chromium/components/performance_manager/test_support/resource_attribution/measurement_delegates.h

// Copyright 2023 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef COMPONENTS_PERFORMANCE_MANAGER_TEST_SUPPORT_RESOURCE_ATTRIBUTION_MEASUREMENT_DELEGATES_H_
#define COMPONENTS_PERFORMANCE_MANAGER_TEST_SUPPORT_RESOURCE_ATTRIBUTION_MEASUREMENT_DELEGATES_H_

#include <map>
#include <memory>
#include <optional>
#include <vector>

#include "base/functional/callback_forward.h"
#include "base/memory/safe_ref.h"
#include "base/memory/weak_ptr.h"
#include "base/time/time.h"
#include "base/types/expected.h"
#include "base/types/pass_key.h"
#include "components/performance_manager/public/resource_attribution/cpu_measurement_delegate.h"
#include "components/performance_manager/public/resource_attribution/memory_measurement_delegate.h"

namespace performance_manager {
class ProcessNode;
}

namespace resource_attribution {

class SimulatedCPUMeasurementDelegate;

// The proportion of CPU used over time as a fraction, on the same scale as
// ProcessMetrics::GetPlatformIndependentCPUUsage: 0% to 100% *
// SysInfo::NumberOfProcessors().
//
// Since tests should be independent of the number of processors, it's usually
// convenient to use a range of 0.0 to 1.0 (for 100%), simulating a
// single-processor system. But if the code under test scales CPU measurements
// by SysInfo::NumberOfProcessors(), it's better to set the simulated usage to
// SysInfo::NumberOfProcessors() * a fraction, so that the code under test
// gets the same results after scaling on every system.
SimulatedCPUUsage;

// A factory that manages SimulatedCPUMeasurementDelegate instances. Embed an
// instance of this in a unit test, and pass it to
// CPUMeasurementDelegate::SetDelegateFactoryForTesting(). The caller must
// ensure that the SimulatedCPUMeasurementDelegateFactory outlives all callers
// of CreateDelegateForProcess().
class SimulatedCPUMeasurementDelegateFactory final
    : public CPUMeasurementDelegate::Factory { … };

// State of a simulated process for CPU measurements.
class SimulatedCPUMeasurementDelegate final : public CPUMeasurementDelegate { … };

// A factory that manages FakeMemoryMeasurementDelegate instances. Embed an
// instance of this in a unit test, and pass it to
// MemoryMeasurementDelegate::SetDelegateFactoryForTesting(). The caller must
// ensure that the FakeMemoryMeasurementDelegateFactory outlives all callers
// of CreateDelegate().
class FakeMemoryMeasurementDelegateFactory final
    : public MemoryMeasurementDelegate::Factory { … };

// A MemoryMeasurementDelegate that returns fake results.
class FakeMemoryMeasurementDelegate final : public MemoryMeasurementDelegate { … };

}  // namespace resource_attribution

#endif  // COMPONENTS_PERFORMANCE_MANAGER_TEST_SUPPORT_RESOURCE_ATTRIBUTION_MEASUREMENT_DELEGATES_H_