Field trial synchronization to PPAPI process.

chrome/common/variations/child_process_field_trial_syncer_unittest.cc

-// Copyright 2016 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/common/variations/child_process_field_trial_syncer.h"
-
-#include <string>
-#include <utility>
-#include <vector>
-
-#include "base/base_switches.h"
-#include "base/command_line.h"
-#include "base/message_loop/message_loop.h"
-#include "base/metrics/field_trial.h"
-#include "base/run_loop.h"
-#include "testing/gtest/include/gtest/gtest.h"
-
-namespace chrome_variations {
-
-namespace {
-
-// TestFieldTrialObserver to listen to be notified by the child process syncer.
-class TestFieldTrialObserver : public base::FieldTrialList::Observer {
- public:
-  TestFieldTrialObserver() {}
-  ~TestFieldTrialObserver() override {}
-
-  // base::FieldTrial::Observer:
-  void OnFieldTrialGroupFinalized(const std::string& trial_name,
-                                  const std::string& group_name) override {
-    observed_entries_.push_back(std::make_pair(trial_name, group_name));
-  }
-
-  size_t observed_entries_count() const { return observed_entries_.size(); }
-
-  std::pair<std::string, std::string> get_observed_entry(int i) const {
-    return observed_entries_[i];
-  }
-
- private:
-  std::vector<std::pair<std::string, std::string>> observed_entries_;
-
-  DISALLOW_COPY_AND_ASSIGN(TestFieldTrialObserver);
-};
-
-// Needed because make_pair("a", "b") doesn't convert to std::string pair.
-std::pair<std::string, std::string> MakeStringPair(const std::string& a,
-                                                   const std::string& b) {
-  return std::make_pair(a, b);
-}
-
-}  // namespace
-
-TEST(ChildProcessFieldTrialSyncerTest, FieldTrialState) {
-  base::MessageLoop message_loop;
-  base::FieldTrialList field_trial_list(nullptr);
-  base::FieldTrialList::CreateTrialsFromCommandLine(
-     *base::CommandLine::ForCurrentProcess(), "field_trial_handle_switch");
-
-  base::FieldTrial* trial1 = base::FieldTrialList::CreateFieldTrial("A", "G1");
-  base::FieldTrial* trial2 = base::FieldTrialList::CreateFieldTrial("B", "G2");
-  base::FieldTrial* trial3 = base::FieldTrialList::CreateFieldTrial("C", "G3");
-  // Activate trial3 before command line is produced.
-  trial1->group();
-
-  std::string states_string;
-  base::FieldTrialList::AllStatesToString(&states_string);
-
-  base::CommandLine::ForCurrentProcess()->AppendSwitchASCII(
-      switches::kForceFieldTrials, states_string);
-  EXPECT_EQ("*A/G1/B/G2/C/G3/", states_string);
-
-  // Active trial 2 before creating the syncer.
-  trial2->group();
-
-  TestFieldTrialObserver observer;
-  ChildProcessFieldTrialSyncer syncer(&observer);
-  syncer.InitFieldTrialObserving(*base::CommandLine::ForCurrentProcess());
-
-  // The observer should be notified of activated entries that were not activate
-  // on the command line. In this case, trial 2. (Trial 1 was already active via
-  // command line and so its state shouldn't be notified.)
-  ASSERT_EQ(1U, observer.observed_entries_count());
-  EXPECT_EQ(MakeStringPair("B", "G2"), observer.get_observed_entry(0));
-
-  // Now, activate trial 3, which should also get reflected.
-  trial3->group();
-  // Notifications from field trial activation actually happen via posted tasks,
-  // so invoke the run loop.
-  base::RunLoop().RunUntilIdle();
-
-  ASSERT_EQ(2U, observer.observed_entries_count());
-  EXPECT_EQ(MakeStringPair("C", "G3"), observer.get_observed_entry(1));
-}
-
-}  // namespace chrome_variations