11-1 城市和国家： 编写一个函数，它接受两个形参：一个城市名和一个国家名。这个函数返回一个格式为City, Country 的字符串，如Santiago, Chile 。将这个函数存储在一个名为city_functions.py的模块中。
创建一个名为test_cities.py的程序，对刚编写的函数进行测试（别忘了，你需要导入模块unittest 以及要测试的函数）。编写一个名为test_city_country() 的方法，核实使用类似于’santiago’ 和’chile’ 这样的值来调用前述函数时，得到的字符串是正确的。运行test_cities.py ，确认测试test_city_country() 通过了。
答案解析：
city_functions.py
"""A collection of functions for working with cities."""
def city_country(city, country):
"""Return a String like 'Santiago Chile'."""
return (city.title() + ", " + country.title())
test_cities.py
import unittest
from city_functions import city_country
class CitiesTestCase(unittest.TestCase):
"""Tests for 'city_functions.py'."""
def test_city_country(self):
"""Does a simple city and country pair work?"""
santiago_chile = city_country('santiago', 'chile')
self.assertEqual(santiago_chile, 'Santiago, Chile')
unittest.main()
Output:
.
----------------------------------------------------------------------
Ran 1 test in 0.000s
OK
11-2 人口数量： 修改前面的函数，使其包含第三个必不可少的形参population ，并返回一个格式为City, Country - population xxx 的字符串，如Santiago, Chile - population 5000000 。运行test_cities.py，确认测试test_city_country() 未通过。
修改上述函数，将形参population 设置为可选的。再次运行test_cities.py，确认测试test_city_country() 又通过了。
再编写一个名为test_city_country_population() 的测试，核实可以使用类似于’santiago’ 、‘chile’ 和’population=5000000’ 这样的值来调用这个函数。再次运行test_cities.py，确认测试test_city_country_population() 通过了。
答案解析：
Modified city_cunctions.py, with required population parameter.
city_functions.py
"""A collection of functions for working with cities."""
def city_country(city, country, population):
"""Return a String like 'Santiago, Chile - population 5000000'."""
output_string = city.title() + ", " + country.title()
output_string += " - population " + str(population)
return output_string
Output from running test_cities.py:
E
======================================================================
ERROR: test_city_country (main.CitiesTestCase)
Does a simple city and country pair work?
----------------------------------------------------------------------
Traceback (most recent call last):
File “test_cities.py”, line 10, in test_city_country
santiago_chile = city_country(‘santiago’, ‘chile’)
TypeError: city_country() missing 1 required positional argument: ‘population’
----------------------------------------------------------------------
Ran 1 test in 0.000s
FAILED (errors=1)
Modified city_functions.py, with optional population parameter.
"""A collection of functions for working with cities."""
def city_country(city, country, population=0):
"""Return a String like 'Santiago, Chile - population 5000000'."""
output_string = city.title() + ", " + country.title()
if (population):
output_string += " - population " + str(population)
return output_string
Output of running test_cities.py
.
----------------------------------------------------------------------
Ran 1 test in 0.000s
OK
Modified test_cities.py
import unittest
from city_functions import city_country
class CitiesTestCase(unittest.TestCase):
"""Tests for 'city_functions.py'."""
def test_city_country(self):
"""Does a simple city and country pair work?"""
santiago_chile = city_country('santiago', 'chile')
self.assertEqual(santiago_chile, 'Santiago, Chile')
def test_city_country_population(self):
"""Can i include a population argument?"""
santiago_chile = city_country('santiago', 'chile', population=5000000)
self.assertEqual(santiago_chile, 'Santiago, Chile - population 5000000')
unittest.main()
Output:
. .
----------------------------------------------------------------------
Ran 2 tests in 0.000s
OK
11-3 雇员： 编写一个名为Employee的类，其方法__init__()接受名、姓和年薪，并将它们都存储在属性中。编写一个名为give_raise()的方法，它默认将年薪增加5000美元，但也能够接受其他的年薪增加量。
为Employee编写一个测试用例，其中包含两个测试方法：test_give_default_raise()和test_give_custom_taise()。使用方法setUp()，以免在每个测试方法中都创建新的雇员实例。运行这个测试用例，确认两个测试都通过了。
答案解析：
employee.py
class Employee():
"""A class to represent an employee."""
def __init__(self, f_name, l_name, salary):
self.f_name = f_name.title()
self.l_name = l_name.title()
self.salary = salary
def give_raise(self, amount=5000):
"""Give the employee a raise."""
self.salary += amount
test_employee.py
import unittest
from employee import Employee
class TestEmployee(unittest.TestCase):
"""Tests for thr module employee."""
def setUp(self):
"""Make an employee to use in tests."""
self.eric = Employee('eric', 'matthes', 65000)
def test_give_default_raise(self):
"""Test that a default raise works correctly."""
self.eric.give_raise()
self.assertEqual(self.eric.salary, 70000)
def test_give_custom_raise(self):
"""Test that a custom raise works correctly."""
self.eric.give_raise(10000)
self.assertEqual(self.eric.salary, 75000)
Output:
. .
----------------------------------------------------------------------
Ran 2 tests in 0.000s
OK
以上示例代码，可通过git用以下方式进行下载：
git clone -b python_crash_course https://gitee.com/dmpeng/python.git
代码仓库地址：
https://gitee.com/dmpeng/python/tree/python_crash_course/chapter11