AU: Add unit tests for the Terminator class.

Also, improve the implementation so that the Terminator can be initialized
multiple times.

BUG=6243
TEST=unit tests

Change-Id: I8d7f1a2007ac28f8c79506f46d628654413b6607

Review URL: http://codereview.chromium.org/5104007
diff --git a/SConstruct b/SConstruct
index 97cc6e3..d036745 100644
--- a/SConstruct
+++ b/SConstruct
@@ -308,6 +308,7 @@
                             split_file_writer_unittest.cc
                             subprocess_unittest.cc
                             tarjan_unittest.cc
+                            terminator_unittest.cc
                             test_utils.cc
                             topological_sort_unittest.cc
                             update_attempter_unittest.cc
diff --git a/terminator.cc b/terminator.cc
index 1d33e32..9165afb 100644
--- a/terminator.cc
+++ b/terminator.cc
@@ -12,6 +12,8 @@
 volatile sig_atomic_t Terminator::exit_requested_ = 0;
 
 void Terminator::Init() {
+  exit_blocked_ = 0;
+  exit_requested_ = 0;
   signal(SIGTERM, HandleSignal);
 }
 
diff --git a/terminator.h b/terminator.h
index 1c014ea..b3fdba6 100644
--- a/terminator.h
+++ b/terminator.h
@@ -7,6 +7,8 @@
 
 #include <signal.h>
 
+#include <gtest/gtest_prod.h>  // for FRIEND_TEST
+
 namespace chromeos_update_engine {
 
 // A class allowing graceful delayed exit.
@@ -21,6 +23,7 @@
   // Set to true if the terminator should block termination requests in an
   // attempt to block exiting.
   static void set_exit_blocked(bool block) { exit_blocked_ = block ? 1 : 0; }
+  static bool exit_blocked() { return exit_blocked_ != 0; }
 
   // Returns true if the system is trying to terminate the process, false
   // otherwise. Returns true only if exit was blocked when the termination
@@ -28,6 +31,9 @@
   static bool exit_requested() { return exit_requested_ != 0; }
 
  private:
+  FRIEND_TEST(TerminatorTest, HandleSignalTest);
+  FRIEND_TEST(TerminatorDeathTest, ScopedTerminatorExitUnblockerExitTest);
+
   // The signal handler.
   static void HandleSignal(int signum);
 
diff --git a/terminator_unittest.cc b/terminator_unittest.cc
new file mode 100644
index 0000000..e1fb573
--- /dev/null
+++ b/terminator_unittest.cc
@@ -0,0 +1,69 @@
+// 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 <gtest/gtest.h>
+#include <gtest/gtest-spi.h>
+
+#include "update_engine/terminator.h"
+
+using std::string;
+using testing::ExitedWithCode;
+
+namespace chromeos_update_engine {
+
+class TerminatorTest : public ::testing::Test {
+ protected:
+  virtual void SetUp() {
+    Terminator::Init();
+    ASSERT_FALSE(Terminator::exit_blocked());
+    ASSERT_FALSE(Terminator::exit_requested());
+  }
+};
+
+typedef TerminatorTest TerminatorDeathTest;
+
+namespace {
+void UnblockExitThroughUnblocker() {
+  ScopedTerminatorExitUnblocker unblocker = ScopedTerminatorExitUnblocker();
+}
+
+void RaiseSIGTERM() {
+  ASSERT_EXIT(raise(SIGTERM), ExitedWithCode(0), "");
+}
+}  // namespace {}
+
+TEST_F(TerminatorTest, HandleSignalTest) {
+  Terminator::set_exit_blocked(true);
+  Terminator::HandleSignal(SIGTERM);
+  ASSERT_TRUE(Terminator::exit_requested());
+}
+
+TEST_F(TerminatorTest, ScopedTerminatorExitUnblockerTest) {
+  Terminator::set_exit_blocked(true);
+  ASSERT_TRUE(Terminator::exit_blocked());
+  ASSERT_FALSE(Terminator::exit_requested());
+  UnblockExitThroughUnblocker();
+  ASSERT_FALSE(Terminator::exit_blocked());
+  ASSERT_FALSE(Terminator::exit_requested());
+}
+
+TEST_F(TerminatorDeathTest, ExitTest) {
+  ASSERT_EXIT(Terminator::Exit(), ExitedWithCode(0), "");
+  Terminator::set_exit_blocked(true);
+  ASSERT_EXIT(Terminator::Exit(), ExitedWithCode(0), "");
+}
+
+TEST_F(TerminatorDeathTest, RaiseSignalTest) {
+  RaiseSIGTERM();
+  Terminator::set_exit_blocked(true);
+  EXPECT_FATAL_FAILURE(RaiseSIGTERM(), "");
+}
+
+TEST_F(TerminatorDeathTest, ScopedTerminatorExitUnblockerExitTest) {
+  Terminator::set_exit_blocked(true);
+  Terminator::exit_requested_ = 1;
+  ASSERT_EXIT(UnblockExitThroughUnblocker(), ExitedWithCode(0), "");
+}
+
+}  // namespace chromeos_update_engine