):
   print "only",passed,"tests passed"
else:
   print "all tests passed"

Et voici le script qui a été testé, zs.py Ce n'modèle de recherche dans une chaîne similaire à la façon dont les biochimistes rechercher des modèles dans les données ADN ou de protéines de données de la chaîne.

#!/usr/bin/env python
# zs - some example Python code to demonstrate to Z??s
#      interviewers that the writer really does know Python
import sys
from itertools import *
usage = '''
Usage: zs <string> <pattern> <n>"
print top n matches of pattern in substring"
'''
if sys.hexversion > 0x03000000:
print "This script is only intended to run on Python version 2"
sys.exit(2)
if len(sys.argv) != 4:
print usage
sys.exit(1)
A = sys.argv[1] # string to be searched
B = sys.argv[2] # pattern being searched for
N = sys.argv[3] # number of matches to report
if not N.isdigit():
print "<n> must be a number"
print usage
sys.exit(3)
def matchscore(s1, s2):
''' a helper function to calculate the match score
'''
matches = 0
for i in xrange(len(s1)):
if s1[i] == s2[i]:
matches += 1
return (matches + 0.0) / len(s1)  # added 0.0 to force floating point div
def slices(s, n):
''' this is a generator that returns the sequence of slices of
the input string s that are n characters long '''
slen = len(s)
for i in xrange(slen - n + 1):
yield s[i:i+n]
matchlen = len(B)
allscores = ((matchscore(x,B),x,i) for i,x in enumerate(slices(A,matchlen)))
nonzeros = [ y for y in allscores if y[0] != 0 ]
for elem in sorted(nonzeros,key=lambda e: e[0],reverse=True):
nprinted = 0 # We will count them; in case num elements > N
print elem[1], str(round(elem[0],4)), elem[2]
nprinted += 1
if nprinted >= N:
break

OriginalL'auteur Michael Dillon