[Sync] Refactor ModelSafeWorker::DoWorkAndWaitUntilDone() to avoid code duplication.

components/sync/engine/model_safe_worker_unittest.cc

Index: components/sync/engine/model_safe_worker_unittest.cc
diff --git a/components/sync/engine/model_safe_worker_unittest.cc b/components/sync/engine/model_safe_worker_unittest.cc
index 6340dca2f507f27eeed89db77a133be1e0568974..cb6ceddb970c444f3050db890198830459bb28bb 100644
--- a/components/sync/engine/model_safe_worker_unittest.cc
+++ b/components/sync/engine/model_safe_worker_unittest.cc
@@ -4,13 +4,84 @@
 
 #include "components/sync/engine/model_safe_worker.h"
 
+#include <utility>
+
+#include "base/bind.h"
+#include "base/macros.h"
+#include "base/synchronization/atomic_flag.h"
+#include "base/test/test_simple_task_runner.h"
+#include "base/test/test_timeouts.h"
+#include "base/threading/platform_thread.h"
+#include "base/threading/thread.h"
 #include "base/values.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace syncer {
 namespace {
 
-class ModelSafeWorkerTest : public ::testing::Test {};
+syncer::WorkCallback ClosureToWorkCallback(base::Closure work) {
+  return base::Bind(
+      [](base::Closure work) {
+        work.Run();
+        return syncer::SYNCER_OK;
+      },
+      std::move(work));
+}
+
+class MockModelSafeWorker : public ModelSafeWorker {
+ public:
+  MockModelSafeWorker() = default;
+
+  void ScheduleWork(base::OnceClosure work) override {
+    task_runner_->PostTask(FROM_HERE, std::move(work));
+  }
+
+  ModelSafeGroup GetModelSafeGroup() override { return GROUP_PASSIVE; }
+
+  bool IsOnModelThread() override {
+    return task_runner_->BelongsToCurrentThread();
+  }
+
+  scoped_refptr<base::TestSimpleTaskRunner> task_runner() const {
+    return task_runner_;
+  }
+
+ private:
+  friend class base::RefCountedThreadSafe<MockModelSafeWorker>;
+
+  ~MockModelSafeWorker() override = default;
+
+  const scoped_refptr<base::TestSimpleTaskRunner> task_runner_ =
+      new base::TestSimpleTaskRunner();
+
+  DISALLOW_COPY_AND_ASSIGN(MockModelSafeWorker);
+};
+
+class ModelSafeWorkerTest : public ::testing::Test {
+ protected:
+  ModelSafeWorkerTest() : sync_thread_("SyncThreadForTest") {
+    sync_thread_.Start();
+  }
+
+  void DoWorkAndWaitUntilDoneOnSyncThread(base::Closure work) {
+    sync_thread_.task_runner()->PostTask(
+        FROM_HERE,
+        base::Bind(base::IgnoreResult(&ModelSafeWorker::DoWorkAndWaitUntilDone),
+                   worker_, base::Passed(ClosureToWorkCallback(work))));
+    sync_thread_.task_runner()->PostTask(
+        FROM_HERE, base::Bind(&base::AtomicFlag::Set,
+                              base::Unretained(&sync_thread_unblocked_)));
+  }
+
+  base::AtomicFlag sync_thread_unblocked_;
+  base::Thread sync_thread_;
+  const scoped_refptr<MockModelSafeWorker> worker_ = new MockModelSafeWorker();
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(ModelSafeWorkerTest);
+};
+
+}  // namespace
 
 TEST_F(ModelSafeWorkerTest, ModelSafeRoutingInfoToValue) {
   ModelSafeRoutingInfo routing_info;
@@ -49,5 +120,95 @@ TEST_F(ModelSafeWorkerTest, GetRoutingInfoTypes) {
   EXPECT_EQ(expected_types, GetRoutingInfoTypes(routing_info));
 }
 
-}  // namespace
+TEST_F(ModelSafeWorkerTest, DoWorkAndWaitUntilDone) {
+  bool did_work = false;
+  DoWorkAndWaitUntilDoneOnSyncThread(base::Bind(
+      [](bool* did_work) { *did_work = true; }, base::Unretained(&did_work)));
+
+  EXPECT_FALSE(did_work);
+  EXPECT_FALSE(sync_thread_unblocked_.IsSet());
+
+  // Wait for a task to be posted to |worker_|'s TaskRunner and run it.
+  while (!worker_->task_runner()->HasPendingTask())
+    base::PlatformThread::YieldCurrentThread();
+  worker_->task_runner()->RunUntilIdle();
+
+  EXPECT_TRUE(did_work);
+
+  sync_thread_.Stop();
+  EXPECT_TRUE(sync_thread_unblocked_.IsSet());
+}
+
+TEST_F(ModelSafeWorkerTest, DoWorkAndWaitUntilDoneRequestStopBeforeRunWork) {
+  bool did_work = false;
+  DoWorkAndWaitUntilDoneOnSyncThread(base::Bind(
+      [](bool* did_work) { *did_work = true; }, base::Unretained(&did_work)));
+
+  EXPECT_FALSE(did_work);
+  EXPECT_FALSE(sync_thread_unblocked_.IsSet());
+
+  // Wait for a task to be posted to |worker_|'s TaskRunner.
+  while (!worker_->task_runner()->HasPendingTask())
+    base::PlatformThread::YieldCurrentThread();
+
+  // Stop the worker.
+  worker_->RequestStop();
+
+  // The WorkCallback should not run.
+  worker_->task_runner()->RunUntilIdle();
+  EXPECT_FALSE(did_work);
+
+  sync_thread_.Stop();
+  EXPECT_TRUE(sync_thread_unblocked_.IsSet());
+}
+
+TEST_F(ModelSafeWorkerTest, DoWorkAndWaitUntilDoneDeleteWorkBeforeRun) {
+  bool did_work = false;
+  DoWorkAndWaitUntilDoneOnSyncThread(base::Bind(
+      [](bool* did_work) { *did_work = true; }, base::Unretained(&did_work)));
+
+  EXPECT_FALSE(did_work);
+  EXPECT_FALSE(sync_thread_unblocked_.IsSet());
+
+  // Wait for a task to be posted to |worker_|'s TaskRunner and delete it.
+  while (!worker_->task_runner()->HasPendingTask())
+    base::PlatformThread::YieldCurrentThread();
+  worker_->task_runner()->ClearPendingTasks();
+
+  EXPECT_FALSE(did_work);
+
+  // Deleting the task should have unblocked the sync thread.
+  sync_thread_.Stop();
+  EXPECT_TRUE(sync_thread_unblocked_.IsSet());
+}
+
+TEST_F(ModelSafeWorkerTest, DoWorkAndWaitUntilDoneRequestStopDuringRunWork) {
+  bool did_work = false;
+  DoWorkAndWaitUntilDoneOnSyncThread(base::Bind(
+      [](scoped_refptr<ModelSafeWorker> worker,
+         base::AtomicFlag* sync_thread_unblocked, bool* did_work) {
+        worker->RequestStop();
+        base::PlatformThread::Sleep(TestTimeouts::tiny_timeout());
+
+        // The sync thread should not be unblocked while a WorkCallback is
+        // running.
+        EXPECT_FALSE(sync_thread_unblocked->IsSet());
+
+        *did_work = true;
+      },
+      worker_, base::Unretained(&sync_thread_unblocked_),
+      base::Unretained(&did_work)));
+  EXPECT_FALSE(did_work);
+  EXPECT_FALSE(sync_thread_unblocked_.IsSet());
+
+  // Wait for a task to be posted to |worker_|'s TaskRunner and run it.
+  while (!worker_->task_runner()->HasPendingTask())
+    base::PlatformThread::YieldCurrentThread();
+  worker_->task_runner()->RunUntilIdle();
+
+  EXPECT_TRUE(did_work);
+  sync_thread_.Stop();
+  EXPECT_TRUE(sync_thread_unblocked_.IsSet());
+}
+
 }  // namespace syncer