update_engine/update_manager/evaluation_context_unittest.cc - nest-cam/4320010/update_engine - Git at Google

 //
 // Copyright (C) 2014 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 "update_engine/update_manager/evaluation_context.h"

 #include <memory>
 #include <string>

 #include <base/bind.h>
 #include <brillo/message_loops/fake_message_loop.h>
 #include <brillo/message_loops/message_loop_utils.h>
 #include <gtest/gtest.h>

 #include "update_engine/common/fake_clock.h"
 #include "update_engine/update_manager/fake_variable.h"
 #include "update_engine/update_manager/generic_variables.h"
 #include "update_engine/update_manager/mock_variable.h"
 #include "update_engine/update_manager/umtest_utils.h"

 using base::Bind;
 using base::Closure;
 using base::Time;
 using base::TimeDelta;
 using brillo::MessageLoop;
 using brillo::MessageLoopRunMaxIterations;
 using brillo::MessageLoopRunUntil;
 using chromeos_update_engine::FakeClock;
 using std::string;
 using std::unique_ptr;
 using testing::Return;
 using testing::StrictMock;
 using testing::_;

 namespace chromeos_update_manager {

 namespace {

 void DoNothing() {}

 // Sets the value of the passed pointer to true.
 void SetTrue(bool* value) {
   *value = true;
 }

 bool GetBoolean(bool* value) {
   return *value;
 }

 template<typename T>
 void ReadVar(scoped_refptr<EvaluationContext> ec, Variable<T>* var) {
   ec->GetValue(var);
 }

 // Runs |evaluation|; if the value pointed by |count_p| is greater than zero,
 // decrement it and schedule a reevaluation; otherwise, writes true to |done_p|.
 void EvaluateRepeatedly(Closure evaluation, scoped_refptr<EvaluationContext> ec,
                         int* count_p, bool* done_p) {
   evaluation.Run();

   // Schedule reevaluation if needed.
   if (*count_p > 0) {
     Closure closure = Bind(EvaluateRepeatedly, evaluation, ec, count_p, done_p);
     ASSERT_TRUE(ec->RunOnValueChangeOrTimeout(closure))
         << "Failed to schedule reevaluation, count_p=" << *count_p;
     (*count_p)--;
   } else {
     *done_p = true;
   }
 }

 }  // namespace

 class UmEvaluationContextTest : public ::testing::Test {
  protected:
   void SetUp() override {
     loop_.SetAsCurrent();
     // Apr 22, 2009 19:25:00 UTC (this is a random reference point).
     fake_clock_.SetMonotonicTime(Time::FromTimeT(1240428300));
     // Mar 2, 2006 1:23:45 UTC.
     fake_clock_.SetWallclockTime(Time::FromTimeT(1141262625));
     eval_ctx_ = new EvaluationContext(
         &fake_clock_, default_timeout_, default_timeout_,
         unique_ptr<base::Callback<void(EvaluationContext*)>>(nullptr));
   }

   void TearDown() override {
     // Ensure that the evaluation context did not leak and is actually being
     // destroyed.
     if (eval_ctx_) {
       base::WeakPtr<EvaluationContext> eval_ctx_weak_alias =
           eval_ctx_->weak_ptr_factory_.GetWeakPtr();
       ASSERT_NE(nullptr, eval_ctx_weak_alias.get());
       eval_ctx_ = nullptr;
       EXPECT_EQ(nullptr, eval_ctx_weak_alias.get())
           << "The evaluation context was not destroyed! This is likely a bug "
              "in how the test was written, look for leaking handles to the EC, "
              "possibly through closure objects.";
     }

     // Check that the evaluation context removed all the observers.
     EXPECT_TRUE(fake_int_var_.observer_list_.empty());
     EXPECT_TRUE(fake_async_var_.observer_list_.empty());
     EXPECT_TRUE(fake_const_var_.observer_list_.empty());
     EXPECT_TRUE(fake_poll_var_.observer_list_.empty());

     EXPECT_FALSE(loop_.PendingTasks());
   }

   TimeDelta default_timeout_ = TimeDelta::FromSeconds(5);

   brillo::FakeMessageLoop loop_{nullptr};
   FakeClock fake_clock_;
   scoped_refptr<EvaluationContext> eval_ctx_;

   // FakeVariables used for testing the EvaluationContext. These are required
   // here to prevent them from going away *before* the EvaluationContext under
   // test does, which keeps a reference to them.
   FakeVariable<bool> fail_var_ = {"fail_var", kVariableModePoll};
   FakeVariable<int> fake_int_var_ = {"fake_int", kVariableModePoll};
   FakeVariable<string> fake_async_var_ = {"fake_async", kVariableModeAsync};
   FakeVariable<string> fake_const_var_ = {"fake_const", kVariableModeConst};
   FakeVariable<string> fake_poll_var_ = {"fake_poll",
                                          TimeDelta::FromSeconds(1)};
   StrictMock<MockVariable<string>> mock_var_async_ {
     "mock_var_async", kVariableModeAsync};
   StrictMock<MockVariable<string>> mock_var_poll_ {
     "mock_var_poll", kVariableModePoll};
 };

 TEST_F(UmEvaluationContextTest, GetValueFails) {
   // FakeVariable is initialized as returning null.
   EXPECT_EQ(nullptr, eval_ctx_->GetValue(&fake_int_var_));
 }

 TEST_F(UmEvaluationContextTest, GetValueFailsWithInvalidVar) {
   EXPECT_EQ(nullptr, eval_ctx_->GetValue(static_cast<Variable<int>*>(nullptr)));
 }

 TEST_F(UmEvaluationContextTest, GetValueReturns) {
   const int* p_fake_int;

   fake_int_var_.reset(new int(42));
   p_fake_int = eval_ctx_->GetValue(&fake_int_var_);
   ASSERT_NE(nullptr, p_fake_int);
   EXPECT_EQ(42, *p_fake_int);
 }

 TEST_F(UmEvaluationContextTest, GetValueCached) {
   const int* p_fake_int;

   fake_int_var_.reset(new int(42));
   p_fake_int = eval_ctx_->GetValue(&fake_int_var_);

   // Check that if the variable changes, the EvaluationContext keeps returning
   // the cached value.
   fake_int_var_.reset(new int(5));

   p_fake_int = eval_ctx_->GetValue(&fake_int_var_);
   ASSERT_NE(nullptr, p_fake_int);
   EXPECT_EQ(42, *p_fake_int);
 }

 TEST_F(UmEvaluationContextTest, GetValueCachesNull) {
   const int* p_fake_int = eval_ctx_->GetValue(&fake_int_var_);
   EXPECT_EQ(nullptr, p_fake_int);

   fake_int_var_.reset(new int(42));
   // A second attempt to read the variable should not work because this
   // EvaluationContext already got a null value.
   p_fake_int = eval_ctx_->GetValue(&fake_int_var_);
   EXPECT_EQ(nullptr, p_fake_int);
 }

 TEST_F(UmEvaluationContextTest, GetValueMixedTypes) {
   const int* p_fake_int;
   const string* p_fake_string;

   fake_int_var_.reset(new int(42));
   fake_poll_var_.reset(new string("Hello world!"));
   // Check that the EvaluationContext can handle multiple Variable types. This
   // is mostly a compile-time check due to the template nature of this method.
   p_fake_int = eval_ctx_->GetValue(&fake_int_var_);
   p_fake_string = eval_ctx_->GetValue(&fake_poll_var_);

   ASSERT_NE(nullptr, p_fake_int);
   EXPECT_EQ(42, *p_fake_int);

   ASSERT_NE(nullptr, p_fake_string);
   EXPECT_EQ("Hello world!", *p_fake_string);
 }

 // Test that we don't schedule an event if there's no variable to wait for.
 TEST_F(UmEvaluationContextTest, RunOnValueChangeOrTimeoutWithoutVariables) {
   fake_const_var_.reset(new string("Hello world!"));
   EXPECT_EQ(*eval_ctx_->GetValue(&fake_const_var_), "Hello world!");

   EXPECT_FALSE(eval_ctx_->RunOnValueChangeOrTimeout(Bind(&DoNothing)));
 }

 // Test that reevaluation occurs when an async variable it depends on changes.
 TEST_F(UmEvaluationContextTest, RunOnValueChangeOrTimeoutWithVariables) {
   fake_async_var_.reset(new string("Async value"));
   eval_ctx_->GetValue(&fake_async_var_);

   bool value = false;
   EXPECT_TRUE(eval_ctx_->RunOnValueChangeOrTimeout(Bind(&SetTrue, &value)));
   // Check that the scheduled callback isn't run until we signal a ValueChaged.
   MessageLoopRunMaxIterations(MessageLoop::current(), 100);
   EXPECT_FALSE(value);

   fake_async_var_.NotifyValueChanged();
   EXPECT_FALSE(value);
   // Ensure that the scheduled callback isn't run until we are back on the main
   // loop.
   MessageLoopRunMaxIterations(MessageLoop::current(), 100);
   EXPECT_TRUE(value);
 }

 // Test that we don't re-schedule the events if we are attending one.
 TEST_F(UmEvaluationContextTest, RunOnValueChangeOrTimeoutCalledTwice) {
   fake_async_var_.reset(new string("Async value"));
   eval_ctx_->GetValue(&fake_async_var_);

   bool value = false;
   EXPECT_TRUE(eval_ctx_->RunOnValueChangeOrTimeout(Bind(&SetTrue, &value)));
   EXPECT_FALSE(eval_ctx_->RunOnValueChangeOrTimeout(Bind(&SetTrue, &value)));

   // The scheduled event should still work.
   fake_async_var_.NotifyValueChanged();
   MessageLoopRunMaxIterations(MessageLoop::current(), 100);
   EXPECT_TRUE(value);
 }

 // Test that reevaluation occurs when a polling timeout fires.
 TEST_F(UmEvaluationContextTest, RunOnValueChangeOrTimeoutRunsFromTimeout) {
   fake_poll_var_.reset(new string("Polled value"));
   eval_ctx_->GetValue(&fake_poll_var_);

   bool value = false;
   EXPECT_TRUE(eval_ctx_->RunOnValueChangeOrTimeout(Bind(&SetTrue, &value)));
   // Check that the scheduled callback isn't run until the timeout occurs.
   MessageLoopRunMaxIterations(MessageLoop::current(), 10);
   EXPECT_FALSE(value);
   MessageLoopRunUntil(MessageLoop::current(),
                       TimeDelta::FromSeconds(10),
                       Bind(&GetBoolean, &value));
   EXPECT_TRUE(value);
 }

 // Test that callback is called when evaluation context expires, and that it
 // cannot be used again unless the expiration deadline is reset.
 TEST_F(UmEvaluationContextTest, RunOnValueChangeOrTimeoutExpires) {
   fake_async_var_.reset(new string("Async value"));
   eval_ctx_->GetValue(&fake_async_var_);

   bool value = false;
   EXPECT_TRUE(eval_ctx_->RunOnValueChangeOrTimeout(Bind(&SetTrue, &value)));
   // Check that the scheduled callback isn't run until the timeout occurs.
   MessageLoopRunMaxIterations(MessageLoop::current(), 10);
   EXPECT_FALSE(value);
   MessageLoopRunUntil(MessageLoop::current(),
                       TimeDelta::FromSeconds(10),
                       Bind(&GetBoolean, &value));
   EXPECT_TRUE(value);

   // Ensure that we cannot reschedule an evaluation.
   EXPECT_FALSE(eval_ctx_->RunOnValueChangeOrTimeout(Bind(&DoNothing)));

   // Ensure that we can reschedule an evaluation after resetting expiration.
   eval_ctx_->ResetExpiration();
   EXPECT_TRUE(eval_ctx_->RunOnValueChangeOrTimeout(Bind(&DoNothing)));
 }

 // Test that we clear the events when destroying the EvaluationContext.
 TEST_F(UmEvaluationContextTest, RemoveObserversAndTimeoutTest) {
   fake_async_var_.reset(new string("Async value"));
   eval_ctx_->GetValue(&fake_async_var_);

   bool value = false;
   EXPECT_TRUE(eval_ctx_->RunOnValueChangeOrTimeout(Bind(&SetTrue, &value)));
   eval_ctx_ = nullptr;

   // This should not trigger the callback since the EvaluationContext waiting
   // for it is gone, and it should have remove all its observers.
   fake_async_var_.NotifyValueChanged();
   MessageLoopRunMaxIterations(MessageLoop::current(), 100);
   EXPECT_FALSE(value);
 }

 // Scheduling two reevaluations from the callback should succeed.
 TEST_F(UmEvaluationContextTest,
        RunOnValueChangeOrTimeoutReevaluatesRepeatedly) {
   fake_poll_var_.reset(new string("Polled value"));
   Closure evaluation = Bind(ReadVar<string>, eval_ctx_, &fake_poll_var_);
   int num_reevaluations = 2;
   bool done = false;

   // Run the evaluation once.
   evaluation.Run();

   // Schedule repeated reevaluations.
   Closure closure = Bind(EvaluateRepeatedly, evaluation, eval_ctx_,
                          &num_reevaluations, &done);
   ASSERT_TRUE(eval_ctx_->RunOnValueChangeOrTimeout(closure));
   MessageLoopRunUntil(MessageLoop::current(),
                       TimeDelta::FromSeconds(10),
                       Bind(&GetBoolean, &done));
   EXPECT_EQ(0, num_reevaluations);
 }

 // Test that we can delete the EvaluationContext while having pending events.
 TEST_F(UmEvaluationContextTest, ObjectDeletedWithPendingEventsTest) {
   fake_async_var_.reset(new string("Async value"));
   fake_poll_var_.reset(new string("Polled value"));
   eval_ctx_->GetValue(&fake_async_var_);
   eval_ctx_->GetValue(&fake_poll_var_);
   EXPECT_TRUE(eval_ctx_->RunOnValueChangeOrTimeout(Bind(&DoNothing)));
   // TearDown() checks for leaked observers on this async_variable, which means
   // that our object is still alive after removing its reference.
 }

 // Test that timed events fired after removal of the EvaluationContext don't
 // crash.
 TEST_F(UmEvaluationContextTest, TimeoutEventAfterDeleteTest) {
   FakeVariable<string> fake_short_poll_var = {"fake_short_poll",
                                               TimeDelta::FromSeconds(1)};
   fake_short_poll_var.reset(new string("Polled value"));
   eval_ctx_->GetValue(&fake_short_poll_var);
   bool value = false;
   EXPECT_TRUE(eval_ctx_->RunOnValueChangeOrTimeout(Bind(&SetTrue, &value)));
   // Remove the last reference to the EvaluationContext and run the loop for
   // 10 seconds to give time to the main loop to trigger the timeout Event (of 1
   // second). Our callback should not be called because the EvaluationContext
   // was removed before the timeout event is attended.
   eval_ctx_ = nullptr;
   MessageLoopRunUntil(MessageLoop::current(),
                       TimeDelta::FromSeconds(10),
                       Bind(&GetBoolean, &value));
   EXPECT_FALSE(value);
 }

 TEST_F(UmEvaluationContextTest, DefaultTimeout) {
   // Test that the evaluation timeout calculation uses the default timeout on
   // setup.
   EXPECT_CALL(mock_var_async_, GetValue(default_timeout_, _))
       .WillOnce(Return(nullptr));
   EXPECT_EQ(nullptr, eval_ctx_->GetValue(&mock_var_async_));
 }

 TEST_F(UmEvaluationContextTest, TimeoutUpdatesWithMonotonicTime) {
   fake_clock_.SetMonotonicTime(
       fake_clock_.GetMonotonicTime() + TimeDelta::FromSeconds(1));

   TimeDelta timeout = default_timeout_ - TimeDelta::FromSeconds(1);

   EXPECT_CALL(mock_var_async_, GetValue(timeout, _))
       .WillOnce(Return(nullptr));
   EXPECT_EQ(nullptr, eval_ctx_->GetValue(&mock_var_async_));
 }

 TEST_F(UmEvaluationContextTest, ResetEvaluationResetsTimesWallclock) {
   Time cur_time = fake_clock_.GetWallclockTime();
   // Advance the time on the clock but don't call ResetEvaluation yet.
   fake_clock_.SetWallclockTime(cur_time + TimeDelta::FromSeconds(4));

   EXPECT_TRUE(eval_ctx_->IsWallclockTimeGreaterThan(
           cur_time - TimeDelta::FromSeconds(1)));
   EXPECT_FALSE(eval_ctx_->IsWallclockTimeGreaterThan(cur_time));
   EXPECT_FALSE(eval_ctx_->IsWallclockTimeGreaterThan(
           cur_time + TimeDelta::FromSeconds(1)));
   // Call ResetEvaluation now, which should use the new evaluation time.
   eval_ctx_->ResetEvaluation();

   cur_time = fake_clock_.GetWallclockTime();
   EXPECT_TRUE(eval_ctx_->IsWallclockTimeGreaterThan(
           cur_time - TimeDelta::FromSeconds(1)));
   EXPECT_FALSE(eval_ctx_->IsWallclockTimeGreaterThan(cur_time));
   EXPECT_FALSE(eval_ctx_->IsWallclockTimeGreaterThan(
           cur_time + TimeDelta::FromSeconds(1)));
 }

 TEST_F(UmEvaluationContextTest, ResetEvaluationResetsTimesMonotonic) {
   Time cur_time = fake_clock_.GetMonotonicTime();
   // Advance the time on the clock but don't call ResetEvaluation yet.
   fake_clock_.SetMonotonicTime(cur_time + TimeDelta::FromSeconds(4));

   EXPECT_TRUE(eval_ctx_->IsMonotonicTimeGreaterThan(
           cur_time - TimeDelta::FromSeconds(1)));
   EXPECT_FALSE(eval_ctx_->IsMonotonicTimeGreaterThan(cur_time));
   EXPECT_FALSE(eval_ctx_->IsMonotonicTimeGreaterThan(
           cur_time + TimeDelta::FromSeconds(1)));
   // Call ResetEvaluation now, which should use the new evaluation time.
   eval_ctx_->ResetEvaluation();

   cur_time = fake_clock_.GetMonotonicTime();
   EXPECT_TRUE(eval_ctx_->IsMonotonicTimeGreaterThan(
           cur_time - TimeDelta::FromSeconds(1)));
   EXPECT_FALSE(eval_ctx_->IsMonotonicTimeGreaterThan(cur_time));
   EXPECT_FALSE(eval_ctx_->IsMonotonicTimeGreaterThan(
           cur_time + TimeDelta::FromSeconds(1)));
 }

 TEST_F(UmEvaluationContextTest,
        IsWallclockTimeGreaterThanSignalsTriggerReevaluation) {
   EXPECT_FALSE(eval_ctx_->IsWallclockTimeGreaterThan(
       fake_clock_.GetWallclockTime() + TimeDelta::FromSeconds(1)));

   // The "false" from IsWallclockTimeGreaterThan means that's not that timestamp
   // yet, so this should schedule a callback for when that happens.
   EXPECT_TRUE(eval_ctx_->RunOnValueChangeOrTimeout(Bind(&DoNothing)));
 }

 TEST_F(UmEvaluationContextTest,
        IsMonotonicTimeGreaterThanSignalsTriggerReevaluation) {
   EXPECT_FALSE(eval_ctx_->IsMonotonicTimeGreaterThan(
       fake_clock_.GetMonotonicTime() + TimeDelta::FromSeconds(1)));

   // The "false" from IsMonotonicTimeGreaterThan means that's not that timestamp
   // yet, so this should schedule a callback for when that happens.
   EXPECT_TRUE(eval_ctx_->RunOnValueChangeOrTimeout(Bind(&DoNothing)));
 }

 TEST_F(UmEvaluationContextTest,
        IsWallclockTimeGreaterThanDoesntRecordPastTimestamps) {
   // IsWallclockTimeGreaterThan() should ignore timestamps on the past for
   // reevaluation.
   EXPECT_TRUE(eval_ctx_->IsWallclockTimeGreaterThan(
       fake_clock_.GetWallclockTime() - TimeDelta::FromSeconds(20)));
   EXPECT_TRUE(eval_ctx_->IsWallclockTimeGreaterThan(
       fake_clock_.GetWallclockTime() - TimeDelta::FromSeconds(1)));

   // Callback should not be scheduled.
   EXPECT_FALSE(eval_ctx_->RunOnValueChangeOrTimeout(Bind(&DoNothing)));
 }

 TEST_F(UmEvaluationContextTest,
        IsMonotonicTimeGreaterThanDoesntRecordPastTimestamps) {
   // IsMonotonicTimeGreaterThan() should ignore timestamps on the past for
   // reevaluation.
   EXPECT_TRUE(eval_ctx_->IsMonotonicTimeGreaterThan(
       fake_clock_.GetMonotonicTime() - TimeDelta::FromSeconds(20)));
   EXPECT_TRUE(eval_ctx_->IsMonotonicTimeGreaterThan(
       fake_clock_.GetMonotonicTime() - TimeDelta::FromSeconds(1)));

   // Callback should not be scheduled.
   EXPECT_FALSE(eval_ctx_->RunOnValueChangeOrTimeout(Bind(&DoNothing)));
 }

 TEST_F(UmEvaluationContextTest, DumpContext) {
   // |fail_var_| yield "(no value)" since it is unset.
   eval_ctx_->GetValue(&fail_var_);

   // Check that this is included.
   fake_int_var_.reset(new int(42));
   eval_ctx_->GetValue(&fake_int_var_);

   // Check that double-quotes are escaped properly.
   fake_poll_var_.reset(new string("Hello \"world\"!"));
   eval_ctx_->GetValue(&fake_poll_var_);

   // Note that the variables are printed in alphabetical order. Also
   // see UmEvaluationContextText::SetUp() where the values used for
   // |evaluation_start_{monotonic,wallclock| are set.
   EXPECT_EQ("{\n"
             "   \"evaluation_start_monotonic\": \"4/22/2009 19:25:00 GMT\",\n"
             "   \"evaluation_start_wallclock\": \"3/2/2006 1:23:45 GMT\",\n"
             "   \"variables\": {\n"
             "      \"fail_var\": \"(no value)\",\n"
             "      \"fake_int\": \"42\",\n"
             "      \"fake_poll\": \"Hello \\\"world\\\"!\"\n"
             "   }\n"
             "}",
             eval_ctx_->DumpContext());
 }

 }  // namespace chromeos_update_manager
	//
	// Copyright (C) 2014 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 "update_engine/update_manager/evaluation_context.h"

	#include <memory>
	#include <string>

	#include <base/bind.h>
	#include <brillo/message_loops/fake_message_loop.h>
	#include <brillo/message_loops/message_loop_utils.h>
	#include <gtest/gtest.h>

	#include "update_engine/common/fake_clock.h"
	#include "update_engine/update_manager/fake_variable.h"
	#include "update_engine/update_manager/generic_variables.h"
	#include "update_engine/update_manager/mock_variable.h"
	#include "update_engine/update_manager/umtest_utils.h"

	using base::Bind;
	using base::Closure;
	using base::Time;
	using base::TimeDelta;
	using brillo::MessageLoop;
	using brillo::MessageLoopRunMaxIterations;
	using brillo::MessageLoopRunUntil;
	using chromeos_update_engine::FakeClock;
	using std::string;
	using std::unique_ptr;
	using testing::Return;
	using testing::StrictMock;
	using testing::_;

	namespace chromeos_update_manager {

	namespace {

	void DoNothing() {}

	// Sets the value of the passed pointer to true.
	void SetTrue(bool* value) {
	*value = true;
	}

	bool GetBoolean(bool* value) {
	return *value;
	}

	template<typename T>
	void ReadVar(scoped_refptr<EvaluationContext> ec, Variable<T>* var) {
	ec->GetValue(var);
	}

	// Runs \|evaluation\|; if the value pointed by \|count_p\| is greater than zero,
	// decrement it and schedule a reevaluation; otherwise, writes true to \|done_p\|.
	void EvaluateRepeatedly(Closure evaluation, scoped_refptr<EvaluationContext> ec,
	int* count_p, bool* done_p) {
	evaluation.Run();

	// Schedule reevaluation if needed.
	if (*count_p > 0) {
	Closure closure = Bind(EvaluateRepeatedly, evaluation, ec, count_p, done_p);
	ASSERT_TRUE(ec->RunOnValueChangeOrTimeout(closure))
	<< "Failed to schedule reevaluation, count_p=" << *count_p;
	(*count_p)--;
	} else {
	*done_p = true;
	}
	}

	} // namespace

	class UmEvaluationContextTest : public ::testing::Test {
	protected:
	void SetUp() override {
	loop_.SetAsCurrent();
	// Apr 22, 2009 19:25:00 UTC (this is a random reference point).
	fake_clock_.SetMonotonicTime(Time::FromTimeT(1240428300));
	// Mar 2, 2006 1:23:45 UTC.
	fake_clock_.SetWallclockTime(Time::FromTimeT(1141262625));
	eval_ctx_ = new EvaluationContext(
	&fake_clock_, default_timeout_, default_timeout_,
	unique_ptr<base::Callback<void(EvaluationContext*)>>(nullptr));
	}

	void TearDown() override {
	// Ensure that the evaluation context did not leak and is actually being
	// destroyed.
	if (eval_ctx_) {
	base::WeakPtr<EvaluationContext> eval_ctx_weak_alias =
	eval_ctx_->weak_ptr_factory_.GetWeakPtr();
	ASSERT_NE(nullptr, eval_ctx_weak_alias.get());
	eval_ctx_ = nullptr;
	EXPECT_EQ(nullptr, eval_ctx_weak_alias.get())
	<< "The evaluation context was not destroyed! This is likely a bug "
	"in how the test was written, look for leaking handles to the EC, "
	"possibly through closure objects.";
	}

	// Check that the evaluation context removed all the observers.
	EXPECT_TRUE(fake_int_var_.observer_list_.empty());
	EXPECT_TRUE(fake_async_var_.observer_list_.empty());
	EXPECT_TRUE(fake_const_var_.observer_list_.empty());
	EXPECT_TRUE(fake_poll_var_.observer_list_.empty());

	EXPECT_FALSE(loop_.PendingTasks());
	}

	TimeDelta default_timeout_ = TimeDelta::FromSeconds(5);

	brillo::FakeMessageLoop loop_{nullptr};
	FakeClock fake_clock_;
	scoped_refptr<EvaluationContext> eval_ctx_;

	// FakeVariables used for testing the EvaluationContext. These are required
	// here to prevent them from going away before the EvaluationContext under
	// test does, which keeps a reference to them.
	FakeVariable<bool> fail_var_ = {"fail_var", kVariableModePoll};
	FakeVariable<int> fake_int_var_ = {"fake_int", kVariableModePoll};
	FakeVariable<string> fake_async_var_ = {"fake_async", kVariableModeAsync};
	FakeVariable<string> fake_const_var_ = {"fake_const", kVariableModeConst};
	FakeVariable<string> fake_poll_var_ = {"fake_poll",
	TimeDelta::FromSeconds(1)};
	StrictMock<MockVariable<string>> mock_var_async_ {
	"mock_var_async", kVariableModeAsync};
	StrictMock<MockVariable<string>> mock_var_poll_ {
	"mock_var_poll", kVariableModePoll};
	};

	TEST_F(UmEvaluationContextTest, GetValueFails) {
	// FakeVariable is initialized as returning null.
	EXPECT_EQ(nullptr, eval_ctx_->GetValue(&fake_int_var_));
	}

	TEST_F(UmEvaluationContextTest, GetValueFailsWithInvalidVar) {
	EXPECT_EQ(nullptr, eval_ctx_->GetValue(static_cast<Variable<int>*>(nullptr)));
	}

	TEST_F(UmEvaluationContextTest, GetValueReturns) {
	const int* p_fake_int;

	fake_int_var_.reset(new int(42));
	p_fake_int = eval_ctx_->GetValue(&fake_int_var_);
	ASSERT_NE(nullptr, p_fake_int);
	EXPECT_EQ(42, *p_fake_int);
	}

	TEST_F(UmEvaluationContextTest, GetValueCached) {
	const int* p_fake_int;

	fake_int_var_.reset(new int(42));
	p_fake_int = eval_ctx_->GetValue(&fake_int_var_);

	// Check that if the variable changes, the EvaluationContext keeps returning
	// the cached value.
	fake_int_var_.reset(new int(5));

	p_fake_int = eval_ctx_->GetValue(&fake_int_var_);
	ASSERT_NE(nullptr, p_fake_int);
	EXPECT_EQ(42, *p_fake_int);
	}

	TEST_F(UmEvaluationContextTest, GetValueCachesNull) {
	const int* p_fake_int = eval_ctx_->GetValue(&fake_int_var_);
	EXPECT_EQ(nullptr, p_fake_int);

	fake_int_var_.reset(new int(42));
	// A second attempt to read the variable should not work because this
	// EvaluationContext already got a null value.
	p_fake_int = eval_ctx_->GetValue(&fake_int_var_);
	EXPECT_EQ(nullptr, p_fake_int);
	}

	TEST_F(UmEvaluationContextTest, GetValueMixedTypes) {
	const int* p_fake_int;
	const string* p_fake_string;

	fake_int_var_.reset(new int(42));
	fake_poll_var_.reset(new string("Hello world!"));
	// Check that the EvaluationContext can handle multiple Variable types. This
	// is mostly a compile-time check due to the template nature of this method.
	p_fake_int = eval_ctx_->GetValue(&fake_int_var_);
	p_fake_string = eval_ctx_->GetValue(&fake_poll_var_);

	ASSERT_NE(nullptr, p_fake_int);
	EXPECT_EQ(42, *p_fake_int);

	ASSERT_NE(nullptr, p_fake_string);
	EXPECT_EQ("Hello world!", *p_fake_string);
	}

	// Test that we don't schedule an event if there's no variable to wait for.
	TEST_F(UmEvaluationContextTest, RunOnValueChangeOrTimeoutWithoutVariables) {
	fake_const_var_.reset(new string("Hello world!"));
	EXPECT_EQ(*eval_ctx_->GetValue(&fake_const_var_), "Hello world!");

	EXPECT_FALSE(eval_ctx_->RunOnValueChangeOrTimeout(Bind(&DoNothing)));
	}

	// Test that reevaluation occurs when an async variable it depends on changes.
	TEST_F(UmEvaluationContextTest, RunOnValueChangeOrTimeoutWithVariables) {
	fake_async_var_.reset(new string("Async value"));
	eval_ctx_->GetValue(&fake_async_var_);

	bool value = false;
	EXPECT_TRUE(eval_ctx_->RunOnValueChangeOrTimeout(Bind(&SetTrue, &value)));
	// Check that the scheduled callback isn't run until we signal a ValueChaged.
	MessageLoopRunMaxIterations(MessageLoop::current(), 100);
	EXPECT_FALSE(value);

	fake_async_var_.NotifyValueChanged();
	EXPECT_FALSE(value);
	// Ensure that the scheduled callback isn't run until we are back on the main
	// loop.
	MessageLoopRunMaxIterations(MessageLoop::current(), 100);
	EXPECT_TRUE(value);
	}

	// Test that we don't re-schedule the events if we are attending one.
	TEST_F(UmEvaluationContextTest, RunOnValueChangeOrTimeoutCalledTwice) {
	fake_async_var_.reset(new string("Async value"));
	eval_ctx_->GetValue(&fake_async_var_);

	bool value = false;
	EXPECT_TRUE(eval_ctx_->RunOnValueChangeOrTimeout(Bind(&SetTrue, &value)));
	EXPECT_FALSE(eval_ctx_->RunOnValueChangeOrTimeout(Bind(&SetTrue, &value)));

	// The scheduled event should still work.
	fake_async_var_.NotifyValueChanged();
	MessageLoopRunMaxIterations(MessageLoop::current(), 100);
	EXPECT_TRUE(value);
	}

	// Test that reevaluation occurs when a polling timeout fires.
	TEST_F(UmEvaluationContextTest, RunOnValueChangeOrTimeoutRunsFromTimeout) {
	fake_poll_var_.reset(new string("Polled value"));
	eval_ctx_->GetValue(&fake_poll_var_);

	bool value = false;
	EXPECT_TRUE(eval_ctx_->RunOnValueChangeOrTimeout(Bind(&SetTrue, &value)));
	// Check that the scheduled callback isn't run until the timeout occurs.
	MessageLoopRunMaxIterations(MessageLoop::current(), 10);
	EXPECT_FALSE(value);
	MessageLoopRunUntil(MessageLoop::current(),
	TimeDelta::FromSeconds(10),
	Bind(&GetBoolean, &value));
	EXPECT_TRUE(value);
	}

	// Test that callback is called when evaluation context expires, and that it
	// cannot be used again unless the expiration deadline is reset.
	TEST_F(UmEvaluationContextTest, RunOnValueChangeOrTimeoutExpires) {
	fake_async_var_.reset(new string("Async value"));
	eval_ctx_->GetValue(&fake_async_var_);

	bool value = false;
	EXPECT_TRUE(eval_ctx_->RunOnValueChangeOrTimeout(Bind(&SetTrue, &value)));
	// Check that the scheduled callback isn't run until the timeout occurs.
	MessageLoopRunMaxIterations(MessageLoop::current(), 10);
	EXPECT_FALSE(value);
	MessageLoopRunUntil(MessageLoop::current(),
	TimeDelta::FromSeconds(10),
	Bind(&GetBoolean, &value));
	EXPECT_TRUE(value);

	// Ensure that we cannot reschedule an evaluation.
	EXPECT_FALSE(eval_ctx_->RunOnValueChangeOrTimeout(Bind(&DoNothing)));

	// Ensure that we can reschedule an evaluation after resetting expiration.
	eval_ctx_->ResetExpiration();
	EXPECT_TRUE(eval_ctx_->RunOnValueChangeOrTimeout(Bind(&DoNothing)));
	}

	// Test that we clear the events when destroying the EvaluationContext.
	TEST_F(UmEvaluationContextTest, RemoveObserversAndTimeoutTest) {
	fake_async_var_.reset(new string("Async value"));
	eval_ctx_->GetValue(&fake_async_var_);

	bool value = false;
	EXPECT_TRUE(eval_ctx_->RunOnValueChangeOrTimeout(Bind(&SetTrue, &value)));
	eval_ctx_ = nullptr;

	// This should not trigger the callback since the EvaluationContext waiting
	// for it is gone, and it should have remove all its observers.
	fake_async_var_.NotifyValueChanged();
	MessageLoopRunMaxIterations(MessageLoop::current(), 100);
	EXPECT_FALSE(value);
	}

	// Scheduling two reevaluations from the callback should succeed.
	TEST_F(UmEvaluationContextTest,
	RunOnValueChangeOrTimeoutReevaluatesRepeatedly) {
	fake_poll_var_.reset(new string("Polled value"));
	Closure evaluation = Bind(ReadVar<string>, eval_ctx_, &fake_poll_var_);
	int num_reevaluations = 2;
	bool done = false;

	// Run the evaluation once.
	evaluation.Run();

	// Schedule repeated reevaluations.
	Closure closure = Bind(EvaluateRepeatedly, evaluation, eval_ctx_,
	&num_reevaluations, &done);
	ASSERT_TRUE(eval_ctx_->RunOnValueChangeOrTimeout(closure));
	MessageLoopRunUntil(MessageLoop::current(),
	TimeDelta::FromSeconds(10),
	Bind(&GetBoolean, &done));
	EXPECT_EQ(0, num_reevaluations);
	}

	// Test that we can delete the EvaluationContext while having pending events.
	TEST_F(UmEvaluationContextTest, ObjectDeletedWithPendingEventsTest) {
	fake_async_var_.reset(new string("Async value"));
	fake_poll_var_.reset(new string("Polled value"));
	eval_ctx_->GetValue(&fake_async_var_);
	eval_ctx_->GetValue(&fake_poll_var_);
	EXPECT_TRUE(eval_ctx_->RunOnValueChangeOrTimeout(Bind(&DoNothing)));
	// TearDown() checks for leaked observers on this async_variable, which means
	// that our object is still alive after removing its reference.
	}

	// Test that timed events fired after removal of the EvaluationContext don't
	// crash.
	TEST_F(UmEvaluationContextTest, TimeoutEventAfterDeleteTest) {
	FakeVariable<string> fake_short_poll_var = {"fake_short_poll",
	TimeDelta::FromSeconds(1)};
	fake_short_poll_var.reset(new string("Polled value"));
	eval_ctx_->GetValue(&fake_short_poll_var);
	bool value = false;
	EXPECT_TRUE(eval_ctx_->RunOnValueChangeOrTimeout(Bind(&SetTrue, &value)));
	// Remove the last reference to the EvaluationContext and run the loop for
	// 10 seconds to give time to the main loop to trigger the timeout Event (of 1
	// second). Our callback should not be called because the EvaluationContext
	// was removed before the timeout event is attended.
	eval_ctx_ = nullptr;
	MessageLoopRunUntil(MessageLoop::current(),
	TimeDelta::FromSeconds(10),
	Bind(&GetBoolean, &value));
	EXPECT_FALSE(value);
	}

	TEST_F(UmEvaluationContextTest, DefaultTimeout) {
	// Test that the evaluation timeout calculation uses the default timeout on
	// setup.
	EXPECT_CALL(mock_var_async_, GetValue(default_timeout_, _))
	.WillOnce(Return(nullptr));
	EXPECT_EQ(nullptr, eval_ctx_->GetValue(&mock_var_async_));
	}

	TEST_F(UmEvaluationContextTest, TimeoutUpdatesWithMonotonicTime) {
	fake_clock_.SetMonotonicTime(
	fake_clock_.GetMonotonicTime() + TimeDelta::FromSeconds(1));

	TimeDelta timeout = default_timeout_ - TimeDelta::FromSeconds(1);

	EXPECT_CALL(mock_var_async_, GetValue(timeout, _))
	.WillOnce(Return(nullptr));
	EXPECT_EQ(nullptr, eval_ctx_->GetValue(&mock_var_async_));
	}

	TEST_F(UmEvaluationContextTest, ResetEvaluationResetsTimesWallclock) {
	Time cur_time = fake_clock_.GetWallclockTime();
	// Advance the time on the clock but don't call ResetEvaluation yet.
	fake_clock_.SetWallclockTime(cur_time + TimeDelta::FromSeconds(4));

	EXPECT_TRUE(eval_ctx_->IsWallclockTimeGreaterThan(
	cur_time - TimeDelta::FromSeconds(1)));
	EXPECT_FALSE(eval_ctx_->IsWallclockTimeGreaterThan(cur_time));
	EXPECT_FALSE(eval_ctx_->IsWallclockTimeGreaterThan(
	cur_time + TimeDelta::FromSeconds(1)));
	// Call ResetEvaluation now, which should use the new evaluation time.
	eval_ctx_->ResetEvaluation();

	cur_time = fake_clock_.GetWallclockTime();
	EXPECT_TRUE(eval_ctx_->IsWallclockTimeGreaterThan(
	cur_time - TimeDelta::FromSeconds(1)));
	EXPECT_FALSE(eval_ctx_->IsWallclockTimeGreaterThan(cur_time));
	EXPECT_FALSE(eval_ctx_->IsWallclockTimeGreaterThan(
	cur_time + TimeDelta::FromSeconds(1)));
	}

	TEST_F(UmEvaluationContextTest, ResetEvaluationResetsTimesMonotonic) {
	Time cur_time = fake_clock_.GetMonotonicTime();
	// Advance the time on the clock but don't call ResetEvaluation yet.
	fake_clock_.SetMonotonicTime(cur_time + TimeDelta::FromSeconds(4));

	EXPECT_TRUE(eval_ctx_->IsMonotonicTimeGreaterThan(
	cur_time - TimeDelta::FromSeconds(1)));
	EXPECT_FALSE(eval_ctx_->IsMonotonicTimeGreaterThan(cur_time));
	EXPECT_FALSE(eval_ctx_->IsMonotonicTimeGreaterThan(
	cur_time + TimeDelta::FromSeconds(1)));
	// Call ResetEvaluation now, which should use the new evaluation time.
	eval_ctx_->ResetEvaluation();

	cur_time = fake_clock_.GetMonotonicTime();
	EXPECT_TRUE(eval_ctx_->IsMonotonicTimeGreaterThan(
	cur_time - TimeDelta::FromSeconds(1)));
	EXPECT_FALSE(eval_ctx_->IsMonotonicTimeGreaterThan(cur_time));
	EXPECT_FALSE(eval_ctx_->IsMonotonicTimeGreaterThan(
	cur_time + TimeDelta::FromSeconds(1)));
	}

	TEST_F(UmEvaluationContextTest,
	IsWallclockTimeGreaterThanSignalsTriggerReevaluation) {
	EXPECT_FALSE(eval_ctx_->IsWallclockTimeGreaterThan(
	fake_clock_.GetWallclockTime() + TimeDelta::FromSeconds(1)));

	// The "false" from IsWallclockTimeGreaterThan means that's not that timestamp
	// yet, so this should schedule a callback for when that happens.
	EXPECT_TRUE(eval_ctx_->RunOnValueChangeOrTimeout(Bind(&DoNothing)));
	}

	TEST_F(UmEvaluationContextTest,
	IsMonotonicTimeGreaterThanSignalsTriggerReevaluation) {
	EXPECT_FALSE(eval_ctx_->IsMonotonicTimeGreaterThan(
	fake_clock_.GetMonotonicTime() + TimeDelta::FromSeconds(1)));

	// The "false" from IsMonotonicTimeGreaterThan means that's not that timestamp
	// yet, so this should schedule a callback for when that happens.
	EXPECT_TRUE(eval_ctx_->RunOnValueChangeOrTimeout(Bind(&DoNothing)));
	}

	TEST_F(UmEvaluationContextTest,
	IsWallclockTimeGreaterThanDoesntRecordPastTimestamps) {
	// IsWallclockTimeGreaterThan() should ignore timestamps on the past for
	// reevaluation.
	EXPECT_TRUE(eval_ctx_->IsWallclockTimeGreaterThan(
	fake_clock_.GetWallclockTime() - TimeDelta::FromSeconds(20)));
	EXPECT_TRUE(eval_ctx_->IsWallclockTimeGreaterThan(
	fake_clock_.GetWallclockTime() - TimeDelta::FromSeconds(1)));

	// Callback should not be scheduled.
	EXPECT_FALSE(eval_ctx_->RunOnValueChangeOrTimeout(Bind(&DoNothing)));
	}

	TEST_F(UmEvaluationContextTest,
	IsMonotonicTimeGreaterThanDoesntRecordPastTimestamps) {
	// IsMonotonicTimeGreaterThan() should ignore timestamps on the past for
	// reevaluation.
	EXPECT_TRUE(eval_ctx_->IsMonotonicTimeGreaterThan(
	fake_clock_.GetMonotonicTime() - TimeDelta::FromSeconds(20)));
	EXPECT_TRUE(eval_ctx_->IsMonotonicTimeGreaterThan(
	fake_clock_.GetMonotonicTime() - TimeDelta::FromSeconds(1)));

	// Callback should not be scheduled.
	EXPECT_FALSE(eval_ctx_->RunOnValueChangeOrTimeout(Bind(&DoNothing)));
	}

	TEST_F(UmEvaluationContextTest, DumpContext) {
	// \|fail_var_\| yield "(no value)" since it is unset.
	eval_ctx_->GetValue(&fail_var_);

	// Check that this is included.
	fake_int_var_.reset(new int(42));
	eval_ctx_->GetValue(&fake_int_var_);

	// Check that double-quotes are escaped properly.
	fake_poll_var_.reset(new string("Hello \"world\"!"));
	eval_ctx_->GetValue(&fake_poll_var_);

	// Note that the variables are printed in alphabetical order. Also
	// see UmEvaluationContextText::SetUp() where the values used for
	// \|evaluation_start_{monotonic,wallclock\| are set.
	EXPECT_EQ("{\n"
	" \"evaluation_start_monotonic\": \"4/22/2009 19:25:00 GMT\",\n"
	" \"evaluation_start_wallclock\": \"3/2/2006 1:23:45 GMT\",\n"
	" \"variables\": {\n"
	" \"fail_var\": \"(no value)\",\n"
	" \"fake_int\": \"42\",\n"
	" \"fake_poll\": \"Hello \\\"world\\\"!\"\n"
	" }\n"
	"}",
	eval_ctx_->DumpContext());
	}

	} // namespace chromeos_update_manager