Add Lazy Creation and Thread Detachment Support in the Scheduler Worker Pool

base/task_scheduler/scheduler_worker_stack_unittest.cc

 // 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.
 
 #include "base/task_scheduler/scheduler_worker_stack.h"
 
 #include "base/logging.h"
 #include "base/memory/ptr_util.h"
 #include "base/memory/ref_counted.h"
 #include "base/task_scheduler/scheduler_worker.h"
@@ skipping 58 matching lines @@
 
  private:
   TaskTracker task_tracker_;
 };
 
 }  // namespace
 
 // Verify that Push() and Pop() add/remove values in FIFO order.
 TEST_F(TaskSchedulerWorkerStackTest, PushPop) {
   SchedulerWorkerStack stack;
+  EXPECT_EQ(nullptr, stack.Pop());
+
   EXPECT_TRUE(stack.IsEmpty());
   EXPECT_EQ(0U, stack.Size());
 
   stack.Push(worker_a_.get());
   EXPECT_FALSE(stack.IsEmpty());
   EXPECT_EQ(1U, stack.Size());
 
   stack.Push(worker_b_.get());
   EXPECT_FALSE(stack.IsEmpty());
   EXPECT_EQ(2U, stack.Size());
@@ skipping 14 matching lines @@
   EXPECT_FALSE(stack.IsEmpty());
   EXPECT_EQ(2U, stack.Size());
 
   EXPECT_EQ(worker_b_.get(), stack.Pop());
   EXPECT_FALSE(stack.IsEmpty());
   EXPECT_EQ(1U, stack.Size());
 
   EXPECT_EQ(worker_a_.get(), stack.Pop());
   EXPECT_TRUE(stack.IsEmpty());
   EXPECT_EQ(0U, stack.Size());
+
+  EXPECT_EQ(nullptr, stack.Pop());
+}
+
+// Verify that Peek() returns the correct values in FIFO order.
+TEST_F(TaskSchedulerWorkerStackTest, PeekPop) {
+  SchedulerWorkerStack stack;
+  EXPECT_EQ(nullptr, stack.Peek());
+
+  EXPECT_TRUE(stack.IsEmpty());
+  EXPECT_EQ(0U, stack.Size());
+
+  stack.Push(worker_a_.get());
+  EXPECT_EQ(worker_a_.get(), stack.Peek());
+  EXPECT_FALSE(stack.IsEmpty());
+  EXPECT_EQ(1U, stack.Size());
+
+  stack.Push(worker_b_.get());
+  EXPECT_EQ(worker_b_.get(), stack.Peek());
+  EXPECT_FALSE(stack.IsEmpty());
+  EXPECT_EQ(2U, stack.Size());
+
+  stack.Push(worker_c_.get());
+  EXPECT_EQ(worker_c_.get(), stack.Peek());
+  EXPECT_FALSE(stack.IsEmpty());
+  EXPECT_EQ(3U, stack.Size());
+
+  EXPECT_EQ(worker_c_.get(), stack.Pop());
+  EXPECT_EQ(worker_b_.get(), stack.Peek());
+  EXPECT_FALSE(stack.IsEmpty());
+  EXPECT_EQ(2U, stack.Size());
+
+  EXPECT_EQ(worker_b_.get(), stack.Pop());
+  EXPECT_EQ(worker_a_.get(), stack.Peek());
+  EXPECT_FALSE(stack.IsEmpty());
+  EXPECT_EQ(1U, stack.Size());
+
+  EXPECT_EQ(worker_a_.get(), stack.Pop());
+  EXPECT_TRUE(stack.IsEmpty());
+  EXPECT_EQ(0U, stack.Size());
+
+  EXPECT_EQ(nullptr, stack.Peek());
+}
+
+// Verify that Contains() returns true for workers on the stack.
+TEST_F(TaskSchedulerWorkerStackTest, Contains) {
+  SchedulerWorkerStack stack;
+  EXPECT_FALSE(stack.Contains(worker_a_.get()));
+  EXPECT_FALSE(stack.Contains(worker_b_.get()));
+  EXPECT_FALSE(stack.Contains(worker_c_.get()));
+
+  stack.Push(worker_a_.get());
+  EXPECT_TRUE(stack.Contains(worker_a_.get()));
+  EXPECT_FALSE(stack.Contains(worker_b_.get()));
+  EXPECT_FALSE(stack.Contains(worker_c_.get()));
+
+  stack.Push(worker_b_.get());
+  EXPECT_TRUE(stack.Contains(worker_a_.get()));
+  EXPECT_TRUE(stack.Contains(worker_b_.get()));
+  EXPECT_FALSE(stack.Contains(worker_c_.get()));
+
+  stack.Push(worker_c_.get());
+  EXPECT_TRUE(stack.Contains(worker_a_.get()));
+  EXPECT_TRUE(stack.Contains(worker_b_.get()));
+  EXPECT_TRUE(stack.Contains(worker_c_.get()));
+
+  stack.Pop();
+  EXPECT_TRUE(stack.Contains(worker_a_.get()));
+  EXPECT_TRUE(stack.Contains(worker_b_.get()));
+  EXPECT_FALSE(stack.Contains(worker_c_.get()));
+
+  stack.Pop();
+  EXPECT_TRUE(stack.Contains(worker_a_.get()));
+  EXPECT_FALSE(stack.Contains(worker_b_.get()));
+  EXPECT_FALSE(stack.Contains(worker_c_.get()));
+
+  stack.Pop();
+  EXPECT_FALSE(stack.Contains(worker_a_.get()));
+  EXPECT_FALSE(stack.Contains(worker_b_.get()));
+  EXPECT_FALSE(stack.Contains(worker_c_.get()));
 }
 
 // Verify that a value can be removed by Remove().
 TEST_F(TaskSchedulerWorkerStackTest, Remove) {
   SchedulerWorkerStack stack;
   EXPECT_TRUE(stack.IsEmpty());
   EXPECT_EQ(0U, stack.Size());
 
   stack.Push(worker_a_.get());
   EXPECT_FALSE(stack.IsEmpty());
@@ skipping 41 matching lines @@
 
 // Verify that Push() DCHECKs when a value is inserted twice.
 TEST_F(TaskSchedulerWorkerStackTest, PushTwice) {
   SchedulerWorkerStack stack;
   stack.Push(worker_a_.get());
   EXPECT_DCHECK_DEATH({ stack.Push(worker_a_.get()); }, "");
 }
 
 }  // namespace internal
 }  // namespace base