11.2.2.一个要测试的类
类的测试与函数的测试相似 —— 你所做的大部分工作都是测试类中方法的行为
=======================================================
class AnonymousSurvey():
""" 收集匿名调查问卷的答案 """
def __init__(self, question):
""" 存储一个问题，并为存储答案做准备 """
self.question = question
self.responses = []
def show_question(self):
""" 显示调查问卷 """
print(self.question)
def store_response(self, new_response):
""" 存储单份调查答卷 """
self.responses.append(new_response)
def show_results(self):
""" 显示收集到的所有答卷 """
print('Survey results:')
for response in self.responses:
print('- ' + response)
=======================================================
from survey import AnonymousSurvey
# 定义一个问题，并创建一个表示调查的 AnonymousSurvey 对象
question = "What language did you first learn to speak?"
my_survey = AnonymousSurvey(question)
# 显示问题并存储答案
my_survey.show_question()
print("Enter 'q' at any time to quit.\n")
while True:
response = input("Language: ")
if response == 'q':
break
my_survey.store_response(response)
# 显示调查结果
print("\nThank you to everyone who participated in the survey!")
my_survey.show_results()
=======================================================
What language did you first learn to speak?
Enter 'q' at any time to quit.
Language: English
Language: Spanish
Language: English
Language: Mandarin
Language: q
Thank you to everyone who participated in the survey!
Survey results:
- English
- Spanish
- English
- Mandarin
11.2.3.测试 AnonymousSurvey 类
下面来编写一个测试，对 AnonymousSurvey 类的行为的一个方面进行验证：如果用户面对调查问题时只提供了一个答案，这个答案也能被妥善地存储。
=======================================================
import unittest
from survey import AnonymousSurvey
class TestAnonymousSurvey(unittest.TestCase):
"""针对AnonymousSurvey类的测试"""
def test_store_single_response(self):
"""测试单个答案会被妥善地存储"""
question = 'What language did you first learn to speak?'
my_survey = AnonymousSurvey(question)
my_survey.store_response('English')
self.assertIn('English', my_survey.responses)
unittest.main()
=======================================================
.
----------------------------------------------------------------------
Ran 1 test in 0.026s
OK
下面来核实用户提供三个答案时，它们也将被妥善地存储。为此，我们在 TestAnonymousSurvey 中再添加一个方法：
=======================================================
import unittest
from survey import AnonymousSurvey
class TestAnonymousSurvey(unittest.TestCase):
"""针对AnonymousSurvey类的测试"""
def test_store_single_response(self):
"""测试单个答案会被妥善地存储"""
question = 'What language did you first learn to speak?'
my_survey = AnonymousSurvey(question)
my_survey.store_response('English')
self.assertIn('English', my_survey.responses)
def test_store_three_responses(self):
"""测试三个答案会被妥善地存储"""
question = 'What language did you first learn to speak?'
my_survey = AnonymousSurvey(question)
responses = ['English', 'Spanish', 'Mandrin']
for response in responses:
my_survey.store_response(response)
for response in responses:
self.assertIn(response, my_survey.responses)
unittest.main()
=======================================================
..
----------------------------------------------------------------------
Ran 2 tests in 0.005s
OK
11.2.4.方法 setUp()
在前面的 test_survey.py 中，我们在每个测试方法中都创建了一个 AnonymousSurvey 实例，并在每个方法中都创建了答案。 unittest.TestCase 类包含方法 setUp() ，让我
们只需创建这些对象一次，并在每个测试方法中使用它们。如果你在 TestCase 类中包含了方法 setUp() ， Python 将先运行它，再运行各个以 test_ 打头的方法。这样，在你编写
的每个测试方法中都可使用在方法 setUp() 中创建的对象了。
=======================================================
import unittest
from survey import AnonymousSurvey
class TestAnonymousSurvey(unittest.TestCase):
"""针对AnonymousSurvey类的测试"""
def setUp(self):
"""创建一个调查对象和一组答案，供使用的测试方法使用"""
question = 'What language did you first learn to speak?'
self.my_survey = AnonymousSurvey(question)
self.responses = ['English', 'Spanish', 'Mandrin']
def test_store_single_response(self):
"""测试单个答案会被妥善地存储"""
self.my_survey.store_response(self.responses[0])
self.assertIn(self.responses[0], self.my_survey.responses)
def test_store_three_responses(self):
"""测试三个答案会被妥善地存储"""
for response in self.responses:
self.my_survey.store_response(response)
for response in self.responses:
self.assertIn(response, self.my_survey.responses)
unittest.main()
=======================================================
..
----------------------------------------------------------------------
Ran 2 tests in 0.010s
OK
11.3.小结
在本章中，你学习了：如何使用模块 unittest 中的工具来为函数和类编写测试；如何编写继承 unittest.TestCase 的类，以及如何编写测试方法，以核实函数和类的行为
符合预期；如何使用方法 setUp() 来根据类高效地创建实例并设置其属性，以便在类的所有测试方法中都可使用它们。