text: // Copyright 2017 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 "base/test/test_mock_time_task_runner.h"
  
  #include "base/bind.h"
  #include "base/bind_helpers.h"
  #include "base/cancelable_callback.h"
  #include "base/memory/ref_counted.h"
  #include "base/run_loop.h"
  #include "base/test/bind_test_util.h"
  #include "base/test/gtest_util.h"
  #include "base/test/test_timeouts.h"
  #include "base/threading/sequenced_task_runner_handle.h"
  #include "base/threading/thread.h"
  #include "base/threading/thread_task_runner_handle.h"
  #include "base/time/time.h"
  #include "testing/gtest/include/gtest/gtest.h"
  
  namespace base {
  
  // Basic usage should work the same from default and bound
  // TestMockTimeTaskRunners.
  TEST(TestMockTimeTaskRunnerTest, Basic) {
    static constexpr TestMockTimeTaskRunner::Type kTestCases[] = {
        TestMockTimeTaskRunner::Type::kStandalone,
        TestMockTimeTaskRunner::Type::kBoundToThread};
  
    for (auto type : kTestCases) {
      SCOPED_TRACE(static_cast<int>(type));
  
      auto mock_time_task_runner = MakeRefCounted<TestMockTimeTaskRunner>(type);
      int counter = 0;
  
      mock_time_task_runner->PostTask(
          FROM_HERE, base::BindOnce([](int* counter) { *counter += 1; },
                                    Unretained(&counter)));
      mock_time_task_runner->PostTask(
          FROM_HERE, base::BindOnce([](int* counter) { *counter += 32; },
                                    Unretained(&counter)));
      mock_time_task_runner->PostDelayedTask(
          FROM_HERE,
          base::BindOnce([](int* counter) { *counter += 256; },
                         Unretained(&counter)),
          TimeDelta::FromSeconds(3));
      mock_time_task_runner->PostDelayedTask(
          FROM_HERE,
          base::BindOnce([](int* counter) { *counter += 64; },
                         Unretained(&counter)),
          TimeDelta::FromSeconds(1));
      mock_time_task_runner->PostDelayedTask(
          FROM_HERE,
          base::BindOnce([](int* counter) { *counter += 1024; },
                         Unretained(&counter)),
          TimeDelta::FromMinutes(20));
      mock_time_task_runner->PostDelayedTask(
          FROM_HERE,
          base::BindOnce([](int* counter) { *counter += 4096; },
                         Unretained(&counter)),
          TimeDelta::FromDays(20));
  
      int expected_value = 0;
      EXPECT_EQ(expected_value, counter);
      mock_time_task_runner->RunUntilIdle();
      expected_value += 1;
      expected_value += 32;
      EXPECT_EQ(expected_value, counter);
  
      mock_time_task_runner->RunUntilIdle();
      EXPECT_EQ(expected_value, counter);
  
      mock_time_task_runner->FastForwardBy(TimeDelta::FromSeconds(1));
      expected_value += 64;
      EXPECT_EQ(expected_value, counter);
  
      mock_time_task_runner->FastForwardBy(TimeDelta::FromSeconds(5));
      expected_value += 256;
      EXPECT_EQ(expected_value, counter);
  
      mock_time_task_runner->FastForwardUntilNoTasksRemain();
      expected_value += 1024;
      expected_value += 4096;
      EXPECT_EQ(expected_value, counter);
    }
  }
  
  // A default TestMockTimeTaskRunner shouldn't result in a thread association.
  TEST(TestMockTimeTaskRunnerTest, DefaultUnbound) {
    auto unbound_mock_time_task_runner = MakeRefCounted<TestMockTimeTaskRunner>();
    EXPECT_FALSE(ThreadTaskRunnerHandle::IsSet());
    EXPECT_FALSE(SequencedTaskRunnerHandle::IsSet());
    EXPECT_DEATH_IF_SUPPORTED({ RunLoop().RunUntilIdle(); }, "");
  }
  
  TEST(TestMockTimeTaskRunnerTest, RunLoopDriveableWhenBound) {
    auto bound_mock_time_task_runner = MakeRefCounted<TestMockTimeTaskRunner>(
        TestMockTimeTaskRunner::Type::kBoundToThread);
  
    int counter = 0;
    ThreadTaskRunnerHandle::Get()->PostTask(
        FROM_HERE, base::BindOnce([](int* counter) { *counter += 1; },
                                  Unretained(&counter)));
    ThreadTaskRunnerHandle::Get()->PostTask(
        FROM_HERE, base::BindOnce([](int* counter) { *counter += 32; },
                                  Unretained(&counter)));
    ThreadTaskRunnerHandle::Get()->PostDelayedTask(
        FROM_HERE,
        base::BindOnce([](int* counter) { *counter += 256; },
                       Unretained(&counter)),
        TimeDelta::FromSeconds(3));
    ThreadTaskRunnerHandle::Get()->PostDelayedTask(
        FROM_HERE,
        base::BindOnce([](int* counter) { *counter += 64; },
                       Unretained(&counter)),
        TimeDelta::FromSeconds(1));
    ThreadTaskRunnerHandle::Get()->PostDelayedTask(
        FROM_HERE,
        base::BindOnce([](int* counter) { *counter += 1024; },
                       Unretained(&counter)),
        TimeDelta::FromMinutes(20));
    ThreadTaskRunnerHandle::Get()->PostDelayedTask(
        FROM_HERE,
        base::BindOnce([](int* counter) { *counter += 4096; },
                       Unretained(&counter)),
        TimeDelta::FromDays(20));
  
    int expected_value = 0;
    EXPECT_EQ(expected_value, counter);
    RunLoop().RunUntilIdle();
    expected_value += 1;
    expected_value += 32;
    EXPECT_EQ(expected_value, counter);
  
    RunLoop().RunUntilIdle();
    EXPECT_EQ(expected_value, counter);
  
    {
      RunLoop run_loop;
      ThreadTaskRunnerHandle::Get()->PostDelayedTask(
          FROM_HERE, run_loop.QuitClosure(), TimeDelta::FromSeconds(1));
      ThreadTaskRunnerHandle::Get()->PostDelayedTask(
          FROM_HERE,
          base::BindOnce([](int* counter) { *counter += 8192; },
                         Unretained(&counter)),
          TimeDelta::FromSeconds(1));
  
      // The QuitClosure() should be ordered between the 64 and the 8192
      // increments and should preempt the latter.
      run_loop.Run();
      expected_value += 64;
      EXPECT_EQ(expected_value, counter);
  
      // Running until idle should process the 8192 increment whose delay has
      // expired in the previous Run().
      RunLoop().RunUntilIdle();
      expected_value += 8192;
      EXPECT_EQ(expected_value, counter);
    }
  
    {
      RunLoop run_loop;
      ThreadTaskRunnerHandle::Get()->PostDelayedTask(
          FROM_HERE, run_loop.QuitWhenIdleClosure(), TimeDelta::FromSeconds(5));
      ThreadTaskRunnerHandle::Get()->PostDelayedTask(
          FROM_HERE,
          base::BindOnce([](int* counter) { *counter += 16384; },
                         Unretained(&counter)),
          TimeDelta::FromSeconds(5));
  
      // The QuitWhenIdleClosure() shouldn't preempt equally delayed tasks and as
      // such the 16384 increment should be processed before quitting.
      run_loop.Run();
      expected_value += 256;
      expected_value += 16384;
      EXPECT_EQ(expected_value, counter);
    }
  
    // Process the remaining tasks (note: do not mimic this elsewhere,
    // TestMockTimeTaskRunner::FastForwardUntilNoTasksRemain() is a better API to
    // do this, this is just done here for the purpose of extensively testing the
    // RunLoop approach).
    RunLoop run_loop;
    ThreadTaskRunnerHandle::Get()->PostDelayedTask(
        FROM_HERE, run_loop.QuitWhenIdleClosure(), TimeDelta::FromDays(50));
  
    run_loop.Run();
    expected_value += 1024;
    expected_value += 4096;
    EXPECT_EQ(expected_value, counter);
  }
  
  TEST(TestMockTimeTaskRunnerTest, AvoidCaptureWhenBound) {
    // Make sure that capturing the active task runner --- which sometimes happens
    // unknowingly due to ThreadsafeObserverList deep within some singleton ---
    // does not keep the entire TestMockTimeTaskRunner alive, as in bound mode
    // that's a RunLoop::Delegate, and leaking that renders any further tests that
    // need RunLoop support unrunnable.
    //
    // (This used to happen when code run from ProcessAllTasksNoLaterThan grabbed
    //  the runner.).
    scoped_refptr<SingleThreadTaskRunner> captured;
    {
      auto task_runner = MakeRefCounted<TestMockTimeTaskRunner>(
          TestMockTimeTaskRunner::Type::kBoundToThread);
  
      task_runner->PostTask(FROM_HERE, base::BindLambdaForTesting([&]() {
                              captured = ThreadTaskRunnerHandle::Get();
                            }));
      task_runner->RunUntilIdle();
    }
  
    {
      // This should not complain about RunLoop::Delegate already existing.
      auto task_runner2 = MakeRefCounted<TestMockTimeTaskRunner>(
          TestMockTimeTaskRunner::Type::kBoundToThread);
    }
  }
  
  // Regression test that receiving the quit-when-idle signal when already empty
  // works as intended (i.e. that |TestMockTimeTaskRunner::tasks_lock_cv| is
  // properly signaled).
  TEST(TestMockTimeTaskRunnerTest, RunLoopQuitFromIdle) {
    auto bound_mock_time_task_runner = MakeRefCounted<TestMockTimeTaskRunner>(
        TestMockTimeTaskRunner::Type::kBoundToThread);
  
    Thread quitting_thread("quitting thread");
    quitting_thread.Start();
  
    RunLoop run_loop;
    quitting_thread.task_runner()->PostDelayedTask(
        FROM_HERE, run_loop.QuitWhenIdleClosure(), TestTimeouts::tiny_timeout());
    run_loop.Run();
  }
  
  TEST(TestMockTimeTaskRunnerTest, TakePendingTasks) {
    auto task_runner = MakeRefCounted<TestMockTimeTaskRunner>();
    task_runner->PostTask(FROM_HERE, DoNothing());
    EXPECT_TRUE(task_runner->HasPendingTask());
    EXPECT_EQ(1u, task_runner->TakePendingTasks().size());
    EXPECT_FALSE(task_runner->HasPendingTask());
  }
  
  TEST(TestMockTimeTaskRunnerTest, CancelPendingTask) {
    auto task_runner = MakeRefCounted<TestMockTimeTaskRunner>();
    CancelableOnceClosure task1(DoNothing::Once());
    task_runner->PostDelayedTask(FROM_HERE, task1.callback(),
                                 TimeDelta::FromSeconds(1));
    EXPECT_TRUE(task_runner->HasPendingTask());
    EXPECT_EQ(1u, task_runner->GetPendingTaskCount());
    EXPECT_EQ(TimeDelta::FromSeconds(1), task_runner->NextPendingTaskDelay());
    task1.Cancel();
    EXPECT_FALSE(task_runner->HasPendingTask());
  
    CancelableOnceClosure task2(DoNothing::Once());
    task_runner->PostDelayedTask(FROM_HERE, task2.callback(),
                                 TimeDelta::FromSeconds(1));
    task2.Cancel();
    EXPECT_EQ(0u, task_runner->GetPendingTaskCount());
  
    CancelableOnceClosure task3(DoNothing::Once());
    task_runner->PostDelayedTask(FROM_HERE, task3.callback(),
                                 TimeDelta::FromSeconds(1));
    task3.Cancel();
    EXPECT_EQ(TimeDelta::Max(), task_runner->NextPendingTaskDelay());
  
    CancelableOnceClosure task4(DoNothing::Once());
    task_runner->PostDelayedTask(FROM_HERE, task4.callback(),
                                 TimeDelta::FromSeconds(1));
    task4.Cancel();
    EXPECT_TRUE(task_runner->TakePendingTasks().empty());
  }
  
  TEST(TestMockTimeTaskRunnerTest, NoFastForwardToCancelledTask) {
    auto task_runner = MakeRefCounted<TestMockTimeTaskRunner>();
    TimeTicks start_time = task_runner->NowTicks();
    CancelableOnceClosure task(DoNothing::Once());
    task_runner->PostDelayedTask(FROM_HERE, task.callback(),
                                 TimeDelta::FromSeconds(1));
    EXPECT_EQ(TimeDelta::FromSeconds(1), task_runner->NextPendingTaskDelay());
    task.Cancel();
    task_runner->FastForwardUntilNoTasksRemain();
    EXPECT_EQ(start_time, task_runner->NowTicks());
  }
  
  TEST(TestMockTimeTaskRunnerTest, AdvanceMockTickClockDoesNotRunTasks) {
    auto task_runner = MakeRefCounted<TestMockTimeTaskRunner>();
    TimeTicks start_time = task_runner->NowTicks();
    task_runner->PostTask(FROM_HERE, BindOnce([]() { ADD_FAILURE(); }));
    task_runner->PostDelayedTask(FROM_HERE, BindOnce([]() { ADD_FAILURE(); }),
                                 TimeDelta::FromSeconds(1));
  
    task_runner->AdvanceMockTickClock(TimeDelta::FromSeconds(3));
    EXPECT_EQ(start_time + TimeDelta::FromSeconds(3), task_runner->NowTicks());
    EXPECT_EQ(2u, task_runner->GetPendingTaskCount());
  }
  
  }  // namespace base
  