#
# An example that shows the use of unit
# testing
#


# The programmer initially wrote these functions,
# that correctly converts degrees celcius to fahrenheit and back.


def f_to_c(temp):
    """ Convert fahrenheit to celcius """
    return (temp - 32.0)*5.0/9.0

def c_to_f(temp):
    """ Convert celcius to fahrenheit """
    return temp*9.0/5.0 + 32.0

# Some test functions are  written in a separate file,
# say "test_temperatures.py"

# Now two years later, the programmer decides to
# clean things up a litle, and modifies the functions:

def f_to_c(temp):
    """ Convert fahrenheit to celcius """
    return (temp - 32)*5/9


def c_to_f(temp):
    """ Convert celcius to fahrenheit """
    return temp*9/5 + 32

# These functions are buggy! If temp
# is an integer, a situation that is quite realistic,
# division may give bad results ...
# Luckily the tests can capture this, if they are well written


# http://articles.latimes.com/1999/oct/01/news/mn-17288