// startInstance starts a new instance for the given machine.
func (s *FirewallerSuite) startInstance(c *C, m *state.Machine) environs.Instance {
inst, err := s.Conn.Environ.StartInstance(m.Id(), testing.InvalidStateInfo(m.Id()), nil)
c.Assert(err, IsNil)
err = m.SetInstanceId(inst.Id())
c.Assert(err, IsNil)
return inst
}