#format python
"""Example of Recursion and PyUnit and AssertiveProgramming and FunctionalProgramming
"""

import unittest

def fact(aNum):
    assert aNum >= 1 and type(aNum) == int
    if aNum == 1:
        return 1
    else:
        return aNum * fact(aNum-1)

factFP = lambda n: n<=1 and 1 or factFP(n-1)*n

class FactorialTest(unittest.TestCase):
    def test1(self):
        self.assertEquals(1, fact(1))
    def test2(self):
        self.assertEquals(2, fact(2))
        self.assertEquals(6, fact(3))
    def testNegativeOrFloat(self):
        self.assertRaises(AssertionError, fact, -2)
        self.assertRaises(AssertionError, fact, 1.1)
    def testOtherTypes(self):
        self.assertRaises(AssertionError, fact, 'a')
        
if __name__=='__main__':
    unittest.main(argv=('','-v'))