Chapter 0

import types
import unittest

class TestAccess( unittest.TestCase ):
    def test_should_add_and_get_attribute( self ):
        self.object.new_attribute= True
        self.assertTrue( self.object.new_attribute )
    def test_should_fail_on_missing( self ):
        self.assertRaises( AttributeError, lambda: self.object.undefined )

class SomeClass:
    pass

class Test_EmptyClass( TestAccess ):
    def setUp( self ):
       self.object= SomeClass()

class Test_Namespace( TestAccess ):
    def setUp( self ):
       self.object= types.SimpleNamespace()

class Test_Object( TestAccess ):
    def setUp( self ):
       self.object= object()

def suite():
    s= unittest.TestSuite()
    s.addTests( unittest.defaultTestLoader.loadTestsFromTestCase(Test_EmptyClass) )
    s.addTests( unittest.defaultTestLoader.loadTestsFromTestCase(Test_Namespace) )
    s.addTests( unittest.defaultTestLoader.loadTestsFromTestCase(Test_Object) )
    return s

if __name__ == "__main__":
    t= unittest.TextTestRunner()
    t.run( suite() )

def factorial( n ):
    """Compute n! recursively.

    :param n: an integer >= 0
    :returns: n!

    Because of Python's stack limitation, this won't
    compute a value larger than about 1000!.
    """
    if n == 0: return 1
    return n*factorial(n-1)

print( "5!=", factorial(5) )