习题47：自动化测试
通过测试代码简化测试过程
被测试的代码
class Room(object):
def __init__(self, name, description):
self.name = name
self.description = description
self.paths = {}
def go(self, direction):
return self.paths.get(direction, None)
def add_paths(self, paths):
self.paths.update(paths)测试代码
from nose.tools import *
from DataMining.BFF27_52 import Room
def test_room():
gold = Room("GoldRoom",
"""This room has gold in it you can grad.
There's a door to the north.
""") # 测试__init__那个函数，需要输入name和
assert_equal(gold.name, "GoldRoom")
assert_equal(gold.paths, {})
def test_room_paths():
center = Room("Center", "Test room in the center.")
north = Room("North", "Test room in the nroth.")
south = Room("South", "Test room in the south.")
center.add_paths({'north': north, 'south': south})
assert_equal(center.go('north'), north) # 走north就到了north
assert_equal(center.go('south'), south)
def test_map():
start = Room("Start", "You can go west and down a hole.")
west = Room("Trees", "There are trees here, you can go east.")
down = Room("Dungeon", "It's dark down here, you can go up.")
start.add_paths({'west': west, 'down': down})
west.add_paths({'east': start})
down.add_path({'up': start})
assert_equal(start.go('west'), west)
assert_equal(start.go('west').go('east'), start) # 回到原点
assert_equal(start.go('down').go('up'), start)
有个错，add_paths少写了一个s，加上之后（给的代码里每加）
其实吧，我并没怎么看懂这个测试代码，解释说创建一些小房间，测试基本的房间功能，然后测试了路径，最后测试了整个地图。
尤其assert_equal，书上说它保证了你设置的变量，以及在Room里设置的路径和你的期望相符。
常用于测试代码，用于判断两个值是否相等，不等抛出异常。
习题48：更复杂的用户输入
前面要求用户输入完全正确后才能执行，这里希望用户的输入和常用英语很接近也应该可以。所以建立相关模组实现。
作者在游戏里创建了下面这些语汇：
表示方向: north, south, east, west, down, up, left, right, back.
动词: go, stop, kill, eat.
修饰词: the, in, of, from, at, it
名词: door, bear, princess, cabinet.
数词: 由 0-9 构成的数字.
什么是异常？
异常是运行某个函数时得到的一个错误，函数在碰到错误时会提出一个异常。
处理异常的方法是使用try和except两个关键字
给出测试代码，自己写程序
from nose.tools import *
from DataMining.BFF27_52 import lexicon
def test_direction():
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_noun():
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("ASDFAFASDF"), [('error', 'ASDFAFASDF')])
result = lexicon.scan("bear IAS princess")
assert_equal(result, [('noun', 'bear'),
('error', 'IAS'),
('noun', 'princess')])
被测试代码（参考 笨方法学python Lesson 46 - 49 ）
class Lexicon(object):
def scan(self, stuff):
self.stuff = stuff
words = stuff.split() # 对句子进行分割
sentence = []
for i in words:
try:
sentence.append(('number', int(i)))
except ValueError:
if i in ['north', 'south', 'east', 'west', 'down', 'up', 'left', 'right', 'back']:
sentence.append(('direction', i))
elif i in ['go', 'stop', 'kill', 'eat']:
sentence.append(('verb', i))
elif i in ['the', 'in', 'of', 'from', 'at', 'in']:
sentence.append(('stop', i))
elif i in ['door', 'bear', 'princess', 'cabinet']:
sentence.append(('noun', i))
else:
sentence.append(('error', i))
return sentence
lexicon = Lexicon()
虽然理解了，但是根据测试代码写出源代码还是有点困难。
习题49：创建句子
# 在上一习题的基础上
print(lexicon.scan("go north"))
print(lexicon.scan("kill the princess"))
print(lexicon.scan("eat the bear"))
print(lexicon.scan("open the door and smack the bear in the nose"))
匹配（Match）和窥视（Peek）
为了达到这个效果，你需要四样工具：
1. 循环访问元组列表的方法，这挺简单的。
2. 匹配我们的主谓宾设置中不同种类元组的方法。
3. 一个“窥视”潜在元组的方法，以便做决定时用到。
4. 跳过(skip)我们不在乎的内容的方法，例如形容词、冠词等没有用处的词汇。
被测试代码（书上给出的源代码）
class ParserError(Exception):
pass
class Sentence(object):
def __init__(self, subject, verb, object):
self.subject = subject[1]
self.verb = verb[1]
self.object = object[1]
def peek(word_list): # 查看元组列表中的下一个成员，做匹配以后再对它做下一步动作
if word_list:
word = word_list[0]
return word[0]
else:
return None
def match(word_list, expecting):
if word_list:
word = word_list.pop(0)
if word[0] == expecting
return word
else:
return None
else:
return None
def skip(word_list, word_type):
while peek(word_list) == word_type:
match(word_list, word_type)
def parse_verb(word_list):
skip(word_list, 'stop')
if peek(word_list) == 'verb':
return match(word_list, 'verb')
else:
raise ParserError("Expected a verb next.")
def parse_object(word_list):
skip(word_list, 'stop')
nexta = peek(word_list)
if nexta == 'noun':
return match(word_list, 'noun')
if nexta == 'direction':
return match(word_list, 'direction')
else:
raise ParserError("expected a moun or direction next.")
def parse_subject(word_list, subj):
verb = parse_verb(word_list)
obj = parse_object(word_list)
return Sentence(subj, verb, obj)
def parse_sentence(word_list):
skip(word_list, 'stop')
start = peek(word_list)
if start == 'noun':
subj = match(word_list, 'noun')
return parse_subject(word_list, subj)
elif start == 'verb': # assume the subject is the player then
return parse_subject(word_list, ('noun', 'player'))
else:
raise ParserError("Must start with subject, object, or verb not: %s" % start)测试代码
from nose.tools import *
from DataMining import BFF27_49
def test_peek():
words = [('noun', 'apple'), ('stop', 'the'), ('verb', 'kill')]
assert_equal(BFF27_49.peek(words), 'noun')
assert_equal(BFF27_49.peek([]), None)
def test_match():
assert_equal(BFF27_49.match([], 'noun'), None)
words = [('noun','apple'),('stop','the'), ('verb','kill')]
assert_equal(BFF27_49.match(words, 'noun'), ('noun', 'apple'))
assert_equal(BFF27_49.match(words, 'verb'), None)
# def test_skip():
def test_parse_verb():
words=[('stop', 'a'), ('stop', 'the'), ('verb', 'kill'), ('noun', 'apple')]
assert_equal(BFF27_49.parse_verb(words), ('verb', 'kill'))
words_error=[('stop', 'a'), ('stop', 'the'), ('noun', 'apple'), ('verb', 'kill')]
assert_raises(BFF27_49.ParserError, BFF27_49.parse_verb, words_error)
def test_parse_object():
words = [('noun', 'apple'), ('verb', 'kill')]
assert_equal(BFF27_49.parse_object(words), ('noun', 'apple'))
words2 = [('direction', 'east'), ('verb', 'kill')]
assert_equal(BFF27_49.parse_object(words2), ('direction', 'east'))
words_error = [('stop', 'a'), ('verb', 'run'), ('verb', 'kill')]
assert_raises(BFF27_49.ParserError, BFF27_49.parse_object, words_error)
def test_parse_sentence():
words = [('stop', 'a'), ('noun', 'apple'), ('verb', 'kill'), ('direction', 'east')]
result = BFF27_49.parse_sentence(words)
assert_equal(result.subject, 'apple')
assert_equal(result.verb, 'kill')
assert_equal(result.object, 'east')