When it comes to tests, doctest is a great simple module to write tests for your application. However it is pretty basic and does not have any extended features like, for example, centralized unit tests. If you have multiple modules with doctests (and you probably do) you most likely want to be able to run all doctests recursively from one place. That’s where unittest comes in.

Let’s assume we store modules in the lib/ directory:

$ ls lib/
__init__.py bar.py foo.py

Here are the contents of foo.py and bar.py respectfully:

def foo():
    """
    >>> foo()
    False
    """
    return False

def bar():
    """
    >>> bar()
    True
    """
    return True

def baz():
    """
    >>> baz()
    False
    """
    return False

Now, to run all tests we need a wrapper script. Let’s call it: runtests.py:

#!/usr/bin/env python

import unittest
import doctest
import os

files = []
root_dir = 'lib/'

for root, _, filenames in os.walk(root_dir):
    for filename in filenames:
        if filename == '__init__.py' or filename[-3:] != '.py':
            continue
        f = os.path.join(root, filename)
        f = f.replace('/', '.')
        f = f[:-3]
        files.append(f)

suite = unittest.TestSuite()
for module in files:
    suite.addTest(doctest.DocTestSuite(module))
unittest.TextTestRunner(verbosity=1).run(suite)

This approach invokes the doctest.DocTestSuite method, which converts doctests strings into unittest suites. Time to run our tests:

$ chmod +x runtests.py
$ ./runtests.py
...
----------------------------------------------------------------------
Ran 3 tests in 0.008s

OK

And just to be sure that approach actually works, let’s make one of the tests fail:

$ ./runtests.py
.F.
======================================================================
FAIL: baz (lib.bar)
Doctest: lib.bar.baz
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/usr/lib/python2.7/doctest.py", line 2201, in runTest
    raise self.failureException(self.format_failure(new.getvalue()))
AssertionError: Failed doctest test for lib.bar.baz
  File "/home/rosipov/unitdoc/lib/bar.py", line 8, in baz

----------------------------------------------------------------------
File "/home/rosipov/unitdoc/lib/bar.py", line 10, in lib.bar.baz
Failed example:
    baz()
Expected:
    True
Got:
    False

----------------------------------------------------------------------
Ran 3 tests in 0.009s

FAILED (failures=1)

I had an issue with pygame not being able to find a dependency for the font module. After quite a time-consuming search the missing package name was libsdl-ttf2.0-dev.

Hope this helps someone.

Using vimdiff as a git mergetool can be pretty confusing - multiple windows and little explanation. This is a short tutorial which explains basic usage, and what the LOCAL, BASE, and REMOTE keywords mean. This implies that you have at least a little bit of basic vim knowledge (how to move, save, and switch between split windows). If you don’t, there’s a short article for you: Using vim for writing code. Some basic understanding of git and branching is required as well, obviously.

Git config

Prior to doing anything, you need to know how to set vimdiff as a git mergetool. That being said:

git config merge.tool vimdiff
git config merge.conflictstyle diff3
git config mergetool.prompt false

This will set git as the default merge tool, will display a common ancestor while merging, and will disable the prompt to open the vimdiff.

Creating merge conflict

Let’s create a test situation. You are free to skip this part or you can work along with the tutorial.

mkdir zoo
cd zoo
git init
vi animals.txt

Let’s add some animals:

cat
dog
octopus
octocat

Save the file.

git add animals.txt
git commit -m "Initial commit"
git branch octodog
git checkout octodog
vi animals.txt  # let's change octopus to octodog
git add animals.txt
git commit -m "Replace octopus with an octodog"
git checkout master
vi animals.txt  # let's change octopus to octoman
git add animals.txt
git commit -m "Replace octopus with an octoman"
git merge octodog  # merge octodog into master

That’s where we get a merge error:

Auto-merging animals.txt
CONFLICT (content): Merge conflict in animals.txt
Automatic merge failed; fix conflicts and then commit the result.

Resolving merge conflict with vimdiff

Let’s resolve the conflict:

git mergetool

This looks terrifying at first, but let me explain what is going on.

From left to right, top to the bottom:

LOCAL – this is file from the current branch BASE – common ancestor, how file looked before both changes REMOTE – file you are merging into your branch MERGED – merge result, this is what gets saved in the repo

Let’s assume that we want to keep the “octodog” change (from REMOTE). For that, move to the MERGED file (Ctrl + w, j), move your cursor to a merge conflict area and then:

:diffget RE

This gets the corresponding change from REMOTE and puts it in MERGED file. You can also:

:diffg RE  " get from REMOTE
:diffg BA  " get from BASE
:diffg LO  " get from LOCAL

Save the file and quit (a fast way to write and quit multiple files is :wqa).

Run git commit and you are all set!

This alias has been around the web for quite some time, but it does look fantastic indeed.

To add the alias git pretty-log, execute the following command (join string prior to executing):

git config alias.pretty-log 'log --graph --pretty=format:"%Cred%h%Creset
-%C(yellow)%d%Creset %s %Cgreen(%cr) %C(bold blue)<%an>%Creset"'

I wrote a little script to download gists from the command prompt.

Generate your Github API Token under Settings -> Applications, change it within a script, and then:

chmod +x shgist.py
mv shgist.py ~/bin/shgist

Where ~/bin is a directory in your path. Now you can use it as shgist file to quickly download your gists (Gist on Github).

#!/usr/bin/env python

# Ruslan Osipov <ruslan@rosipov.com>
# Usage: shgist keywords
# Description: Gists downloader

import urllib
import urllib2
import sys
import json

token = 'Personal API Access Token'  # Github Settings -> Applications

class Gist:
    def __init__(self, token):
        """
        token -- str, github token
        """
        self.token = token
        self.url = 'https://api.github.com'

    def find_by_name(self, keywords):
        """
        keywords -- list of strings
        """
        gists, urls = self._get_gists()
        for i, gist in enumerate(gists):
            for keyword in keywords:
                if keyword not in gist:
                    del gists[i]
                    del urls[i]
                    break
        if len(gists) == 0:
            print "Sorry, no gists matching your description"
            return
        if len(gists) == 1:
            self._download_gist(gists[0], urls[0])
            return
        for i, gist in enumerate(gists):
            print i, gist
        while True:
            num = raw_input("Gist number, 'q' to quit: ")
            if num == 'q':
                print "Quiting..."
                return
            try:
                num = int(num)
                if 0 <= num < len(gists):
                    break
                print "Number should be within specified range"
            except:
                print "Only integers or 'q' are allowed"
        self._download_gist(gists[num], urls[num])

    def _download_gist(self, name, url):
        """
        name -- str, filename
        url -- str, raw gist url
        """
        print "Downloading %s..." % name
        gist = self._send_get_request(url)
        open(name, 'wb').write(gist)

    def _get_gists(self):
        """
        Returns 2 lists which should be treated as ordered dict
        """
        url = '/gists'
        response = self._send_get_request(self.url + url)
        response = json.loads(response)
        gists, urls = [], []
        for gist in response:
            for name, meta in gist['files'].items():
                gists.append(name)
                urls.append(meta['raw_url'])
        return gists, urls

    def _send_get_request(self, url):
        """
        url -- str
        """
        headers = {
                'Authorization': 'token ' + self.token
                }
        request = urllib2.Request(url, headers=headers)
        response = urllib2.urlopen(request)
        return response.read()

argv = sys.argv[1:]
if not len(argv):
    print "Usage: shgist keywords"
    sys.exit(0)

gist = Gist(token)
gist.find_by_name(argv)