Test support for mocking audio::SystemInfo

This is another spin-off from WIP
https://chromium-review.googlesource.com/c/chromium/src/+/875927

See chrome/browser/chromeos/login/kiosk_browsertest.cc there for a use case.

Another (potential) use case is Speech Recognition browser tests here
https://cs.chromium.org/chromium/src/content/browser/speech/speech_recognition_browsertest.cc?type=cs&sq=package:chromium&l=132

Bug: 792441
Change-Id: I7c8b89bb1fc920ccade625dfc259e8c91edc8e94
Reviewed-on: https://chromium-review.googlesource.com/891184
Commit-Queue: Olga Sharonova <olka@chromium.org>
Reviewed-by: Ken Rockot <rockot@chromium.org>
Reviewed-by: Max Morin <maxmorin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#533621}

services/audio/BUILD.gn

@@ -46,6 +46,7 @@ source_set("tests") {
     "//base/test:test_support",
     "//media:test_support",
     "//services/audio/public/cpp",
+    "//services/audio/public/cpp:test_support",
     "//services/audio/public/interfaces",
     "//services/service_manager/public/cpp",
     "//services/service_manager/public/cpp:service_test_support",

services/audio/DEPS

@@ -2,4 +2,5 @@ include_rules = [
    "+media/audio",
    "+media/base",
    "+media/mojo",
+   "+services/audio/public",
 ]

services/audio/public/cpp/BUILD.gn

@@ -15,3 +15,19 @@ source_set("cpp") {
     "//services/service_manager/public/cpp",
   ]
 }
+
+source_set("test_support") {
+  testonly = true
+
+  sources = [
+    "fake_system_info.cc",
+    "fake_system_info.h",
+  ]
+
+  public_deps = [
+    "//base",
+    "//media",
+    "//services/audio/public/interfaces",
+    "//services/service_manager/public/cpp",
+  ]
+}

services/audio/public/cpp/fake_system_info.cc

+// Copyright 2018 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 "services/audio/public/cpp/fake_system_info.h"
+
+#include "services/audio/public/interfaces/constants.mojom.h"
+#include "services/service_manager/public/cpp/bind_source_info.h"
+#include "services/service_manager/public/cpp/service_context.h"
+
+namespace audio {
+
+FakeSystemInfo::FakeSystemInfo() {}
+
+FakeSystemInfo::~FakeSystemInfo() {}
+
+// static
+void FakeSystemInfo::OverrideGlobalBinderForAudioService(
+    FakeSystemInfo* fake_system_info) {
+  service_manager::ServiceContext::SetGlobalBinderForTesting(
+      mojom::kServiceName, mojom::SystemInfo::Name_,
+      base::BindRepeating(&FakeSystemInfo::Bind,
+                          base::Unretained(fake_system_info)));
+}
+
+void FakeSystemInfo::GetInputStreamParameters(
+    const std::string& device_id,
+    GetInputStreamParametersCallback callback) {
+  std::move(callback).Run(base::nullopt);
+}
+
+void FakeSystemInfo::GetOutputStreamParameters(
+    const std::string& device_id,
+    GetOutputStreamParametersCallback callback) {
+  std::move(callback).Run(base::nullopt);
+}
+
+void FakeSystemInfo::HasInputDevices(HasInputDevicesCallback callback) {
+  std::move(callback).Run(false);
+}
+
+void FakeSystemInfo::HasOutputDevices(HasOutputDevicesCallback callback) {
+  std::move(callback).Run(false);
+}
+
+void FakeSystemInfo::GetInputDeviceDescriptions(
+    GetInputDeviceDescriptionsCallback callback) {
+  std::move(callback).Run(media::AudioDeviceDescriptions());
+}
+
+void FakeSystemInfo::GetOutputDeviceDescriptions(
+    GetOutputDeviceDescriptionsCallback callback) {
+  std::move(callback).Run(media::AudioDeviceDescriptions());
+}
+
+void FakeSystemInfo::GetAssociatedOutputDeviceID(
+    const std::string& input_device_id,
+    GetAssociatedOutputDeviceIDCallback callback) {
+  std::move(callback).Run(base::nullopt);
+}
+
+void FakeSystemInfo::GetInputDeviceInfo(const std::string& input_device_id,
+                                        GetInputDeviceInfoCallback callback) {
+  std::move(callback).Run(base::nullopt, base::nullopt);
+}
+
+void FakeSystemInfo::Bind(const std::string& interface_name,
+                          mojo::ScopedMessagePipeHandle handle,
+                          const service_manager::BindSourceInfo& source_info) {
+  DCHECK(interface_name == mojom::SystemInfo::Name_);
+  bindings_.AddBinding(this, mojom::SystemInfoRequest(std::move(handle)));
+}
+
+}  // namespace audio

services/audio/public/cpp/fake_system_info.h

+// Copyright 2018 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.
+
+#ifndef SERVICES_AUDIO_PUBLIC_CPP_FAKE_SYSTEM_INFO_H_
+#define SERVICES_AUDIO_PUBLIC_CPP_FAKE_SYSTEM_INFO_H_
+
+#include <string>
+
+#include "base/macros.h"
+#include "mojo/public/cpp/bindings/binding_set.h"
+#include "mojo/public/cpp/system/message_pipe.h"
+#include "services/audio/public/interfaces/system_info.mojom.h"
+
+namespace service_manager {
+struct BindSourceInfo;
+}
+
+namespace audio {
+
+// An instance of this class can be used to override the global binding for
+// audio::SystemInfo. By default it behaves as if the system has no audio
+// devices. Inherit from it to override the behavior.
+class FakeSystemInfo : public mojom::SystemInfo {
+ public:
+  FakeSystemInfo();
+  ~FakeSystemInfo() override;
+
+  // See ServiceContext::ClearGlobalBindersForTesting() to clear it if needed.
+  static void OverrideGlobalBinderForAudioService(
+      FakeSystemInfo* fake_system_info);
+
+ protected:
+  // audio::mojom::SystemInfo implementation.
+  void GetInputStreamParameters(
+      const std::string& device_id,
+      GetInputStreamParametersCallback callback) override;
+  void GetOutputStreamParameters(
+      const std::string& device_id,
+      GetOutputStreamParametersCallback callback) override;
+  void HasInputDevices(HasInputDevicesCallback callback) override;
+  void HasOutputDevices(HasOutputDevicesCallback callback) override;
+  void GetInputDeviceDescriptions(
+      GetInputDeviceDescriptionsCallback callback) override;
+  void GetOutputDeviceDescriptions(
+      GetOutputDeviceDescriptionsCallback callback) override;
+  void GetAssociatedOutputDeviceID(
+      const std::string& input_device_id,
+      GetAssociatedOutputDeviceIDCallback callback) override;
+  void GetInputDeviceInfo(const std::string& input_device_id,
+                          GetInputDeviceInfoCallback callback) override;
+
+ private:
+  void Bind(const std::string& interface_name,
+            mojo::ScopedMessagePipeHandle handle,
+            const service_manager::BindSourceInfo& source_info);
+
+  mojo::BindingSet<mojom::SystemInfo> bindings_;
+  DISALLOW_COPY_AND_ASSIGN(FakeSystemInfo);
+};
+
+}  // namespace audio
+
+#endif  // SERVICES_AUDIO_PUBLIC_CPP_FAKE_SYSTEM_INFO_H_

services/audio/service_factory.cc

@@ -6,6 +6,7 @@
 
 #include "services/audio/in_process_audio_manager_accessor.h"
 #include "services/audio/service.h"
+#include "services/service_manager/public/cpp/service.h"
 
 namespace audio {
 

services/audio/service_factory.h

@@ -7,8 +7,9 @@
 
 #include <memory>
 
-#include "base/macros.h"
-#include "services/service_manager/public/cpp/service.h"
+namespace service_manager {
+class Service;
+}
 
 namespace media {
 class AudioManager;

services/audio/test/in_process_service_test.cc

@@ -7,6 +7,7 @@
 #include "media/audio/test_audio_thread.h"
 #include "mojo/public/cpp/bindings/binding_set.h"
 #include "services/audio/public/cpp/audio_system_to_service_adapter.h"
+#include "services/audio/public/cpp/fake_system_info.h"
 #include "services/audio/public/interfaces/constants.mojom.h"
 #include "services/audio/service_factory.h"
 #include "services/service_manager/public/cpp/service_context.h"
@@ -155,6 +156,36 @@ class InProcessServiceTest : public service_manager::test::ServiceTest {
   DISALLOW_COPY_AND_ASSIGN(InProcessServiceTest);
 };
 
+// Tests for FakeSystemInfo overriding the global binder.
+class FakeSystemInfoTest : public InProcessServiceTest<false>,
+                           public FakeSystemInfo {
+ public:
+  FakeSystemInfoTest() {}
+  ~FakeSystemInfoTest() override {}
+
+ protected:
+  MOCK_METHOD0(MethodCalled, void());
+
+ private:
+  void HasInputDevices(HasInputDevicesCallback callback) override {
+    std::move(callback).Run(true);
+    MethodCalled();
+  }
+
+  DISALLOW_COPY_AND_ASSIGN(FakeSystemInfoTest);
+};
+
+TEST_F(FakeSystemInfoTest, HasInputDevicesCalledOnGlobalBinderOverride) {
+  FakeSystemInfo::OverrideGlobalBinderForAudioService(this);
+  base::RunLoop wait_loop;
+  EXPECT_CALL(*this, MethodCalled())
+      .WillOnce(testing::Invoke(&wait_loop, &base::RunLoop::Quit));
+  audio_system()->HasInputDevices(base::BindOnce([](bool) {}));
+  wait_loop.Run();
+  service_manager::ServiceContext::ClearGlobalBindersForTesting(
+      mojom::kServiceName);
+}
+
 }  // namespace audio
 
 // AudioSystem interface conformance tests.