'Replace L{process} os, fcntl, sys, switchUID, fdesc and pty modules
with the mock class L{MockOS}.'

def setUp(self):

    if gc.isenabled():
        self.addCleanup(gc.enable)
    else:
        self.addCleanup(gc.disable)
    self.mockos = MockOS()
    self.mockos.euid = 1236
    self.mockos.egid = 1234
    self.patch(process, 'os', self.mockos)
    self.patch(process, 'fcntl', self.mockos)
    self.patch(process, 'sys', self.mockos)
    self.patch(process, 'switchUID', self.mockos.switchUID)
    self.patch(process, 'fdesc', self.mockos)
    self.patch(process.Process, 'processReaderFactory', DumbProcessReader)
    self.patch(process.Process, 'processWriterFactory', DumbProcessWriter)
    self.patch(process, 'pty', self.mockos)
    self.mocksig = MockSignal()
    self.patch(process, 'signal', self.mocksig)
