Cal helper files

example_cal.py

print("""   September 2017
Su Mo Tu We Th Fr Sa
                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
""")

sysargv_example.py

import sys

command_line_args = sys.argv[1:] # all but the first one

for arg in command_line_args:
    print(arg)
    

test_cal.py

import pytest  # 'pip install pytest'  in your virtual env

import subprocess  # what we use to call the python file and the 'cal' command to get their output

MY_FILE = 'example_cal.py'  # change to whatever yours is


def create_command(command, *args): # helper function
    """
    Returns either
    'python cal.py arg1 arg2'
    or
    'cal arg1 arg2'

    to pass to the subprocess.getoutput function
    Takes any number of args

    i.e

    >>> create_command('some_python_file.py' 8, 2017)
    'python some_python_file 8 2017'
    >>> create_command('cal', 2012)
    'cal 2012'
    """
    if command.endswith('py'):
        command = 'python ' + command
    args = [str(arg) for arg in args]
    return ' '.join([command] + args)


def test_september_this_year():
    mine = create_command(MY_FILE, 9, 2017)
    cals = create_command('cal', 9, 2017)

    mine_output = subprocess.getoutput(mine)
    cals_output = subprocess.getoutput(cals)

    assert mine_output == cals_output


def test_feb_leap_year():
    mine = create_command(MY_FILE, 2, 2008)
    cals = create_command('cal', 2, 2008)

    mine_output = subprocess.getoutput(mine)
    cals_output = subprocess.getoutput(cals)

    assert mine_output == cals_output


def test_whole_year():
    mine = create_command(MY_FILE, 2001)
    cals = create_command('cal', 2001)


    mine_output = subprocess.getoutput(mine)
    cals_output = subprocess.getoutput(cals)

    assert mine_output == cals_output

Getting command line arguments:

You can get the command line arguments passed into your python file
i.e.
python my_calendar 8 2011 will have the arguments '8' and '2011'

These can be accessed via sys.argv. I've attached an example file that simply loops over any arguments passed in and prints them. Just copy the code up to command_line_args = ... and you can use that if you wish.

see: http://www.pythonforbeginners.com/system/python-sys-argv

Some example tests that compare the output of your code to the native 'cal' command.

Note: it's going to be finicky when it comes to spaces.

Testing

install pytest with:

source env/bin/activate to activate your virtual env
pip install pytest

Download the test_cal.py file and put it in the same folder as your cal.py (or whatever you called it). Edit MY_FILE to be the name of your calendar python file. In the above, i am pointing it to example-cal.py

Run the tests with:

pytest -xvv test_cal.py
the -x means stop after first failing test
the vv means very verbose, show me the full difference.

RED is a faling test
GREEN is a test that passed.
should look something like