AU: Add unit tests for the Terminator class.

terminator.cc

 // Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "update_engine/terminator.h"
 
 #include <cstdlib>
 
 namespace chromeos_update_engine {
 
 volatile sig_atomic_t Terminator::exit_blocked_ = 0;
 volatile sig_atomic_t Terminator::exit_requested_ = 0;
 
 void Terminator::Init() {
+  exit_blocked_ = 0;
+  exit_requested_ = 0;
   signal(SIGTERM, HandleSignal);
 }
 
 void Terminator::Exit() {
   exit(0);
 }
 
 void Terminator::HandleSignal(int signum) {
   if (exit_blocked_ == 0) {
     Exit();
   }
   exit_requested_ = 1;
 }
 
 ScopedTerminatorExitUnblocker::~ScopedTerminatorExitUnblocker() {
   Terminator::set_exit_blocked(false);
   if (Terminator::exit_requested()) {
     Terminator::Exit();
   }
 }
 
 }  // namespace chromeos_update_engine