Unit testing for two difference implementations

[python101]

[code=python]
class Calculation:
def __init__(self, A=0, B=1):
factor = gcd( abs(A), abs(B) )
if B < 0:
factor = -factor
self._numA = A // factor
self._denoB = B // factor


def __str__(self):
return str(self._numA) + '/' + str(self._denoB )

# now I have 2 different implementations for __int__"
#either 1:
def __int__(self):
return int(float(self) )

# or 2 is used:
def __int__(self):
return self._numA/self._denoB

[/code]

My question is how can I a write a unit test (__name__='__ma in__') to test for which these two implementations produce different result?

[bartonc]

How about commenting out first one, then the other, since you will only have one (the second one defined), anyway.

[python101]

I tried to test individual implementation but both gave the same result. Can anyone give a case that two implementations will have two different results?

[bvdet]

[code=python]
class Calculation:
def __init__(self, A=0, B=1):
factor = gcd( abs(A), abs(B) )
if B < 0:
factor = -factor
self._numA = A // factor
self._denoB = B // factor


def __str__(self):
return str(self._numA) + '/' + str(self._denoB )

# now I have 2 different implementations for __int__"
#either 1:
def __int__(self):
return int(float(self) )

# or 2 is used:
def __int__(self):
return self._numA/self._denoB

[/code]

My question is how can I a write a unit test (__name__='__ma in__') to test for which these two implementations produce different result?

It looks like they return the same thing.[code=Python]
def gcd(m,n):
if n == 0: return m
return gcd(n,m%n)

class Calculation:
def __init__(self, A=0, B=1):
factor = gcd( abs(A), abs(B) )
if B < 0:
factor = -factor
self._numA = A // factor
self._denoB = B // factor

def __str__(self):
return str(self._numA) + '/' + str(self._denoB )

def __float__(self) :
return float(self._num A)/self._denoB

def __int__(self):
return self._numA/self._denoB


class Calc(Calculatio n):
def __init__(self, A=0, B=1):
Calculation.__i nit__(self, A, B)

def __int__(self):
return int(float(self) )

if __name__ == '__main__':
test = (302, 22)

a = Calculation(*te st)
print int(a)

b = Calc(*test)
print int(b)

print float(a) [/code]>>> 13
13
13.7272727273
>>>

[bvdet]

Here is a test for a range of numbers:[code=Python]if __name__ == '__main__':

testList = [(i,j) for i in xrange(9,109) for j in xrange(6,80)]
strList = []
for test in testList:
a = Calculation(*te st)
b = Calc(*test)
strList.append( (int(a), int(b), float(a)))
print '\n'.join(['%d %d %0.6f' % item for item in strList])[/code]This test does not print anything if results are the same:[code=Python]if __name__ == '__main__':
testList = [(i,j) for i in xrange(9,2000) for j in xrange(6,80)]
for test in testList:
a = Calculation(*te st)
b = Calc(*test)
if int(a) != int(b):
print int(a), int(b)[/code]

[bvdet]

There is a difference when one of the numbers is negative:[code=Python]if __name__ == '__main__':
testList = [(i,j) for i in xrange(-9,500,2) for j in xrange(-7,80,2)]
for test in testList:
a = Calculation(*te st)
b = Calc(*test)
if int(a) != int(b):
print test[0], test[1], int(a), int(b), str(a), str(b)[/code][code=Python]
............
-1 63 -1 0 -1/63 -1/63
-1 65 -1 0 -1/65 -1/65
-1 67 -1 0 -1/67 -1/67
-1 69 -1 0 -1/69 -1/69
-1 71 -1 0 -1/71 -1/71
-1 73 -1 0 -1/73 -1/73
-1 75 -1 0 -1/75 -1/75
-1 77 -1 0 -1/77 -1/77
-1 79 -1 0 -1/79 -1/79
1 -7 -1 0 -1/7 -1/7
1 -5 -1 0 -1/5 -1/5
1 -3 -1 0 -1/3 -1/3
3 -7 -1 0 -3/7 -3/7
3 -5 -1 0 -3/5 -3/5
5 -7 -1 0 -5/7 -5/7
5 -3 -2 -1 -5/3 -5/3
7 -5 -2 -1 -7/5 -7/5
7 -3 -3 -2 -7/3 -7/3
............... ..........[/code]

[python101]

thank you very much.