Add base::TaskTraits::Override().

base/task_scheduler/task_traits_unittest.cc

 // 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/task_scheduler/task_traits.h"
 
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace base {
 
@@ skipping 60 matching lines @@
   constexpr TaskTraits traits_copy(traits);
   EXPECT_EQ(traits.priority_set_explicitly(),
             traits_copy.priority_set_explicitly());
   EXPECT_EQ(traits.priority(), traits_copy.priority());
   EXPECT_EQ(traits.shutdown_behavior(), traits_copy.shutdown_behavior());
   EXPECT_EQ(traits.may_block(), traits_copy.may_block());
   EXPECT_EQ(traits.with_base_sync_primitives(),
             traits_copy.with_base_sync_primitives());
 }
 
+TEST(TaskSchedulerTaskTraitsTest, MergePriority) {

[gab, 2017/05/09 14:32:31]

Rename tests to "Override" too.

[fdoray, 2017/05/09 14:58:33]

Done.

+  constexpr TaskTraits left = {TaskPriority::BACKGROUND};
+  constexpr TaskTraits right = {TaskPriority::USER_BLOCKING};
+  constexpr TaskTraits merged = TaskTraits::Merge(left, right);
+  EXPECT_TRUE(merged.priority_set_explicitly());
+  EXPECT_EQ(TaskPriority::USER_BLOCKING, merged.priority());
+  EXPECT_EQ(TaskShutdownBehavior::SKIP_ON_SHUTDOWN, merged.shutdown_behavior());

[gab, 2017/05/09 14:32:31]

EXPECT_FALSE(shutdown_behavior_set_explitly) also + below

[fdoray, 2017/05/09 14:58:34]

Done.

+  EXPECT_FALSE(merged.may_block());
+  EXPECT_FALSE(merged.with_base_sync_primitives());
+}
+
+TEST(TaskSchedulerTaskTraitsTest, MergeShutdownBehavior) {
+  constexpr TaskTraits left = {TaskShutdownBehavior::CONTINUE_ON_SHUTDOWN};
+  constexpr TaskTraits right = {TaskShutdownBehavior::BLOCK_SHUTDOWN};
+  constexpr TaskTraits merged = TaskTraits::Merge(left, right);
+  EXPECT_FALSE(merged.priority_set_explicitly());
+  EXPECT_EQ(TaskPriority::USER_VISIBLE, merged.priority());
+  EXPECT_EQ(TaskShutdownBehavior::BLOCK_SHUTDOWN, merged.shutdown_behavior());
+  EXPECT_FALSE(merged.may_block());
+  EXPECT_FALSE(merged.with_base_sync_primitives());
+}
+
+TEST(TaskSchedulerTaskTraitsTest, MergeMayBlock) {
+  {
+    constexpr TaskTraits left = {MayBlock()};
+    constexpr TaskTraits right = {};
+    constexpr TaskTraits merged = TaskTraits::Merge(left, right);
+    EXPECT_FALSE(merged.priority_set_explicitly());
+    EXPECT_EQ(TaskPriority::USER_VISIBLE, merged.priority());
+    EXPECT_EQ(TaskShutdownBehavior::SKIP_ON_SHUTDOWN,
+              merged.shutdown_behavior());
+    EXPECT_TRUE(merged.may_block());
+    EXPECT_FALSE(merged.with_base_sync_primitives());
+  }
+  {
+    constexpr TaskTraits left = {};
+    constexpr TaskTraits right = {MayBlock()};
+    constexpr TaskTraits merged = TaskTraits::Merge(left, right);
+    EXPECT_FALSE(merged.priority_set_explicitly());
+    EXPECT_EQ(TaskPriority::USER_VISIBLE, merged.priority());
+    EXPECT_EQ(TaskShutdownBehavior::SKIP_ON_SHUTDOWN,
+              merged.shutdown_behavior());
+    EXPECT_TRUE(merged.may_block());
+    EXPECT_FALSE(merged.with_base_sync_primitives());
+  }
+}
+
+TEST(TaskSchedulerTaskTraitsTest, MergeWithBaseSyncPrimitives) {
+  {
+    constexpr TaskTraits left = {WithBaseSyncPrimitives()};
+    constexpr TaskTraits right = {};
+    constexpr TaskTraits merged = TaskTraits::Merge(left, right);
+    EXPECT_FALSE(merged.priority_set_explicitly());
+    EXPECT_EQ(TaskPriority::USER_VISIBLE, merged.priority());
+    EXPECT_EQ(TaskShutdownBehavior::SKIP_ON_SHUTDOWN,
+              merged.shutdown_behavior());
+    EXPECT_FALSE(merged.may_block());
+    EXPECT_TRUE(merged.with_base_sync_primitives());
+  }
+  {
+    constexpr TaskTraits left = {};
+    constexpr TaskTraits right = {WithBaseSyncPrimitives()};
+    constexpr TaskTraits merged = TaskTraits::Merge(left, right);
+    EXPECT_FALSE(merged.priority_set_explicitly());
+    EXPECT_EQ(TaskPriority::USER_VISIBLE, merged.priority());
+    EXPECT_EQ(TaskShutdownBehavior::SKIP_ON_SHUTDOWN,
+              merged.shutdown_behavior());
+    EXPECT_FALSE(merged.may_block());
+    EXPECT_TRUE(merged.with_base_sync_primitives());
+  }
+}

[gab, 2017/05/09 14:32:31]

Also test a big override of all values with some overriden, some not, e.g. :

left = {MayBlock(), TaskPriority::BACKGROUND,
TaskShutdownBehavior::CONTINUE_ON_SHUTDOWN}

right = {WithBaseSyncPrimitives(), TaskPriority::USER_BLOCKING}

expected = {MayBlock(), WithBaseSyncPrimitives(), TaskPriority::USER_BLOCKING,
TaskShutdownBehavior::CONTINUE_ON_SHUTDOWN}

[fdoray, 2017/05/09 14:58:33]

Done.

+
 }  // namespace base