import time
import os
import thread
import unittest
import sys


class TestForkInThread(unittest.TestCase):
    def setUp(self):
        self.read_fd, self.write_fd = os.pipe()
    
    def test_forkinthread(self):
        def thread1():
            try:
                pid = os.fork() # fork in a thread
            except RuntimeError:
                sys.exit(0) # exit the child
                
            if pid == 0: # child
                os.close(self.read_fd)
                os.write(self.write_fd, "OK")
                sys.exit(0)
            else: # parent
                os.close(self.write_fd)

        thread.start_new_thread(thread1, ())
        self.assertEqual(os.read(self.read_fd, 2), "OK", "Unable to fork() in thread")
        
    def tearDown(self):
        try:
            os.close(self.read_fd)
        except OSError:
            pass
            
        try:
            os.close(self.write_fd)
        except OSError:
            pass
                    
if __name__ == "__main__":
    unittest.main()