unittest使用signal信号量

unittest 3.2版中更新了signal信号量的功能，用于在遇到Ctrl+C键盘中断时优雅的结束。
当用户按下Ctrl+C时，会立即或等当前用例执行完后再停止运行，并输出结果，如果用户再次按下Ctrl+C，则会立即抛出KeyboardInterrupt异常并停止。

启用singal功能的方法有以下3种：
示例用例test_demo.py内容如下：

import unittest

class TestDemo(unittest.TestCase):
    def test_a(self):
        pass

    def test_b(self):
        time.sleep(10)

    def test_c(self):
        time.sleep(10)
        pass

命令行运行时加上-c或--catch参数

python -m unittest -vvv -c test_demo

此时按下Ctrl+C，会立即停止运行，并输出结果：

test_a (test_demo1.TestDemo) ... ok
test_b (test_demo1.TestDemo) ... ^Cok

----------------------------------------------------------------------
Ran 2 tests in 1.106s

OK

在unittest.main()中使用参数catchbreak=True

在脚本test_demo.py中添加：

if __name__ == '__main__':
    unittest.main(verbosity=2, catchbreak=True)

命令行中使用python命令运行该脚本：

python test_demo.py

按下Ctrl+C，此时程序不会立即停止运行，而是等该用例执行完后，再停止运行，输出结果如下：

test_a (__main__.TestDemo) ... ok
test_b (__main__.TestDemo) ... ^Cok

----------------------------------------------------------------------
Ran 2 tests in 30.005s

在suite中使用signal

新建run.py，代码如下：

import unittest
import test_demo

# 启用信号量功能
result = unittest.TestResult()
unittest.installHandler()
unittest.registerResult(result)

suite = unittest.defaultTestLoader.loadTestsFromModule(test_demo)
runner = unittest.TextTestRunner(verbosity=2)
runner.run(suite)

命令行使用python运行run.py：

python run.py

按下Ctrl+C，等待第二条用例执行完后会停止运行，结果同上一个结果。再次按下Ctrl+C则会立即停止，输出如下：

test_a (test_demo1.TestDemo) ... ok
test_b (test_demo1.TestDemo) ... ^C^CTraceback (most recent call last):
  File "run.py", line 11, in <module>
    runner.run(suite)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/unittest/runner.py", line 176, in run
    test(result)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/unittest/suite.py", line 84, in __call__
    return self.run(*args, **kwds)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/unittest/suite.py", line 122, in run
    test(result)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/unittest/suite.py", line 84, in __call__
    return self.run(*args, **kwds)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/unittest/suite.py", line 122, in run
    test(result)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/unittest/case.py", line 653, in __call__
    return self.run(*args, **kwds)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/unittest/case.py", line 605, in run
    testMethod()
  File "/Users/apple/Documents/Projects/Secoo/rpa/outputs/test_demo1.py", line 12, in test_b
    time.sleep(30)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/unittest/signals.py", line 36, in __call__
    self.default_handler(signum, frame)
KeyboardInterrupt