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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.
#ifndef BASE_TEST_SCOPED_FEATURE_LIST_H_
#define BASE_TEST_SCOPED_FEATURE_LIST_H_
#include <map>
#include <memory>
#include <string>
#include <vector>
#include "base/feature_list.h"
#include "base/memory/ref_counted.h"
#include "base/metrics/field_trial.h"
namespace base {
namespace test {
// ScopedFeatureList resets the global FeatureList instance to a new empty
// instance and restores the original instance upon destruction.
// Note: Re-using the same object is not allowed. To reset the feature
// list and initialize it anew, destroy an existing scoped list and init
// a new one.
//
// ScopedFeatureList needs to be initialized (via one of Init... methods)
// before running code that inspects the state of features. In practice this
// means:
// - In browser tests, one of Init... methods should be called from the
// overriden ::testing::Test::SetUp method. For example:
// void SetUp() override {
// scoped_feature_list_.InitAndEnableFeature(features::kMyFeatureHere);
// InProcessBrowserTest::SetUp();
// }
class ScopedFeatureList final {
public:
ScopedFeatureList();
~ScopedFeatureList();
// WARNING: This method will reset any globally configured features to their
// default values, which can hide feature interaction bugs. Please use
// sparingly. https://crbug.com/713390
// Initializes and registers a FeatureList instance with no overrides.
void Init();
// WARNING: This method will reset any globally configured features to their
// default values, which can hide feature interaction bugs. Please use
// sparingly. https://crbug.com/713390
// Initializes and registers the given FeatureList instance.
void InitWithFeatureList(std::unique_ptr<FeatureList> feature_list);
// WARNING: This method will reset any globally configured features to their
// default values, which can hide feature interaction bugs. Please use
// sparingly. https://crbug.com/713390
// Initializes and registers a FeatureList instance with only the given
// enabled and disabled features (comma-separated names).
void InitFromCommandLine(const std::string& enable_features,
const std::string& disable_features);
// Initializes and registers a FeatureList instance based on present
// FeatureList and overridden with the given enabled and disabled features.
// Any feature overrides already present in the global FeatureList will
// continue to apply, unless they conflict with the overrides passed into this
// method. This is important for testing potentially unexpected feature
// interactions.
void InitWithFeatures(const std::vector<Feature>& enabled_features,
const std::vector<Feature>& disabled_features);
// Initializes and registers a FeatureList instance based on present
// FeatureList and overridden with single enabled feature.
void InitAndEnableFeature(const Feature& feature);
// Initializes and registers a FeatureList instance based on present
// FeatureList and overridden with single enabled feature and associated field
// trial parameters.
// Note: this creates a scoped global field trial list if there is not
// currently one.
void InitAndEnableFeatureWithParameters(
const Feature& feature,
const std::map<std::string, std::string>& feature_parameters);
// Initializes and registers a FeatureList instance based on present
// FeatureList and overridden with single disabled feature.
void InitAndDisableFeature(const Feature& feature);
// Initializes and registers a FeatureList instance based on present
// FeatureList and overriden with a single feature either enabled or
// disabled depending on |enabled|.
void InitWithFeatureState(const Feature& feature, bool enabled);
private:
// Initializes and registers a FeatureList instance based on present
// FeatureList and overridden with the given enabled and disabled features.
// Any feature overrides already present in the global FeatureList will
// continue to apply, unless they conflict with the overrides passed into this
// method.
// Field trials will apply to the enabled features, in the same order. The
// number of trials must be less (or equal) than the number of enabled
// features.
// Trials are expected to outlive the ScopedFeatureList.
void InitWithFeaturesAndFieldTrials(
const std::vector<Feature>& enabled_features,
const std::vector<FieldTrial*>& trials_for_enabled_features,
const std::vector<Feature>& disabled_features);
// Initializes and registers a FeatureList instance based on present
// FeatureList and overridden with single enabled feature and associated field
// trial override.
// |trial| is expected to outlive the ScopedFeatureList.
void InitAndEnableFeatureWithFieldTrialOverride(const Feature& feature,
FieldTrial* trial);
bool init_called_ = false;
std::unique_ptr<FeatureList> original_feature_list_;
scoped_refptr<FieldTrial> field_trial_override_;
std::unique_ptr<base::FieldTrialList> field_trial_list_;
DISALLOW_COPY_AND_ASSIGN(ScopedFeatureList);
};
} // namespace test
} // namespace base
#endif // BASE_TEST_SCOPED_FEATURE_LIST_H_