Add smoke test for UsbService::GetDevices.

device/usb/usb_service_unittest.cc

 // Copyright 2014 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 <memory>
 
+#include "base/bind.h"
 #include "base/message_loop/message_loop.h"
+#include "base/run_loop.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/test/test_io_thread.h"
 #include "device/test/test_device_client.h"
 #include "device/test/usb_test_gadget.h"
 #include "device/usb/usb_device.h"
-#include "device/usb/usb_device_handle.h"
+#include "device/usb/usb_service.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace device {
 
 namespace {
 
 class UsbServiceTest : public ::testing::Test {
  public:
   void SetUp() override {
     message_loop_.reset(new base::MessageLoopForUI);
     io_thread_.reset(new base::TestIOThread(base::TestIOThread::kAutoStart));
     device_client_.reset(new TestDeviceClient(io_thread_->task_runner()));
   }
 
  protected:
   std::unique_ptr<base::MessageLoop> message_loop_;
   std::unique_ptr<base::TestIOThread> io_thread_;
   std::unique_ptr<TestDeviceClient> device_client_;
 };
 
+void OnGetDevices(const base::Closure& quit_closure,
+                  const std::vector<scoped_refptr<UsbDevice>>& devices) {
+  quit_closure.Run();
+}
+
+TEST_F(UsbServiceTest, GetDevices) {
+  // Since there's no guarantee that any devices are connected at the moment
+  // this test doesn't assume anything about the result but it at least verifies
+  // that devices can be enumerated without the application crashing.
+  UsbService* service = device_client_->GetUsbService();
+  if (service) {
+    base::RunLoop loop;
+    service->GetDevices(base::Bind(&OnGetDevices, loop.QuitClosure()));
+    loop.Run();
+  }
+}
+
 TEST_F(UsbServiceTest, ClaimGadget) {
   if (!UsbTestGadget::IsTestEnabled()) return;
 
   std::unique_ptr<UsbTestGadget> gadget =
       UsbTestGadget::Claim(io_thread_->task_runner());
   ASSERT_TRUE(gadget.get());
 
   scoped_refptr<UsbDevice> device = gadget->GetDevice();
   ASSERT_EQ("Google Inc.", base::UTF16ToUTF8(device->manufacturer_string()));
   ASSERT_EQ("Test Gadget (default state)",
             base::UTF16ToUTF8(device->product_string()));
 }
 
 TEST_F(UsbServiceTest, DisconnectAndReconnect) {
   if (!UsbTestGadget::IsTestEnabled()) return;
 
   std::unique_ptr<UsbTestGadget> gadget =
       UsbTestGadget::Claim(io_thread_->task_runner());
   ASSERT_TRUE(gadget.get());
   ASSERT_TRUE(gadget->Disconnect());
   ASSERT_TRUE(gadget->Reconnect());
 }
 
 }  // namespace
 
 }  // namespace device