src/trace_redaction/redact_sched_switch_unittest.cc - third_party/perfetto - Git at Google

 /*
  * Copyright (C) 2024 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 #include "src/trace_redaction/redact_sched_switch.h"
 #include "src/base/test/status_matchers.h"
 #include "test/gtest_and_gmock.h"

 #include "protos/perfetto/trace/ftrace/ftrace_event.gen.h"
 #include "protos/perfetto/trace/ftrace/ftrace_event_bundle.gen.h"
 #include "protos/perfetto/trace/ftrace/sched.gen.h"
 #include "protos/perfetto/trace/trace.gen.h"
 #include "protos/perfetto/trace/trace_packet.gen.h"

 namespace perfetto::trace_redaction {

 namespace {

 constexpr uint64_t kUidA = 1;
 constexpr uint64_t kUidB = 2;
 constexpr uint64_t kUidC = 3;

 constexpr int32_t kNoParent = 10;
 constexpr int32_t kPidA = 11;
 constexpr int32_t kPidB = 12;

 constexpr int32_t kCpuA = 0;

 constexpr uint64_t kFullStep = 1000;
 constexpr uint64_t kTimeA = 0;
 constexpr uint64_t kTimeB = kFullStep;

 constexpr auto kCommA = "comm-a";
 constexpr auto kCommB = "comm-b";
 constexpr auto kCommNone = "";

 class NegatePid : public SchedSwitchTransform {
  public:
   base::Status Transform(const Context&,
                          uint64_t,
                          int32_t,
                          int32_t* pid,
                          std::string*) const override {
     *pid = -(*pid);
     return base::OkStatus();
   }
 };

 }  // namespace

 class RedactSchedSwitchFtraceEventTest : public testing::Test {
  protected:
   void SetUp() override {
     // Create a packet where two pids are swapping back-and-forth.
     auto* bundle = packet_.mutable_ftrace_events();
     bundle->set_cpu(kCpuA);

     {
       auto* event = bundle->add_event();

       event->set_timestamp(kTimeA);
       event->set_pid(kPidA);

       auto* sched_switch = event->mutable_sched_switch();
       sched_switch->set_prev_comm(kCommA);
       sched_switch->set_prev_pid(kPidA);
       sched_switch->set_prev_prio(0);
       sched_switch->set_prev_state(0);
       sched_switch->set_next_comm(kCommB);
       sched_switch->set_next_pid(kPidB);
       sched_switch->set_next_prio(0);
     }

     {
       auto* event = bundle->add_event();

       event->set_timestamp(kTimeB);
       event->set_pid(kPidB);

       auto* sched_switch = event->mutable_sched_switch();
       sched_switch->set_prev_comm(kCommB);
       sched_switch->set_prev_pid(kPidB);
       sched_switch->set_prev_prio(0);
       sched_switch->set_prev_state(0);
       sched_switch->set_next_comm(kCommA);
       sched_switch->set_next_pid(kPidA);
       sched_switch->set_next_prio(0);
     }

     // PID A and PID B need to be attached to different packages (UID) so that
     // its possible to include one but not the other.
     context_.timeline = std::make_unique<ProcessThreadTimeline>();
     context_.timeline->Append(
         ProcessThreadTimeline::Event::Open(kTimeA, kPidA, kNoParent, kUidA));
     context_.timeline->Append(
         ProcessThreadTimeline::Event::Open(kTimeA, kPidB, kNoParent, kUidB));
     context_.timeline->Sort();
   }

   protos::gen::TracePacket packet_;
   Context context_;
 };

 // In this case, the target uid will be UID A. That means the comm values for
 // PID B should be removed, and the comm values for PID A should remain.
 TEST_F(RedactSchedSwitchFtraceEventTest, KeepsTargetCommValues) {
   RedactSchedSwitchHarness redact;
   redact.emplace_transform<ClearComms>();

   context_.package_uid = kUidA;

   auto packet_buffer = packet_.SerializeAsString();

   ASSERT_OK(redact.Transform(context_, &packet_buffer));

   protos::gen::TracePacket packet;
   ASSERT_TRUE(packet.ParseFromString(packet_buffer));

   const auto& bundle = packet.ftrace_events();
   const auto& events = bundle.event();

   ASSERT_EQ(events.size(), 2u);

   ASSERT_EQ(events[0].sched_switch().prev_pid(), kPidA);
   ASSERT_EQ(events[0].sched_switch().prev_comm(), kCommA);

   ASSERT_EQ(events[0].sched_switch().next_pid(), kPidB);
   ASSERT_EQ(events[0].sched_switch().next_comm(), kCommNone);

   ASSERT_EQ(events[1].sched_switch().prev_pid(), kPidB);
   ASSERT_EQ(events[1].sched_switch().prev_comm(), kCommNone);

   ASSERT_EQ(events[1].sched_switch().next_pid(), kPidA);
   ASSERT_EQ(events[1].sched_switch().next_comm(), kCommA);
 }

 // This case is very similar to the "some are connected", expect that it
 // verifies all comm values will be removed when testing against an unused
 // uid.
 TEST_F(RedactSchedSwitchFtraceEventTest, RemovesAllCommsIfPackageDoesntExist) {
   RedactSchedSwitchHarness redact;
   redact.emplace_transform<ClearComms>();

   context_.package_uid = kUidC;

   auto packet_buffer = packet_.SerializeAsString();

   ASSERT_OK(redact.Transform(context_, &packet_buffer));

   protos::gen::TracePacket packet;
   ASSERT_TRUE(packet.ParseFromString(packet_buffer));

   const auto& bundle = packet.ftrace_events();
   const auto& events = bundle.event();

   ASSERT_EQ(events.size(), 2u);

   ASSERT_EQ(events[0].sched_switch().prev_comm(), kCommNone);
   ASSERT_EQ(events[0].sched_switch().next_comm(), kCommNone);

   ASSERT_EQ(events[1].sched_switch().prev_comm(), kCommNone);
   ASSERT_EQ(events[1].sched_switch().next_comm(), kCommNone);
 }

 class RedactCompactSchedSwitchTest : public testing::Test {
  protected:
   void SetUp() override {
     // PID A and PID B need to be attached to different packages (UID) so that
     // its possible to include one but not the other.
     context_.timeline = std::make_unique<ProcessThreadTimeline>();
     context_.timeline->Append(
         ProcessThreadTimeline::Event::Open(kTimeA, kPidA, kNoParent, kUidA));
     context_.timeline->Append(
         ProcessThreadTimeline::Event::Open(kTimeA, kPidB, kNoParent, kUidB));
     context_.timeline->Sort();

     auto* bundle = packet_.mutable_ftrace_events();
     bundle->set_cpu(kCpuA);  // All switch events occur on this CPU

     compact_sched = bundle->mutable_compact_sched();

     compact_sched->add_intern_table(kCommA);
     compact_sched->add_intern_table(kCommB);
   }

   void AddSwitchEvent(uint64_t ts,
                       int32_t next_pid,
                       int32_t prev_state,
                       int32_t prio,
                       uint32_t comm) {
     compact_sched->add_switch_timestamp(ts);
     compact_sched->add_switch_next_pid(next_pid);
     compact_sched->add_switch_prev_state(prev_state);
     compact_sched->add_switch_next_prio(prio);
     compact_sched->add_switch_next_comm_index(comm);
   }

   protos::gen::TracePacket packet_;
   protos::gen::FtraceEventBundle::CompactSched* compact_sched;

   Context context_;
 };

 TEST_F(RedactCompactSchedSwitchTest, KeepsTargetCommValues) {
   uint32_t kCommIndexA = 0;
   uint32_t kCommIndexB = 1;

   // The new entry will be appended to the table. Another primitive can be used
   // to reduce the intern string table.
   uint32_t kCommIndexNone = 2;

   AddSwitchEvent(kTimeA, kPidA, 0, 0, kCommIndexA);
   AddSwitchEvent(kTimeB, kPidB, 0, 0, kCommIndexB);

   context_.package_uid = kUidA;

   auto packet_buffer = packet_.SerializeAsString();

   RedactSchedSwitchHarness redact;
   redact.emplace_transform<ClearComms>();

   ASSERT_OK(redact.Transform(context_, &packet_buffer));

   protos::gen::TracePacket packet;
   ASSERT_TRUE(packet.ParseFromString(packet_buffer));

   const auto& bundle = packet.ftrace_events();
   ASSERT_TRUE(bundle.has_compact_sched());

   const auto& compact_sched = bundle.compact_sched();

   // A new entry (empty string) should have been added to the table.
   ASSERT_EQ(compact_sched.intern_table_size(), 3);
   ASSERT_EQ(compact_sched.intern_table().back(), kCommNone);

   ASSERT_EQ(compact_sched.switch_next_comm_index_size(), 2);
   ASSERT_EQ(compact_sched.switch_next_comm_index().at(0), kCommIndexA);
   ASSERT_EQ(compact_sched.switch_next_comm_index().at(1), kCommIndexNone);
 }

 // If two pids use the same comm, but one pid changes, the shared comm should
 // still be available.
 TEST_F(RedactCompactSchedSwitchTest, ChangingSharedCommonRetainsComm) {
   uint32_t kCommIndexA = 0;

   AddSwitchEvent(kTimeA, kPidA, 0, 0, kCommIndexA);
   AddSwitchEvent(kTimeB, kPidB, 0, 0, kCommIndexA);

   context_.package_uid = kUidA;

   auto packet_buffer = packet_.SerializeAsString();

   RedactSchedSwitchHarness redact;
   redact.emplace_transform<ClearComms>();

   ASSERT_OK(redact.Transform(context_, &packet_buffer));

   protos::gen::TracePacket packet;
   ASSERT_TRUE(packet.ParseFromString(packet_buffer));

   const auto& bundle = packet.ftrace_events();
   ASSERT_TRUE(bundle.has_compact_sched());

   const auto& compact_sched = bundle.compact_sched();

   // A new entry should have been appended, but comm A (previously shared)
   // should still exist in the table.
   ASSERT_EQ(compact_sched.intern_table_size(), 3);
   ASSERT_EQ(compact_sched.intern_table().front(), kCommA);
   ASSERT_EQ(compact_sched.intern_table().back(), kCommNone);
 }

 TEST_F(RedactCompactSchedSwitchTest, RemovesAllCommsIfPackageDoesntExist) {
   uint32_t kCommIndexA = 0;
   uint32_t kCommIndexB = 1;

   // The new entry will be appended to the table. Another primitive can be used
   // to reduce the intern string table.
   uint32_t kCommIndexNone = 2;

   AddSwitchEvent(kTimeA, kPidA, 0, 0, kCommIndexA);
   AddSwitchEvent(kTimeB, kPidB, 0, 0, kCommIndexB);

   context_.package_uid = kUidC;

   auto packet_buffer = packet_.SerializeAsString();

   RedactSchedSwitchHarness redact;
   redact.emplace_transform<ClearComms>();

   ASSERT_OK(redact.Transform(context_, &packet_buffer));

   protos::gen::TracePacket packet;
   ASSERT_TRUE(packet.ParseFromString(packet_buffer));

   const auto& bundle = packet.ftrace_events();
   ASSERT_TRUE(bundle.has_compact_sched());

   const auto& compact_sched = bundle.compact_sched();

   // A new entry (empty string) should have been added to the table.
   ASSERT_EQ(compact_sched.intern_table_size(), 3);
   ASSERT_EQ(compact_sched.intern_table().back(), kCommNone);

   ASSERT_EQ(compact_sched.switch_next_comm_index_size(), 2);
   ASSERT_EQ(compact_sched.switch_next_comm_index().at(0), kCommIndexNone);
   ASSERT_EQ(compact_sched.switch_next_comm_index().at(1), kCommIndexNone);
 }

 TEST_F(RedactCompactSchedSwitchTest, CanChangePid) {
   uint32_t kCommIndexA = 0;
   uint32_t kCommIndexB = 1;

   AddSwitchEvent(kTimeA, kPidA, 0, 0, kCommIndexA);
   AddSwitchEvent(kTimeB, kPidB, 0, 0, kCommIndexB);

   context_.package_uid = kUidA;  // This value is not needed to use NegatePid.

   auto packet_buffer = packet_.SerializeAsString();

   RedactSchedSwitchHarness redact;
   redact.emplace_transform<NegatePid>();

   ASSERT_OK(redact.Transform(context_, &packet_buffer));

   protos::gen::TracePacket packet;
   ASSERT_TRUE(packet.ParseFromString(packet_buffer));

   const auto& bundle = packet.ftrace_events();
   ASSERT_TRUE(bundle.has_compact_sched());

   const auto& compact_sched = bundle.compact_sched();

   // The intern table should not change.
   ASSERT_EQ(compact_sched.intern_table_size(), 2);

   ASSERT_EQ(compact_sched.switch_next_pid_size(), 2);
   ASSERT_EQ(compact_sched.switch_next_pid().at(0), -kPidA);
   ASSERT_EQ(compact_sched.switch_next_pid().at(1), -kPidB);
 }

 }  // namespace perfetto::trace_redaction
	/*
	* Copyright (C) 2024 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	#include "src/trace_redaction/redact_sched_switch.h"
	#include "src/base/test/status_matchers.h"
	#include "test/gtest_and_gmock.h"

	#include "protos/perfetto/trace/ftrace/ftrace_event.gen.h"
	#include "protos/perfetto/trace/ftrace/ftrace_event_bundle.gen.h"
	#include "protos/perfetto/trace/ftrace/sched.gen.h"
	#include "protos/perfetto/trace/trace.gen.h"
	#include "protos/perfetto/trace/trace_packet.gen.h"

	namespace perfetto::trace_redaction {

	namespace {

	constexpr uint64_t kUidA = 1;
	constexpr uint64_t kUidB = 2;
	constexpr uint64_t kUidC = 3;

	constexpr int32_t kNoParent = 10;
	constexpr int32_t kPidA = 11;
	constexpr int32_t kPidB = 12;

	constexpr int32_t kCpuA = 0;

	constexpr uint64_t kFullStep = 1000;
	constexpr uint64_t kTimeA = 0;
	constexpr uint64_t kTimeB = kFullStep;

	constexpr auto kCommA = "comm-a";
	constexpr auto kCommB = "comm-b";
	constexpr auto kCommNone = "";

	class NegatePid : public SchedSwitchTransform {
	public:
	base::Status Transform(const Context&,
	uint64_t,
	int32_t,
	int32_t* pid,
	std::string*) const override {
	pid = -(pid);
	return base::OkStatus();
	}
	};

	} // namespace

	class RedactSchedSwitchFtraceEventTest : public testing::Test {
	protected:
	void SetUp() override {
	// Create a packet where two pids are swapping back-and-forth.
	auto* bundle = packet_.mutable_ftrace_events();
	bundle->set_cpu(kCpuA);

	{
	auto* event = bundle->add_event();

	event->set_timestamp(kTimeA);
	event->set_pid(kPidA);

	auto* sched_switch = event->mutable_sched_switch();
	sched_switch->set_prev_comm(kCommA);
	sched_switch->set_prev_pid(kPidA);
	sched_switch->set_prev_prio(0);
	sched_switch->set_prev_state(0);
	sched_switch->set_next_comm(kCommB);
	sched_switch->set_next_pid(kPidB);
	sched_switch->set_next_prio(0);
	}

	{
	auto* event = bundle->add_event();

	event->set_timestamp(kTimeB);
	event->set_pid(kPidB);

	auto* sched_switch = event->mutable_sched_switch();
	sched_switch->set_prev_comm(kCommB);
	sched_switch->set_prev_pid(kPidB);
	sched_switch->set_prev_prio(0);
	sched_switch->set_prev_state(0);
	sched_switch->set_next_comm(kCommA);
	sched_switch->set_next_pid(kPidA);
	sched_switch->set_next_prio(0);
	}

	// PID A and PID B need to be attached to different packages (UID) so that
	// its possible to include one but not the other.
	context_.timeline = std::make_unique<ProcessThreadTimeline>();
	context_.timeline->Append(
	ProcessThreadTimeline::Event::Open(kTimeA, kPidA, kNoParent, kUidA));
	context_.timeline->Append(
	ProcessThreadTimeline::Event::Open(kTimeA, kPidB, kNoParent, kUidB));
	context_.timeline->Sort();
	}

	protos::gen::TracePacket packet_;
	Context context_;
	};

	// In this case, the target uid will be UID A. That means the comm values for
	// PID B should be removed, and the comm values for PID A should remain.
	TEST_F(RedactSchedSwitchFtraceEventTest, KeepsTargetCommValues) {
	RedactSchedSwitchHarness redact;
	redact.emplace_transform<ClearComms>();

	context_.package_uid = kUidA;

	auto packet_buffer = packet_.SerializeAsString();

	ASSERT_OK(redact.Transform(context_, &packet_buffer));

	protos::gen::TracePacket packet;
	ASSERT_TRUE(packet.ParseFromString(packet_buffer));

	const auto& bundle = packet.ftrace_events();
	const auto& events = bundle.event();

	ASSERT_EQ(events.size(), 2u);

	ASSERT_EQ(events[0].sched_switch().prev_pid(), kPidA);
	ASSERT_EQ(events[0].sched_switch().prev_comm(), kCommA);

	ASSERT_EQ(events[0].sched_switch().next_pid(), kPidB);
	ASSERT_EQ(events[0].sched_switch().next_comm(), kCommNone);

	ASSERT_EQ(events[1].sched_switch().prev_pid(), kPidB);
	ASSERT_EQ(events[1].sched_switch().prev_comm(), kCommNone);

	ASSERT_EQ(events[1].sched_switch().next_pid(), kPidA);
	ASSERT_EQ(events[1].sched_switch().next_comm(), kCommA);
	}

	// This case is very similar to the "some are connected", expect that it
	// verifies all comm values will be removed when testing against an unused
	// uid.
	TEST_F(RedactSchedSwitchFtraceEventTest, RemovesAllCommsIfPackageDoesntExist) {
	RedactSchedSwitchHarness redact;
	redact.emplace_transform<ClearComms>();

	context_.package_uid = kUidC;

	auto packet_buffer = packet_.SerializeAsString();

	ASSERT_OK(redact.Transform(context_, &packet_buffer));

	protos::gen::TracePacket packet;
	ASSERT_TRUE(packet.ParseFromString(packet_buffer));

	const auto& bundle = packet.ftrace_events();
	const auto& events = bundle.event();

	ASSERT_EQ(events.size(), 2u);

	ASSERT_EQ(events[0].sched_switch().prev_comm(), kCommNone);
	ASSERT_EQ(events[0].sched_switch().next_comm(), kCommNone);

	ASSERT_EQ(events[1].sched_switch().prev_comm(), kCommNone);
	ASSERT_EQ(events[1].sched_switch().next_comm(), kCommNone);
	}

	class RedactCompactSchedSwitchTest : public testing::Test {
	protected:
	void SetUp() override {
	// PID A and PID B need to be attached to different packages (UID) so that
	// its possible to include one but not the other.
	context_.timeline = std::make_unique<ProcessThreadTimeline>();
	context_.timeline->Append(
	ProcessThreadTimeline::Event::Open(kTimeA, kPidA, kNoParent, kUidA));
	context_.timeline->Append(
	ProcessThreadTimeline::Event::Open(kTimeA, kPidB, kNoParent, kUidB));
	context_.timeline->Sort();

	auto* bundle = packet_.mutable_ftrace_events();
	bundle->set_cpu(kCpuA); // All switch events occur on this CPU

	compact_sched = bundle->mutable_compact_sched();

	compact_sched->add_intern_table(kCommA);
	compact_sched->add_intern_table(kCommB);
	}

	void AddSwitchEvent(uint64_t ts,
	int32_t next_pid,
	int32_t prev_state,
	int32_t prio,
	uint32_t comm) {
	compact_sched->add_switch_timestamp(ts);
	compact_sched->add_switch_next_pid(next_pid);
	compact_sched->add_switch_prev_state(prev_state);
	compact_sched->add_switch_next_prio(prio);
	compact_sched->add_switch_next_comm_index(comm);
	}

	protos::gen::TracePacket packet_;
	protos::gen::FtraceEventBundle::CompactSched* compact_sched;

	Context context_;
	};

	TEST_F(RedactCompactSchedSwitchTest, KeepsTargetCommValues) {
	uint32_t kCommIndexA = 0;
	uint32_t kCommIndexB = 1;

	// The new entry will be appended to the table. Another primitive can be used
	// to reduce the intern string table.
	uint32_t kCommIndexNone = 2;

	AddSwitchEvent(kTimeA, kPidA, 0, 0, kCommIndexA);
	AddSwitchEvent(kTimeB, kPidB, 0, 0, kCommIndexB);

	context_.package_uid = kUidA;

	auto packet_buffer = packet_.SerializeAsString();

	RedactSchedSwitchHarness redact;
	redact.emplace_transform<ClearComms>();

	ASSERT_OK(redact.Transform(context_, &packet_buffer));

	protos::gen::TracePacket packet;
	ASSERT_TRUE(packet.ParseFromString(packet_buffer));

	const auto& bundle = packet.ftrace_events();
	ASSERT_TRUE(bundle.has_compact_sched());

	const auto& compact_sched = bundle.compact_sched();

	// A new entry (empty string) should have been added to the table.
	ASSERT_EQ(compact_sched.intern_table_size(), 3);
	ASSERT_EQ(compact_sched.intern_table().back(), kCommNone);

	ASSERT_EQ(compact_sched.switch_next_comm_index_size(), 2);
	ASSERT_EQ(compact_sched.switch_next_comm_index().at(0), kCommIndexA);
	ASSERT_EQ(compact_sched.switch_next_comm_index().at(1), kCommIndexNone);
	}

	// If two pids use the same comm, but one pid changes, the shared comm should
	// still be available.
	TEST_F(RedactCompactSchedSwitchTest, ChangingSharedCommonRetainsComm) {
	uint32_t kCommIndexA = 0;

	AddSwitchEvent(kTimeA, kPidA, 0, 0, kCommIndexA);
	AddSwitchEvent(kTimeB, kPidB, 0, 0, kCommIndexA);

	context_.package_uid = kUidA;

	auto packet_buffer = packet_.SerializeAsString();

	RedactSchedSwitchHarness redact;
	redact.emplace_transform<ClearComms>();

	ASSERT_OK(redact.Transform(context_, &packet_buffer));

	protos::gen::TracePacket packet;
	ASSERT_TRUE(packet.ParseFromString(packet_buffer));

	const auto& bundle = packet.ftrace_events();
	ASSERT_TRUE(bundle.has_compact_sched());

	const auto& compact_sched = bundle.compact_sched();

	// A new entry should have been appended, but comm A (previously shared)
	// should still exist in the table.
	ASSERT_EQ(compact_sched.intern_table_size(), 3);
	ASSERT_EQ(compact_sched.intern_table().front(), kCommA);
	ASSERT_EQ(compact_sched.intern_table().back(), kCommNone);
	}

	TEST_F(RedactCompactSchedSwitchTest, RemovesAllCommsIfPackageDoesntExist) {
	uint32_t kCommIndexA = 0;
	uint32_t kCommIndexB = 1;

	// The new entry will be appended to the table. Another primitive can be used
	// to reduce the intern string table.
	uint32_t kCommIndexNone = 2;

	AddSwitchEvent(kTimeA, kPidA, 0, 0, kCommIndexA);
	AddSwitchEvent(kTimeB, kPidB, 0, 0, kCommIndexB);

	context_.package_uid = kUidC;

	auto packet_buffer = packet_.SerializeAsString();

	RedactSchedSwitchHarness redact;
	redact.emplace_transform<ClearComms>();

	ASSERT_OK(redact.Transform(context_, &packet_buffer));

	protos::gen::TracePacket packet;
	ASSERT_TRUE(packet.ParseFromString(packet_buffer));

	const auto& bundle = packet.ftrace_events();
	ASSERT_TRUE(bundle.has_compact_sched());

	const auto& compact_sched = bundle.compact_sched();

	// A new entry (empty string) should have been added to the table.
	ASSERT_EQ(compact_sched.intern_table_size(), 3);
	ASSERT_EQ(compact_sched.intern_table().back(), kCommNone);

	ASSERT_EQ(compact_sched.switch_next_comm_index_size(), 2);
	ASSERT_EQ(compact_sched.switch_next_comm_index().at(0), kCommIndexNone);
	ASSERT_EQ(compact_sched.switch_next_comm_index().at(1), kCommIndexNone);
	}

	TEST_F(RedactCompactSchedSwitchTest, CanChangePid) {
	uint32_t kCommIndexA = 0;
	uint32_t kCommIndexB = 1;

	AddSwitchEvent(kTimeA, kPidA, 0, 0, kCommIndexA);
	AddSwitchEvent(kTimeB, kPidB, 0, 0, kCommIndexB);

	context_.package_uid = kUidA; // This value is not needed to use NegatePid.

	auto packet_buffer = packet_.SerializeAsString();

	RedactSchedSwitchHarness redact;
	redact.emplace_transform<NegatePid>();

	ASSERT_OK(redact.Transform(context_, &packet_buffer));

	protos::gen::TracePacket packet;
	ASSERT_TRUE(packet.ParseFromString(packet_buffer));

	const auto& bundle = packet.ftrace_events();
	ASSERT_TRUE(bundle.has_compact_sched());

	const auto& compact_sched = bundle.compact_sched();

	// The intern table should not change.
	ASSERT_EQ(compact_sched.intern_table_size(), 2);

	ASSERT_EQ(compact_sched.switch_next_pid_size(), 2);
	ASSERT_EQ(compact_sched.switch_next_pid().at(0), -kPidA);
	ASSERT_EQ(compact_sched.switch_next_pid().at(1), -kPidB);
	}

	} // namespace perfetto::trace_redaction