Create a FakeTetherService, which stubs out TetherService for development.

chrome/browser/chromeos/tether/tether_service_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 "chrome/browser/chromeos/tether/tether_service.h"
 
 #include <memory>
 
 #include "base/command_line.h"
 #include "base/memory/ptr_util.h"
@@ skipping 84 matching lines @@
   ~TetherServiceTest() override {}
 
   void SetUp() override {
     chromeos::DBusThreadManager::Initialize();
     chromeos::NetworkStateTest::SetUp();
 
     message_center::MessageCenter::Initialize();
     chromeos::NetworkConnect::Initialize(nullptr);
     chromeos::NetworkHandler::Initialize();
 
-    base::CommandLine::ForCurrentProcess()->AppendSwitch(
-        chromeos::switches::kEnableTether);
-
     TestingProfile::Builder builder;
     profile_ = builder.Build();
 
     fake_power_manager_client_ =
         base::MakeUnique<chromeos::FakePowerManagerClient>();
     fake_session_manager_client_ =
         base::MakeUnique<ExtendedFakeSessionManagerClient>();
 
     std::vector<cryptauth::ExternalDeviceInfo> test_device_infos;
     test_device_infos.push_back(cryptauth::ExternalDeviceInfo());
@@ skipping 109 matching lines @@
       network_state_handler()->GetTechnologyState(
           chromeos::NetworkTypePattern::Tether()));
 
   SetIsScreenLocked(false);
 
   EXPECT_EQ(chromeos::NetworkStateHandler::TechnologyState::TECHNOLOGY_ENABLED,
             network_state_handler()->GetTechnologyState(
                 chromeos::NetworkTypePattern::Tether()));
 }
 
-TEST_F(TetherServiceTest, TestFeatureFlag) {
-  base::CommandLine::Reset();
-  base::CommandLine::Init(0, nullptr);
+TEST_F(TetherServiceTest, TestFeatureFlagDisabled) {
+  EXPECT_FALSE(TetherService::Get(profile_.get()));
+}
 
-  CreateTetherService();
+TEST_F(TetherServiceTest, TestFeatureFlagEnabled) {
+  base::CommandLine::ForCurrentProcess()->AppendSwitch(
+      chromeos::switches::kEnableTether);
 
-  EXPECT_EQ(
-      chromeos::NetworkStateHandler::TechnologyState::TECHNOLOGY_UNAVAILABLE,
-      network_state_handler()->GetTechnologyState(
-          chromeos::NetworkTypePattern::Tether()));
+  TetherService* tether_service = TetherService::Get(profile_.get());
+  EXPECT_TRUE(tether_service);
+  tether_service->Shutdown();
 }
 
 TEST_F(TetherServiceTest, TestNoTetherHosts) {
   ON_CALL(*mock_cryptauth_device_manager_, GetTetherHosts())
       .WillByDefault(Return(std::vector<cryptauth::ExternalDeviceInfo>()));
 
   CreateTetherService();
 
   EXPECT_EQ(
       chromeos::NetworkStateHandler::TechnologyState::TECHNOLOGY_UNAVAILABLE,
@@ skipping 60 matching lines @@
   SetTetherTechnologyStateEnabled(false);
 
   EXPECT_EQ(1, tether_service_->updated_technology_state_count());
 
   SetTetherTechnologyStateEnabled(true);
   SetTetherTechnologyStateEnabled(true);
   SetTetherTechnologyStateEnabled(true);
 
   EXPECT_EQ(2, tether_service_->updated_technology_state_count());
 }