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
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
|
FreezeGun: Let your Python tests travel through time
====================================================
.. image:: https://img.shields.io/pypi/v/freezegun.svg
:target: https://pypi.python.org/pypi/freezegun/
.. image:: https://secure.travis-ci.org/spulec/freezegun.svg?branch=master
:target: https://travis-ci.org/spulec/freezegun
.. image:: https://coveralls.io/repos/spulec/freezegun/badge.svg?branch=master
:target: https://coveralls.io/r/spulec/freezegun
FreezeGun is a library that allows your Python tests to travel through time by mocking the datetime module.
Usage
-----
Once the decorator or context manager have been invoked, all calls to datetime.datetime.now(), datetime.datetime.utcnow(), datetime.date.today(), time.time(), time.localtime(), time.gmtime(), and time.strftime() will return the time that has been frozen.
Decorator
~~~~~~~~~
.. code-block:: python
from freezegun import freeze_time
import datetime
import unittest
@freeze_time("2012-01-14")
def test():
assert datetime.datetime.now() == datetime.datetime(2012, 1, 14)
# Or a unittest TestCase - freezes for every test, from the start of setUpClass to the end of tearDownClass
@freeze_time("1955-11-12")
class MyTests(unittest.TestCase):
def test_the_class(self):
assert datetime.datetime.now() == datetime.datetime(1955, 11, 12)
# Or any other class - freezes around each callable (may not work in every case)
@freeze_time("2012-01-14")
class Tester(object):
def test_the_class(self):
assert datetime.datetime.now() == datetime.datetime(2012, 1, 14)
Context manager
~~~~~~~~~~~~~~~
.. code-block:: python
from freezegun import freeze_time
def test():
assert datetime.datetime.now() != datetime.datetime(2012, 1, 14)
with freeze_time("2012-01-14"):
assert datetime.datetime.now() == datetime.datetime(2012, 1, 14)
assert datetime.datetime.now() != datetime.datetime(2012, 1, 14)
Raw use
~~~~~~~
.. code-block:: python
from freezegun import freeze_time
freezer = freeze_time("2012-01-14 12:00:01")
freezer.start()
assert datetime.datetime.now() == datetime.datetime(2012, 1, 14, 12, 0, 1)
freezer.stop()
Timezones
~~~~~~~~~
.. code-block:: python
from freezegun import freeze_time
@freeze_time("2012-01-14 03:21:34", tz_offset=-4)
def test():
assert datetime.datetime.utcnow() == datetime.datetime(2012, 1, 14, 3, 21, 34)
assert datetime.datetime.now() == datetime.datetime(2012, 1, 13, 23, 21, 34)
# datetime.date.today() uses local time
assert datetime.date.today() == datetime.date(2012, 1, 13)
@freeze_time("2012-01-14 03:21:34", tz_offset=-datetime.timedelta(hours=3, minutes=30))
def test_timedelta_offset():
assert datetime.datetime.now() == datetime.datetime(2012, 1, 13, 23, 51, 34)
Nice inputs
~~~~~~~~~~~
FreezeGun uses dateutil behind the scenes so you can have nice-looking datetimes.
.. code-block:: python
@freeze_time("Jan 14th, 2012")
def test_nice_datetime():
assert datetime.datetime.now() == datetime.datetime(2012, 1, 14)
Function and generator objects
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
FreezeGun is able to handle function and generator objects.
.. code-block:: python
def test_lambda():
with freeze_time(lambda: datetime.datetime(2012, 1, 14)):
assert datetime.datetime.now() == datetime.datetime(2012, 1, 14)
def test_generator():
datetimes = (datetime.datetime(year, 1, 1) for year in range(2010, 2012))
with freeze_time(datetimes):
assert datetime.datetime.now() == datetime.datetime(2010, 1, 1)
with freeze_time(datetimes):
assert datetime.datetime.now() == datetime.datetime(2011, 1, 1)
# The next call to freeze_time(datetimes) would raise a StopIteration exception.
``tick`` argument
~~~~~~~~~~~~~~~~~
FreezeGun has an additional ``tick`` argument which will restart time at the given
value, but then time will keep ticking. This is alternative to the default
parameters which will keep time stopped.
.. code-block:: python
@freeze_time("Jan 14th, 2020", tick=True)
def test_nice_datetime():
assert datetime.datetime.now() > datetime.datetime(2020, 1, 14)
``auto_tick_seconds`` argument
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
FreezeGun has an additional ``auto_tick_seconds`` argument which will autoincrement the
value every time by the given amount from the start value. This is alternative to the default
parameters which will keep time stopped. Note that given ``auto_tick_seconds`` the ``tick`` parameter will be ignored.
.. code-block:: python
@freeze_time("Jan 14th, 2020", auto_tick_seconds=15)
def test_nice_datetime():
first_time = datetime.datetime.now()
auto_incremented_time = datetime.datetime.now()
assert first_time + datetime.timedelta(seconds=15) == auto_incremented_time
Manual ticks
~~~~~~~~~~~~
FreezeGun allows for the time to be manually forwarded as well.
.. code-block:: python
def test_manual_increment():
initial_datetime = datetime.datetime(year=1, month=7, day=12,
hour=15, minute=6, second=3)
with freeze_time(initial_datetime) as frozen_datetime:
assert frozen_datetime() == initial_datetime
frozen_datetime.tick()
initial_datetime += datetime.timedelta(seconds=1)
assert frozen_datetime() == initial_datetime
frozen_datetime.tick(delta=datetime.timedelta(seconds=10))
initial_datetime += datetime.timedelta(seconds=10)
assert frozen_datetime() == initial_datetime
Moving time to specify datetime
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
FreezeGun allows moving time to specific dates.
.. code-block:: python
def test_move_to():
initial_datetime = datetime.datetime(year=1, month=7, day=12,
hour=15, minute=6, second=3)
other_datetime = datetime.datetime(year=2, month=8, day=13,
hour=14, minute=5, second=0)
with freeze_time(initial_datetime) as frozen_datetime:
assert frozen_datetime() == initial_datetime
frozen_datetime.move_to(other_datetime)
assert frozen_datetime() == other_datetime
frozen_datetime.move_to(initial_datetime)
assert frozen_datetime() == initial_datetime
@freeze_time("2012-01-14", as_arg=True)
def test(frozen_time):
assert datetime.datetime.now() == datetime.datetime(2012, 1, 14)
frozen_time.move_to("2014-02-12")
assert datetime.datetime.now() == datetime.datetime(2014, 2, 12)
Parameter for ``move_to`` can be any valid ``freeze_time`` date (string, date, datetime).
Default arguments
~~~~~~~~~~~~~~~~~
Note that FreezeGun will not modify default arguments. The following code will
print the current date. See `here <http://docs.python-guide.org/en/latest/writing/gotchas/#mutable-default-arguments>`_ for why.
.. code-block:: python
from freezegun import freeze_time
import datetime as dt
def test(default=dt.date.today()):
print(default)
with freeze_time('2000-1-1'):
test()
Installation
------------
To install FreezeGun, simply:
.. code-block:: bash
$ pip install freezegun
On Debian systems:
.. code-block:: bash
$ sudo apt-get install python-freezegun
|
