如何对不带参数的python函数进行单元测试？

import unittest

class TestMyFunction(unittest.TestCase):
    pass

class TestMyFunction(unittest.TestCase):
    def test_function_name(self):
        # 测试代码
        pass

class TestMyFunction(unittest.TestCase):
    def test_function_name(self):
        result = function_name()  # 调用待测试的函数
        self.assertEqual(result, expected_result)  # 使用断言判断结果是否符合预期

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

import unittest

def my_function():
    return "Hello, World!"

class TestMyFunction(unittest.TestCase):
    def test_my_function(self):
        result = my_function()
        self.assertEqual(result, "Hello, World!")

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