test_sys_settrace.py 文件源码

def test_exception_arguments(self):
        def f():
            x = 0
            # this should raise an error
            x.no_such_attr
        def g(frame, event, arg):
            if (event == 'exception'):
                type, exception, trace = arg
                self.assertIsInstance(exception, Exception)
            return g

        existing = sys.gettrace()
        try:
            sys.settrace(g)
            try:
                f()
            except AttributeError:
                # this is expected
                pass
        finally:
            sys.settrace(existing)


# 'Jump' tests: assigning to frame.f_lineno within a trace function
# moves the execution position - it's how debuggers implement a Jump
# command (aka. "Set next statement").