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// 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 "components/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 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);
// We don't use the descriptor here anyways so it's ok to pass -1.
base::FieldTrialList::CreateTrialsFromCommandLine(
*base::CommandLine::ForCurrentProcess(), "field_trial_handle_switch", -1);
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(),
"single_process");
// 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 variations
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