Control TaskScheduler initialization params in renderers via field trial.

components/task_scheduler_util/common/variations_util_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 "components/task_scheduler_util/common/variations_util.h"
 
 #include <map>
 #include <string>
 #include <vector>
 
+#include "base/command_line.h"
 #include "base/task_scheduler/scheduler_worker_pool_params.h"
 #include "base/threading/platform_thread.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace task_scheduler_util {
 
 namespace {
 
 using StandbyThreadPolicy =
     base::SchedulerWorkerPoolParams::StandbyThreadPolicy;
 using ThreadPriority = base::ThreadPriority;
 
+constexpr char kTaskSchedulerVariationParamsSwitch[] =
+    "task-scheduler-variation-params";
+
 std::vector<SchedulerConstantWorkerPoolParams> GetConstantWorkerPoolParams() {
   std::vector<SchedulerConstantWorkerPoolParams> constant_worker_pool_params;
   constant_worker_pool_params.emplace_back("Background",
                                            ThreadPriority::BACKGROUND);
   constant_worker_pool_params.emplace_back("BackgroundFileIO",
                                            ThreadPriority::BACKGROUND);
   constant_worker_pool_params.emplace_back("Foreground",
                                            ThreadPriority::NORMAL);
   constant_worker_pool_params.emplace_back("ForegroundFileIO",
                                            ThreadPriority::NORMAL);
@@ skipping 105 matching lines @@
   std::map<std::string, std::string> variation_params;
   variation_params["Background"] = "a;b;c;d;e";
   variation_params["BackgroundFileIO"] = "a;b;c;d;e";
   variation_params["Foreground"] = "a;b;c;d;e";
   variation_params["ForegroundFileIO"] = "a;b;c;d;e";
   EXPECT_TRUE(
       GetWorkerPoolParams(GetConstantWorkerPoolParams(), variation_params)
           .empty());
 }
 
+TEST(TaskSchedulerUtilVariationsUtilTest, CommandLine) {
+  std::map<std::string, std::string> in_variation_params;
+  in_variation_params["PrefixFoo"] = "Foo";
+  in_variation_params["PrefixBar"] = "Bar";
+  in_variation_params["NoPrefix"] = "NoPrefix";
+
+  base::CommandLine command_line(base::CommandLine::NO_PROGRAM);
+  AddVariationParamsToCommandLine(in_variation_params, "Prefix", &command_line);
+  const std::map<std::string, std::string> out_variation_params =
+      GetVariationParamsFromCommandLine(command_line);
+
+  std::map<std::string, std::string> expected_out_variation_params;
+  expected_out_variation_params["PrefixFoo"] = "Foo";
+  expected_out_variation_params["PrefixBar"] = "Bar";
+  EXPECT_EQ(expected_out_variation_params, out_variation_params);
+}
+
+TEST(TaskSchedulerUtilVariationsUtilTest,
+     CommandLineSeparatorInVariationParamsKey) {
+  std::map<std::string, std::string> in_variation_params;
+  in_variation_params["PrefixFoo"] = "Foo";
+  in_variation_params["PrefixKey|"] = "Value";
+
+  base::CommandLine command_line(base::CommandLine::NO_PROGRAM);
+  AddVariationParamsToCommandLine(in_variation_params, "Prefix", &command_line);
+  EXPECT_TRUE(
+      command_line.GetSwitchValueASCII(kTaskSchedulerVariationParamsSwitch)
+          .empty());
+}
+
+TEST(TaskSchedulerUtilVariationsUtilTest,
+     CommandLineSeparatorInVariationParamsValue) {
+  std::map<std::string, std::string> in_variation_params;
+  in_variation_params["PrefixFoo"] = "Foo";
+  in_variation_params["PrefixKey"] = "Value|";
+
+  base::CommandLine command_line(base::CommandLine::NO_PROGRAM);
+  AddVariationParamsToCommandLine(in_variation_params, "Prefix", &command_line);
+  EXPECT_TRUE(
+      command_line.GetSwitchValueASCII(kTaskSchedulerVariationParamsSwitch)
+          .empty());
+}
+
+TEST(TaskSchedulerUtilVariationsUtilTest, CommandLineInvalidSwitch) {
+  base::CommandLine command_line(base::CommandLine::NO_PROGRAM);
+  command_line.AppendSwitchASCII(kTaskSchedulerVariationParamsSwitch,
+                                 "one|two|three");
+  EXPECT_TRUE(GetVariationParamsFromCommandLine(command_line).empty());
+}
+
+TEST(TaskSchedulerUtilVariationsUtilTest, CommandLineEmptySwitch) {
+  base::CommandLine command_line(base::CommandLine::NO_PROGRAM);
+  command_line.AppendSwitchASCII(kTaskSchedulerVariationParamsSwitch, "");
+  EXPECT_TRUE(GetVariationParamsFromCommandLine(command_line).empty());
+}
+
+TEST(TaskSchedulerUtilVariationsUtilTest, CommandLineNoSwitch) {
+  base::CommandLine command_line(base::CommandLine::NO_PROGRAM);
+  EXPECT_TRUE(GetVariationParamsFromCommandLine(command_line).empty());
+}

[gab, 2016/12/12 17:33:33]

I wouldn't bother testing all invalid inputs. I think it's fine to assume valid
input (i.e. use NOTREACHED() to document it's impossible to get there with
expected input and don't test it).

I think we should test:

1) Mapping variations with no BrowserScheduler* results in no-op.

2) Mapping variations with BrowserScheduler* WAI.

[gab, 2017/01/05 18:40:05]

ping

[fdoray, 2017/01/06 17:29:03]

~ done. I think you didn't correctly understand the purpose of the |prefix|. See
https://codereview.chromium.org/2568793003/diff/20001/components/task_schedul...

+
 }  // namespace task_scheduler_util