Unit testing with PyUnit

For much greater detail, check out the Python UnitTest Documentation

Python's unittest module provides a framework for automated unit testing (based on the Java unit test framework).

In essence, you create a class for each of a collection of test sets, following the naming and inheritance conventions described in the code example below, and you can then automatically run all test cases from each of the test sets.

Here is a simple example: 

#! /usr/bin/env python

# ==========================================================
#    Set up paths and import all necessary components
#

# import the system module and python's unit testing module
import sys, unittest

# import the module to be tested
from MyPythonDotpyFileToBeTested import *

# set up a simple test class
class TestSetOne(unittest.TestCase):

    def setUp(self):
        """Automatically called to set up each test case below"""
        # do whatever you want to set things up before these test cases
        print "setting up a test from set one"

    def tearDown(self):
        """Automatically called to clean up after each test case below"""
        # do whatever you want to clean things up
        print "cleaning up a test from set one"

    def testA(self):
        """Test case names MUST begin with the word test"""
        print "test A"

    def testB(self):
        """Test case ordering is alphabetic by method name"""
        print "test B"

class TestSetTwo(unittest.TestCase):
    
    def setUp(self):
        """Automatically called to set up each test case below"""
        # do whatever you want to set things up before these test cases
        print "setting up a test from set two"

    def tearDown(self):
        """Automatically called to clean up after each test case below"""
        # do whatever you want to clean things up
        print "cleaning up a test from set two"

    def test2(self):
        """Test case names MUST begin with the word test"""
        print "test2"

    def test1(self):
        """Test case ordering is alphabetic by method name"""
        print "test1"

        
# run all tests from all sets
if __name__ == "__main__":
    unittest.main()

Python and MySQL

Method 1 (Hack)

If one doesn't have access to a Python interface for the database you want to use, you can use python's getoutput command to run a Unix/Linux command and capture the resulting output as a string.

For instance, we can use the popen command in the os module to run a linux/unix command, and store the results in a variable. We can then use the readline() command to step through these stored results one line of output at a time, e.g.: 
import os
results = os.popen("some command", "r", 100)
nextline = results.readline()
print nextline
The parameters to popen are the command to be run, the mode (read or write), and the maximum buffer size to use to store the results.

If we are interested in running a MySQL query, then our command might be built and executed something like 
#! /usr/bin/env python

import os

executable = "/usr/local/mysql/bin/mysql"
user = "wesselsd"
password = "something clever"
hostname = "localhost"
sqlcommand = "\"show databases;\""
cmd = executable + " -u" + user + " -p" + password +  " -e" + sqlcommand;
result = os.popen(cmd, "r")
for nextline in result.readlines():
	print nextline

Method 2 (Cleaner)

The standard method to access a MySQL database in a python script uses the MySQLdb module to establish a connection to the database, and then creates a cursor through which to access the database.

With that set up (see the example below) one can runn selects, inserts, etc using the cursor execute method.

When doing selects, we usually retrieve multiple rows, each with multiple columns of data. The collection of rows can be retrieved using the fetchall() method, and then accessed one at a time using a for-in loop, as illustrated below. Note that each row will be an array of multiple strings (one per column).

When doing inserts, it is probably easiest to use the triple-double quoted strings approach to prevent our insertion string from being parsed by Python before it gets to the database. Again, see the example below. 
import MySQLdb

# connect to the db and obtain a cursor
db = MySQLdb.connect(host="localhost", user="joe", passwd="secret", db="databasename")
cursor = db.cursor()

# example of running a select statement and parsing the results
cursor.execute("SELECT * FROM *")
result = cursor.fetchall()
for record in result:
	# print the fields of the record
	print record[0],record[1], etc

# example of running an insert statement
cursor.execute("""INSERT INTO tablename (colname, colname) VALUES ("BLAH", "BLAH")""")

Python and Tkinter

Tkinter is a Python interface to the Tk GUI toolkit, and is a quick and effective way to put together user interfaces. Unfortunately, the current Python configurations on csciun1 don't support it, but if you want to experiment with it in the windows labs or at home then the following are good introductory tutorials:

For now simply import the whole thing, e.g.
from Tkinter import *

The basic process in creating GUI elements with this module is

A simple example is shown first:

GUI classes