单元测试

import unittest
 
def add(a, b):
    return a + b
 
def divide(a, b):
    if b == 0:
        raise ValueError("除数不能为 0")
    return a / b
 
class TestMath(unittest.TestCase):
    def test_add(self):
        self.assertEqual(add(3, 4), 7)
        self.assertEqual(add(-1, 1), 0)
 
    def test_divide_ok(self):
        self.assertEqual(divide(10, 2), 5)
 
    def test_divide_by_zero(self):
        with self.assertRaises(ValueError):
            divide(1, 0)
 
# 把 unittest 当主程序跑
unittest.main(argv=[''], exit=False, verbosity=2)

import unittest
import tempfile, os
 
class FileTest(unittest.TestCase):
    def setUp(self):
        # 每个测试前建一个临时文件
        self.path = tempfile.mktemp(suffix=".txt")
        with open(self.path, "w") as f:
            f.write("hello\nworld\n")
 
    def tearDown(self):
        # 每个测试后清理
        if os.path.exists(self.path):
            os.remove(self.path)
 
    def test_read_line_count(self):
        with open(self.path) as f:
            lines = f.readlines()
        self.assertEqual(len(lines), 2)
 
    def test_contains_hello(self):
        with open(self.path) as f:
            content = f.read()
        self.assertIn("hello", content)
 
unittest.main(argv=[''], exit=False, verbosity=2)

# 保存为 test_sample.py，然后用 pytest 运行
def add(a, b):
    return a + b
 
def test_add_positive():
    assert add(3, 4) == 7
 
def test_add_negative():
    assert add(-1, 1) == 0
 
def test_add_strings():
    # pytest 会显示 "hi" + "" != "hi!"
    assert add("hi", "") == "hi!"

import unittest
 
def slugify(s):
    return s.lower().strip().replace(" ", "-")
 
class TestSlugify(unittest.TestCase):
    def test_cases(self):
        cases = [
            ("Hello World", "hello-world"),
            ("  Python  ",  "python"),
            ("ALREADY-low", "already-low"),
            ("a b c d",      "a-b-c-d"),
        ]
        for input_, expected in cases:
            with self.subTest(input=input_):
                self.assertEqual(slugify(input_), expected)
 
unittest.main(argv=[''], exit=False, verbosity=2)

import unittest
from unittest.mock import patch, MagicMock
 
# 被测代码：从一个 dict 拿用户
def get_user_email(uid, db):
    user = db.fetch_user(uid)
    if not user:
        return None
    return user["email"]
 
class TestGetUserEmail(unittest.TestCase):
    @patch("__main__.db")
    def test_existing_user(self, mock_db):
        # 让 db.fetch_user 返回我们假装的数据
        mock_db.fetch_user.return_value = {"name": "Alice", "email": "a@x.com"}
        self.assertEqual(get_user_email(1, mock_db), "a@x.com")
        mock_db.fetch_user.assert_called_once_with(1)
 
    @patch("__main__.db")
    def test_missing_user(self, mock_db):
        mock_db.fetch_user.return_value = None
        self.assertIsNone(get_user_email(999, mock_db))
 
# 假装有个 db 对象
class FakeDB: pass
db = FakeDB()
 
unittest.main(argv=[''], exit=False, verbosity=2)

import unittest
from unittest.mock import patch
import time
 
# 被测代码
def wait_then_print():
    time.sleep(10)        # 真跑要 10 秒
    print("done!")
 
class TestWait(unittest.TestCase):
    @patch("time.sleep")
    def test_does_not_sleep(self, mock_sleep):
        wait_then_print()
        mock_sleep.assert_called_once_with(10)
 
unittest.main(argv=[''], exit=False, verbosity=2)

import unittest
 
def clamp(x, lo, hi):
    if x < lo: return lo
    if x > hi: return hi
    return x
 
class TestClamp(unittest.TestCase):
    def test_inside(self):
        pass
    def test_below(self):
        pass
    def test_above(self):
        pass
    def test_equal(self):
        pass
 
unittest.main(argv=[''], exit=False, verbosity=2)