Add a mock class for DiskMountManagerObserver. disk_mount_manager_observer_unittests will be rewrit…

chromeos/disks/mock_disk_mount_manager_observer.h

Index: chromeos/disks/mock_disk_mount_manager_observer.h
diff --git a/chromeos/disks/mock_disk_mount_manager_observer.h b/chromeos/disks/mock_disk_mount_manager_observer.h
new file mode 100644
index 0000000000000000000000000000000000000000..0f5ae47ea09aaab8c47a28658ee5976621636ed6
--- /dev/null
+++ b/chromeos/disks/mock_disk_mount_manager_observer.h
@@ -0,0 +1,231 @@
+// Copyright (c) 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.
+
+#ifndef CHROMEOS_DISKS_MOCK_DISK_MOUNT_MANAGER_OBSERVER_H_
+#define CHROMEOS_DISKS_MOCK_DISK_MOUNT_MANAGER_OBSERVER_H_
+
+#include <memory>
+#include <string>
+#include <vector>
+
+#include "chromeos/disks/disk_mount_manager.h"
+using chromeos::disks::DiskMountManager;
+
+namespace chromeos {
+namespace disks {
+
+// Event classes which represents each invocation of functions in |Observer|.
+// OnDeviceEvent()
+class DeviceEvent {
+ public:
+  DeviceEvent() {}
+  ~DeviceEvent() {}
+
+  DeviceEvent(DiskMountManager::DeviceEvent event,
+              const std::string& device_path)
+      : event_(event), device_path_(device_path) {}
+
+  DeviceEvent(const DeviceEvent& other)
+      : event_(other.event_), device_path_(other.device_path_) {}
+
+  bool operator==(const DeviceEvent& other) const {
+    return event_ == other.event_ && device_path_ == other.device_path_;
+  }
+
+  DiskMountManager::DeviceEvent GetEvent() const { return event_; }
+
+  const std::string& GetDevicePath() const { return device_path_; }
+
+  std::string DebugString() const;
+
+ private:
+  DiskMountManager::DeviceEvent event_;
+  std::string device_path_;
+};
+
+// OnDiskEvent()
+class DiskEvent {
+ public:
+  DiskEvent() {}
+
+  DiskEvent(DiskMountManager::DiskEvent event,
+            const DiskMountManager::Disk* disk)
+      : event_(event), disk_(disk) {}
+
+  DiskEvent(const DiskEvent& other)
+      : event_(other.event_), disk_(other.disk_) {}
+
+  DiskEvent& operator=(const DiskEvent& other) {
+    event_ = other.event_;
+    disk_ = other.disk_;
+    return *this;
+  }
+
+  bool operator==(const DiskEvent& other) const {
+    return event_ == other.event_ && disk_ == other.disk_;
+  }
+
+  std::string DebugString() const;
+
+ private:
+  DiskMountManager::DiskEvent event_;
+  const DiskMountManager::Disk* disk_;
+};
+
+// OnFormatEvent()
+class FormatEvent {
+ public:
+  FormatEvent() {}
+  FormatEvent(DiskMountManager::FormatEvent event,
+              chromeos::FormatError error_code,
+              const std::string& device_path)
+      : event_(event), error_code_(error_code), device_path_(device_path) {}
+
+  bool operator==(const FormatEvent& other) const {
+    return event_ == other.event_ && error_code_ == other.error_code_ &&
+           device_path_ == other.device_path_;
+  }
+
+  DiskMountManager::FormatEvent GetEvent() const { return event_; }
+
+  chromeos::FormatError GetErrorCode() const { return error_code_; }
+
+  const std::string& GetDevicePath() const { return device_path_; }
+
+  std::string DebugString() const;
+
+ private:
+  DiskMountManager::FormatEvent event_;
+  chromeos::FormatError error_code_;
+  std::string device_path_;
+};
+
+// OnMountEvent()
+class MountEvent {
+ public:
+  DiskMountManager::MountEvent GetEvent() { return event_; }
+  chromeos::MountError GetErrorCode() { return error_code_; }
+  const DiskMountManager::MountPointInfo& GetMountPoint() {
+    return mount_point_;
+  }
+  MountEvent();
+  MountEvent(const MountEvent& other);
+  MountEvent(DiskMountManager::MountEvent event,
+             chromeos::MountError error_code,
+             const DiskMountManager::MountPointInfo& mount_point,
+             std::shared_ptr<DiskMountManager::Disk> disk);
+  ~MountEvent();
+  bool operator==(const MountEvent& other) const;
+  std::string DebugString() const;
+
+ private:
+  DiskMountManager::MountEvent event_;
+  chromeos::MountError error_code_;
+  DiskMountManager::MountPointInfo mount_point_;
+
+  // Not passed to callback, but read by handlers. So it's captured upon
+  // callback.
+  std::shared_ptr<DiskMountManager::Disk> disk_;
+};
+
+// Represents every event notified to |Observer|.
+class ObserverEvent {
+ private:
+  struct Event {
+    DeviceEvent device;
+    DiskEvent disk;
+    FormatEvent format;
+    MountEvent mount;
+    Event();
+    Event(const Event& other);
+    ~Event() {}
+  } event_;
+  ObserverEvent() {}
+
+ public:
+  enum ObserverEventType {
+    DEVICE_EVENT,
+    DISK_EVENT,
+    FORMAT_EVENT,
+    MOUNT_EVENT
+  } type_;
+
+  static ObserverEvent FromDeviceEvent(DeviceEvent event);
+  static ObserverEvent FromDiskEvent(DiskEvent event);
+  static ObserverEvent FromFormatEvent(FormatEvent event);
+  static ObserverEvent FromMountEvent(MountEvent event);
+
+  ObserverEvent(const ObserverEvent& other) : type_(other.type_) {
+    switch (other.type_) {
+      case DEVICE_EVENT:
+        event_.device = other.event_.device;
+        break;
+      case DISK_EVENT:
+        event_.disk = other.event_.disk;
+        break;
+      case FORMAT_EVENT:
+        event_.format = other.event_.format;
+        break;
+      case MOUNT_EVENT:
+        event_.mount = other.event_.mount;
+        break;
+    }
+  }
+
+  Event GetEvent() { return event_; }
+
+  ObserverEventType GetType() { return type_; }
+};
+
+// A mock |Observer| class which records all invocation of the methods invoked
+// from DiskMountManager and all the arguments passed to them.
+class MockDiskMountManagerObserver : public DiskMountManager::Observer {
+ public:
+  MockDiskMountManagerObserver(const DiskMountManager* manager);
+  ~MockDiskMountManagerObserver() override;
+
+  // Mock notify methods.
+  void OnDeviceEvent(DiskMountManager::DeviceEvent event,
+                     const std::string& device_path) override;
+
+  void OnDiskEvent(DiskMountManager::DiskEvent event,
+                   const DiskMountManager::Disk* disk) override;
+
+  void OnMountEvent(
+      DiskMountManager::MountEvent event,
+      chromeos::MountError error_code,
+      const DiskMountManager::MountPointInfo& mount_point) override;
+
+  void OnFormatEvent(DiskMountManager::FormatEvent event,
+                     chromeos::FormatError error_code,
+                     const std::string& device_path) override;
+
+  // Get invocation history to be verified by testcases.
+  DeviceEvent GetDeviceEvent(size_t index);

[yamaguchi, 2016/08/30 02:20:10]

It'd be easier to have tests get and verify ObserverEvents objects rather than
doing such for individual types for each event type.
Hide these 4 functions and implement comparator and DebugString() in
ObserverEvent, so that the tests can verify results like:
ASSERT_EQ(ObserverEvent::FromDeviceEvent(...), observer_.GetEvent(1));

[yamaguchi, 2016/08/30 04:39:50]

In the current unit test, MountEvent is not examined for all fields. The tests
examine only 1 field using testing::Field (within gmock EXPECT_CALL), and it
would be reasonable for the purpose of the test. Such test will be rewritten
using this class by GetMountEvent() first and then EXPECT_EQ for each field in
it. So I think we don't need to implement euqals (==) for all events now.

Example:
https://cs.chromium.org/chromium/src/chromeos/disks/disk_mount_manager_unitte...

+  FormatEvent GetFormatEvent(size_t index);
+  DiskEvent GetDiskEvent(size_t index);
+  MountEvent GetMountEvent(size_t index);
+
+  size_t GetEventCount() { return events_.size(); }
+
+  ObserverEvent GetEvent(size_t index) { return events_.at(index); }
+
+ private:
+  // Pointer to the manager object to which this |Observer| is registered.
+  const DiskMountManager* manager_;
+
+  // Records all invocations.
+  std::vector<ObserverEvent> events_;
+};
+
+// Needed to print values in case of EXPECT_* failure in gtest.
+std::ostream& operator<<(std::ostream& stream, const DeviceEvent& device_event);
+std::ostream& operator<<(std::ostream& stream, const DiskEvent& disk_event);
+std::ostream& operator<<(std::ostream& stream, const FormatEvent& format_event);
+std::ostream& operator<<(std::ostream& stream, const MountEvent& mount_event);
+
+}  // namespace disks
+}  // namespace chromeos
+
+#endif  // CHROMEOS_DISKS_MOCK_DISK_MOUNT_MANAGER_OBSERVER_H_