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#!/usr/bin/env python

# -*- coding: utf-8 -*-

from runner.koan import *

class AboutClasses(Koan):

class Dog:

"Dogs need regular walkies. Never, ever let them drive."

def test_instances_of_classes_can_be_created_adding_parentheses(self):

# NOTE: The .__name__ attribute will convert the class

# into a string value.

fido = self.Dog()

self.assertEqual("Dog", fido.__class__.__name__)

def test_classes_have_docstrings(self):

self.assertRegex(self.Dog.__doc__, "Dogs need regular walkies. Never, ever let them drive.")

# ------------------------------------------------------------------

class Dog2:

def __init__(self):

self._name = 'Paul'

def set_name(self, a_name):

self._name = a_name

def test_init_method_is_the_constructor(self):

dog = self.Dog2()

self.assertEqual('Paul', dog._name)

def test_private_attributes_are_not_really_private(self):

dog = self.Dog2()

dog.set_name("Fido")

self.assertEqual('Fido', dog._name)

# The _ prefix in _name implies private ownership, but nothing is truly

# private in Python.

def test_you_can_also_access_the_value_out_using_getattr_and_dict(self):

fido = self.Dog2()

fido.set_name("Fido")

self.assertEqual('Fido', getattr(fido, "_name"))

# getattr(), setattr() and delattr() are a way of accessing attributes

# by method rather than through assignment operators

self.assertEqual('Fido', fido.__dict__["_name"])

# Yes, this works here, but don't rely on the __dict__ object! Some

# class implementations use optimization which result in __dict__ not

# showing everything.

# ------------------------------------------------------------------

class Dog3:

def __init__(self):

self._name = None

def set_name(self, a_name):

self._name = a_name

def get_name(self):

return self._name

name = property(get_name, set_name)

def test_that_name_can_be_read_as_a_property(self):

fido = self.Dog3()

fido.set_name("Fido")

# access as method

self.assertEqual('Fido', fido.get_name())

# access as property

self.assertEqual('Fido', fido.name)

# ------------------------------------------------------------------

class Dog4:

def __init__(self):

self._name = None

@property

def name(self):

return self._name

@name.setter

def name(self, a_name):

self._name = a_name

def test_creating_properties_with_decorators_is_slightly_easier(self):

fido = self.Dog4()

fido.name = "Fido"

self.assertEqual("Fido", fido.name)

# ------------------------------------------------------------------

class Dog5:

def __init__(self, initial_name):

self._name = initial_name

@property

def name(self):

return self._name

def test_init_provides_initial_values_for_instance_variables(self):

fido = self.Dog5("Fido")

self.assertEqual("Fido", fido.name)

def test_args_must_match_init(self):

with self.assertRaises(TypeError):

self.Dog5()

# THINK ABOUT IT:

# Why is this so?

def test_different_objects_have_different_instance_variables(self):

fido = self.Dog5("Fido")

rover = self.Dog5("Rover")

self.assertEqual(False, rover.name == fido.name)

# ------------------------------------------------------------------

class Dog6:

def __init__(self, initial_name):

self._name = initial_name

def get_self(self):

return self

def __str__(self):

return self._name

def __repr__(self):

return "<Dog named '" + self._name + "'>"

def test_inside_a_method_self_refers_to_the_containing_object(self):

fido = self.Dog6("Fido")

self.assertEqual(fido, fido.get_self()) # Not a string!

def test_str_provides_a_string_version_of_the_object(self):

fido = self.Dog6("Fido")

self.assertEqual("Fido", str(fido))

def test_str_is_used_explicitly_in_string_interpolation(self):

fido = self.Dog6("Fido")

self.assertEqual("My dog is Fido", "My dog is " + str(fido))

def test_repr_provides_a_more_complete_string_version(self):

fido = self.Dog6("Fido")

self.assertEqual("<Dog named 'Fido'>", repr(fido))

def test_all_objects_support_str_and_repr(self):

seq = [1, 2, 3]

self.assertEqual('[1, 2, 3]', str(seq))

self.assertEqual("[1, 2, 3]", repr(seq))

self.assertEqual("STRING", str("STRING"))

self.assertEqual("'STRING'", repr("STRING"))