test_subprocess.py 文件源码

def test_preexec(self):
        # preexec function
        p = subprocess.Popen([sys.executable, "-c",
                              "import sys, os;"
                              "sys.stdout.write(os.getenv('FRUIT'))"],
                             stdout=subprocess.PIPE,
                             preexec_fn=lambda: os.putenv("FRUIT", "apple"))
        self.addCleanup(p.stdout.close)
        self.assertEqual(p.stdout.read(), "apple")