Introduce the ability to wait for the watcher process to initialize.

chrome/app/chrome_watcher_client_unittest_win.cc

+// Copyright 2015 The Chromium 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 "chrome/app/chrome_watcher_client_win.h"
+
+#include <windows.h>
+#include <string>
+#include "base/base_switches.h"
+#include "base/bind.h"
+#include "base/command_line.h"
+#include "base/logging.h"
+#include "base/process/process_handle.h"
+#include "base/strings/string16.h"
+#include "base/strings/string_number_conversions.h"
+#include "base/synchronization/waitable_event.h"
+#include "base/test/multiprocess_test.h"
+#include "base/threading/simple_thread.h"
+#include "base/time/time.h"
+#include "base/win/scoped_handle.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "testing/multiprocess_func_list.h"
+
+namespace {
+
+const char kParentHandle[] = "parent-handle";
+const char kEventHandle[] = "event-handle";
+
+const base::char16 kExitEventName[] = L"ChromeWatcherClientTestFailEvent";
+const base::char16 kInitializeEventName[] = L"ChromeWatcherClientTestFailEvent";
+
+base::win::ScopedHandle InterpretHandleSwitch(base::CommandLine& cmd_line,
+                                              const char* switch_name) {
+  std::string str_handle =
+      cmd_line.GetSwitchValueASCII(switch_name);
+  if (str_handle.empty()) {
+    LOG(ERROR) << "Switch " << switch_name << " unexpectedly absent.";
+    return base::win::ScopedHandle();
+  }
+
+  unsigned int_handle = 0;
+  if (!base::StringToUint(str_handle, &int_handle)) {
+    LOG(ERROR) << "Switch " << switch_name << " has invalid value "
+               << str_handle;
+    return base::win::ScopedHandle();
+  }
+
+  return base::win::ScopedHandle(
+      reinterpret_cast<base::ProcessHandle>(int_handle));
+}
+
+// Simulates a Chrome watcher process. Exits when the global event
+// kExitEventName is signaled. Signals the "on initialized" event (passed on the
+// command-line) when the global event kInitializeEventName is signaled.
+MULTIPROCESS_TEST_MAIN(ChromeWatcherClientTestProcess) {
+  base::CommandLine* cmd_line = base::CommandLine::ForCurrentProcess();
+  base::win::ScopedHandle exit_event(
+      ::CreateEvent(NULL, FALSE, FALSE, kExitEventName));

[Sigurður Ásgeirsson, 2015/01/29 16:59:56]

I think this will create flakes on parallel tests. Better to inherit the handle
or provide a unique name with a flag or environment variable, or by parent
process pid, or some such.

[erikwright (departed), 2015/01/30 20:39:57]

Done.

+  if (!exit_event.IsValid()) {
+    LOG(ERROR) << "Failed to create event named " << kExitEventName;
+    return 1;
+  }
+
+  base::win::ScopedHandle initialize_event(
+      ::CreateEvent(NULL, FALSE, FALSE, kInitializeEventName));

[Sigurður Ásgeirsson, 2015/01/29 16:59:56]

ditto

[erikwright (departed), 2015/01/30 20:39:57]

Done.

+  if (!initialize_event.IsValid()) {
+    LOG(ERROR) << "Failed to create event named " << kInitializeEventName;
+    return 1;
+  }
+
+  base::win::ScopedHandle parent_process(
+      InterpretHandleSwitch(*cmd_line, kParentHandle));
+  if (!parent_process.IsValid())
+    return 1;
+
+  base::win::ScopedHandle on_initialized_event(
+      InterpretHandleSwitch(*cmd_line, kEventHandle));
+  if (!on_initialized_event.IsValid())
+    return 1;
+
+  while (true) {
+    // We loop as a convenient way to continue waiting for the exit_event after
+    // the initialize_event is signaled. We expect to get initialize_event zero
+    // or one times before exit_event, never more.
+    HANDLE handles[] = {exit_event.Get(), initialize_event.Get()};
+    DWORD result =
+        ::WaitForMultipleObjects(arraysize(handles), handles, FALSE, INFINITE);
+    switch (result) {
+      case WAIT_OBJECT_0:
+        // exit_event
+        return 0;
+      case WAIT_OBJECT_0 + 1:
+        // initialize_event
+        ::SetEvent(on_initialized_event.Get());
+        break;
+      case WAIT_FAILED:
+        PLOG(ERROR) << "Unexpected failure in WaitForMultipleObjects.";
+        return 1;
+      default:
+        NOTREACHED() << "Unexpected result from WaitForMultipleObjects: "
+                     << result;
+        return 1;
+    }
+  }
+}
+
+// Returns a command line to launch back into ChromeWatcherClientTestProcess.
+base::CommandLine GenerateCommandLine(HANDLE on_initialized_event,
+                                      HANDLE parent_handle) {
+  base::CommandLine ret = base::GetMultiProcessTestChildBaseCommandLine();
+
+  ret.AppendSwitchASCII(switches::kTestChildProcess, "VerifyParentHandle");
+  ret.AppendSwitchASCII(
+      kEventHandle,
+      base::UintToString(reinterpret_cast<unsigned int>(parent_handle)));
+  ret.AppendSwitchASCII(
+      kParentHandle,
+      base::UintToString(reinterpret_cast<unsigned int>(parent_handle)));
+  return ret;
+}
+
+// Implements a thread to launch the ChromeWatcherClient and block on
+// WaitForInitialization. Provides various helpers to interact with the
+// ChromeWatcherClient.
+class ChromeWatcherClientThread : public base::SimpleThread {
+ public:
+  ChromeWatcherClientThread()
+      : client_(base::Bind(&GenerateCommandLine)),
+        complete_(false, false),
+        result_(false),
+        SimpleThread("ChromeWatcherClientTest thread") {}
+
+  // Waits up to |timeout| for the call to WaitForInitialization to complete. If
+  // it does, sets |result| to the return value of WaitForInitialization and
+  // returns true. Otherwise returns false.
+  bool WaitForResultWithTimeout(const base::TimeDelta& timeout, bool* result) {
+    if (!complete_.TimedWait(timeout))
+      return false;
+    *result = result_;
+    return true;
+  }
+
+  // Waits indefinitely for the call to WaitForInitialization to complete.
+  // Returns the return value of WaitForInitialization.
+  bool WaitForResult() {
+    complete_.Wait();
+    return result_;
+  }
+
+  ChromeWatcherClient& client() { return client_; }
+
+  // base::SimpleThread implementation.
+  void Run() override {
+    result_ = client_.LaunchWatcher();
+    if (result_)
+      result_ = client_.WaitForInitialization();
+    complete_.Signal();
+  }
+
+ private:
+  // The instance under test.
+  ChromeWatcherClient client_;
+  // Signaled when WaitForInitialization returns.
+  base::WaitableEvent complete_;
+  // The return value of WaitForInitialization.
+  bool result_;
+
+  DISALLOW_COPY_AND_ASSIGN(ChromeWatcherClientThread);
+};
+
+}  // namespace
+
+class ChromeWatcherClientTest : public testing::Test {
+ protected:
+  // Sends a signal to the simulated watcher process to exit. Returns true if
+  // successful.
+  bool SignalExit() { return FALSE != ::SetEvent(exit_event_.Get()); }
+
+  // Sends a signal to the simulated watcher process to signal its
+  // "initialization". Returns true if successful.
+  bool SignalInitialize() {
+    return FALSE != ::SetEvent(initialize_event_.Get());
+  }
+
+  // The helper thread, which also provides access to the ChromeWatcherClient.
+  ChromeWatcherClientThread& thread() { return thread_; }
+
+  // testing::Test implementation.
+  void SetUp() override {
+    exit_event_.Set(::CreateEvent(NULL, FALSE, FALSE, kExitEventName));
+    ASSERT_TRUE(exit_event_.IsValid());
+    initialize_event_.Set(
+        ::CreateEvent(NULL, FALSE, FALSE, kInitializeEventName));
+    ASSERT_TRUE(initialize_event_.IsValid());
+  }
+
+  void TearDown() override {
+    if (thread_.client().launched())
+      thread_.client().TerminateWatcher(99);
+    thread_.Join();
+  }
+
+ private:
+  // Used to launch and block on the Chrome watcher process in a background
+  // thread.
+  ChromeWatcherClientThread thread_;
+  // Used to signal the Chrome watcher process to exit.
+  base::win::ScopedHandle exit_event_;
+  // Used to signal the Chrome watcher process to signal its own
+  // initialization..
+  base::win::ScopedHandle initialize_event_;
+};
+
+TEST_F(ChromeWatcherClientTest, SuccessTest) {
+  thread().Start();
+  bool result = false;
+  // Give a broken implementation a chance to exit unexpectedly.
+  ASSERT_FALSE(thread().WaitForResultWithTimeout(
+      base::TimeDelta::FromMilliseconds(100), &result));
+  ASSERT_TRUE(SignalInitialize());
+  ASSERT_TRUE(thread().WaitForResult());
+  // The watcher should still be running. Give a broken implementation a chance
+  // to exit unexpectedly, then kill it. That the returned exit code is what we
+  // requested proves that the process was still running.
+  ASSERT_FALSE(thread().WaitForResultWithTimeout(
+      base::TimeDelta::FromMilliseconds(100), &result));
+  ASSERT_EQ(99, thread().client().TerminateWatcher(99));
+}
+
+TEST_F(ChromeWatcherClientTest, FailureTest) {
+  thread().Start();
+  bool result = false;
+  // Give a broken implementation a chance to exit unexpectedly.
+  ASSERT_FALSE(thread().WaitForResultWithTimeout(
+      base::TimeDelta::FromMilliseconds(100), &result));
+  ASSERT_TRUE(SignalExit());
+  ASSERT_FALSE(thread().WaitForResult());
+  // The exit code will not be as requested since the process exited "normally".
+  ASSERT_EQ(0, thread().client().TerminateWatcher(99));
+}