如何使用assert、actual变量及siminput为时间转换代码编写unittest测试用例

原代码直接耦合了输入输出逻辑，没法单独验证转换功能。先把核心转换逻辑和交互逻辑拆分，这样测试起来更方便：

def convert_hours_to_mins(hours):
    return hours * 60

def convert_mins_to_hours(mins):
    return mins / 60

def conversion():
    print('Would you like to convert hours to mins, or mins to hours?')
    choice = input().strip()

    if choice == 'hours to mins':
        hours = int(input('How many hours? '))
        mins = convert_hours_to_mins(hours)
        print(f"{mins} Minutes")
    elif choice == 'mins to hours':
        mins = int(input('How many minutes? '))
        hours = convert_mins_to_hours(mins)
        print(f"{hours} Hours")
    else:
        print('An error has occurred')

if __name__ == "__main__":
    conversion()

用unittest框架，结合unittest.mock模拟输入、捕获输出，再用assert验证结果：

import unittest
from unittest.mock import patch
# 替换成你的生产代码文件名
from your_script_name import convert_hours_to_mins, convert_mins_to_hours, conversion

class TestTimeConversion(unittest.TestCase):
    # 测试核心转换函数
    def test_hours_to_mins(self):
        actual = convert_hours_to_mins(2)
        self.assertEqual(actual, 120)
        
        actual = convert_hours_to_mins(0)
        self.assertEqual(actual, 0)
        
        actual = convert_hours_to_mins(1.5)
        self.assertEqual(actual, 90)

    def test_mins_to_hours(self):
        actual = convert_mins_to_hours(120)
        self.assertEqual(actual, 2.0)
        
        actual = convert_mins_to_hours(30)
        self.assertEqual(actual, 0.5)
        
        actual = convert_mins_to_hours(0)
        self.assertEqual(actual, 0.0)

    # 测试完整交互流程
    @patch('builtins.input')
    @patch('builtins.print')
    def test_conversion_hours_to_mins(self, mock_print, mock_input):
        # 模拟用户依次输入的内容
        mock_input.side_effect = ['hours to mins', '3']
        conversion()
        # 验证输出是否符合预期
        mock_print.assert_any_call('Would you like to convert hours to mins, or mins to hours?')
        mock_print.assert_any_call('180 Minutes')

    @patch('builtins.input')
    @patch('builtins.print')
    def test_conversion_mins_to_hours(self, mock_print, mock_input):
        mock_input.side_effect = ['mins to hours', '180']
        conversion()
        mock_print.assert_any_call('Would you like to convert hours to mins, or mins to hours?')
        mock_print.assert_any_call('3.0 Hours')

    @patch('builtins.input')
    @patch('builtins.print')
    def test_conversion_invalid_choice(self, mock_print, mock_input):
        mock_input.return_value = 'invalid option'
        conversion()
        mock_print.assert_any_call('Would you like to convert hours to mins, or mins to hours?')
        mock_print.assert_any_call('An error has occurred')

if __name__ == '__main__':
    unittest.main()

• 拆分核心逻辑：把转换计算单独抽成函数，直接用actual变量接收函数返回值，再通过self.assertEqual(actual, 预期值)验证结果。
• 模拟输入：用@patch('builtins.input')替换系统的input函数，side_effect可以按顺序提供模拟的用户输入内容。
• 捕获输出：用@patch('builtins.print')捕获print的调用，通过断言验证输出内容是否正确。

内容的提问来源于stack exchange，提问作者noisoyhermando