https://github.com/hitchdev/faketime

Python wrapper around libfaketime.
https://github.com/hitchdev/faketime

Last synced: about 2 months ago
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Python wrapper around libfaketime.

• Host: GitHub
• URL: https://github.com/hitchdev/faketime
• Owner: hitchdev
• License: gpl-2.0
• Created: 2015-05-24T11:03:13.000Z (over 9 years ago)
• Default Branch: master
• Last Pushed: 2019-10-12T16:19:05.000Z (about 5 years ago)
• Last Synced: 2024-10-08T10:11:35.904Z (3 months ago)
• Language: C
• Size: 83 KB
• Stars: 7
• Watchers: 2
• Forks: 3
• Open Issues: 5
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# Faketime

Faketime is a thin python wrapper around the amazing C library [libfaketime](https://github.com/wolfcw/libfaketime), written

by [Wolfgang Hommel](https://github.com/wolfcw) which you can use to lie to UNIX processes about what time and date it is.

## Why does this wrapper exist?

* It provides an interface that is convenient and pythonic that you can use to lie to subprocesses run with python.

* It provides an python interface that is identical on both Mac OS X and Linux (libfaketime is used in a slightly different way on both).

* It provides a self contained library that can be installed in a virtualenv that runs consistently in any environment - installing libfaketime from package manager can instead get you older, buggy versions on different operating systems and package managers.

## Install

```

pip install faketime

```

## Using

```

>>> from commandlib import Command

>>> from faketime import Faketime

>>> from datetime import datetime

>>> faketime = Faketime("currenttime.txt")

>>> datecmd

{'LD_PRELOAD': '/full/path/to/virtualenv/site-packages/faketime/libfaketime.so.1', 'FAKETIME_TIMESTAMP_FILE': '/full/path/to/currenttime.txt'}

>>> datecmd = Command("date").with_env(**faketime.env_vars)

>>> datecmd.run()

[ should print current time ]

>>> faketime.change_time(datetime(2050, 6, 7, 10, 9, 22, 713689))

>>> datecmd.run()

Tue  7 Jun 10:09:21 BST 2050

```

This above example shows how to use faketime with [commandlib](https://hitchdev.com/commandlib/), although

the environment variables in the dict can be used with any command runner (e.g. Popen).

## What's the story behind this library?

This library can be used for a number of purposes, but I mainly built it so that I could write

tests with [hitchstory](https://hitchdev.com/hitchstory) that would lie to postgres,

django and celery simultaneously about what date and time it was.

Initially I tried using [freezegun](https://github.com/spulec/freezegun) to test the python code, but I realized that it only really

worked on one snippet of code at a time. Moreover:

* If that code executed a python process that contained other code that other code would get the *current* time, not the frozen time, breaking the test.

* It was simply incapable of faking, say, postgres's time, so if an SQL query embedded a datetime query then that would break the test.