forked from bslatkin/effectivepython
-
Notifications
You must be signed in to change notification settings - Fork 0
Expand file tree
/
Copy pathitem_79.py
More file actions
executable file
·166 lines (125 loc) · 3.83 KB
/
item_79.py
File metadata and controls
executable file
·166 lines (125 loc) · 3.83 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
#!/usr/bin/env PYTHONHASHSEED=1234 python3
# Copyright 2014-2019 Brett Slatkin, Pearson Education Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# Reproduce book environment
import random
random.seed(1234)
import logging
from pprint import pprint
from sys import stdout as STDOUT
# Write all output to a temporary directory
import atexit
import gc
import io
import os
import tempfile
TEST_DIR = tempfile.TemporaryDirectory()
atexit.register(TEST_DIR.cleanup)
# Make sure Windows processes exit cleanly
OLD_CWD = os.getcwd()
atexit.register(lambda: os.chdir(OLD_CWD))
os.chdir(TEST_DIR.name)
def close_open_files():
everything = gc.get_objects()
for obj in everything:
if isinstance(obj, io.IOBase):
obj.close()
atexit.register(close_open_files)
# Example 1
class ZooDatabase:
def get_animals(self, species):
pass
def get_food_period(self, species):
pass
def feed_animal(self, name, when):
pass
# Example 2
from datetime import datetime
def do_rounds(database, species, *, utcnow=datetime.utcnow):
now = utcnow()
feeding_timedelta = database.get_food_period(species)
animals = database.get_animals(species)
fed = 0
for name, last_mealtime in animals:
if (now - last_mealtime) >= feeding_timedelta:
database.feed_animal(name, now)
fed += 1
return fed
# Example 3
from unittest.mock import Mock
database = Mock(spec=ZooDatabase)
print(database.feed_animal)
database.feed_animal()
database.feed_animal.assert_any_call()
# Example 4
from datetime import timedelta
from unittest.mock import call
now_func = Mock(spec=datetime.utcnow)
now_func.return_value = datetime(2019, 6, 5, 15, 45)
database = Mock(spec=ZooDatabase)
database.get_food_period.return_value = timedelta(hours=3)
database.get_animals.return_value = [
('Spot', datetime(2019, 6, 5, 11, 15)),
('Fluffy', datetime(2019, 6, 5, 12, 30)),
('Jojo', datetime(2019, 6, 5, 12, 55))
]
# Example 5
result = do_rounds(database, 'Meerkat', utcnow=now_func)
assert result == 2
database.get_food_period.assert_called_once_with('Meerkat')
database.get_animals.assert_called_once_with('Meerkat')
database.feed_animal.assert_has_calls(
[
call('Spot', now_func.return_value),
call('Fluffy', now_func.return_value),
],
any_order=True)
# Example 6
try:
database.bad_method_name()
except:
logging.exception('Expected')
else:
assert False
# Example 7
DATABASE = None
def get_database():
global DATABASE
if DATABASE is None:
DATABASE = ZooDatabase()
return DATABASE
def main(argv):
database = get_database()
species = argv[1]
count = do_rounds(database, species)
print(f'Fed {count} {species}(s)')
return 0
# Example 8
import contextlib
import io
from unittest.mock import patch
with patch('__main__.DATABASE', spec=ZooDatabase):
now = datetime.utcnow()
DATABASE.get_food_period.return_value = timedelta(hours=3)
DATABASE.get_animals.return_value = [
('Spot', now - timedelta(minutes=4.5)),
('Fluffy', now - timedelta(hours=3.25)),
('Jojo', now - timedelta(hours=3)),
]
fake_stdout = io.StringIO()
with contextlib.redirect_stdout(fake_stdout):
main(['program name', 'Meerkat'])
found = fake_stdout.getvalue()
expected = 'Fed 2 Meerkat(s)\n'
assert found == expected