Added unit tests to the engine.

ci/licenses_golden/licenses_flutter

@@ -600,6 +600,7 @@ FILE: ../../../flutter/shell/common/canvas_spy.h
 FILE: ../../../flutter/shell/common/canvas_spy_unittests.cc
 FILE: ../../../flutter/shell/common/engine.cc
 FILE: ../../../flutter/shell/common/engine.h
+FILE: ../../../flutter/shell/common/engine_unittests.cc
 FILE: ../../../flutter/shell/common/fixtures/shell_test.dart
 FILE: ../../../flutter/shell/common/fixtures/shelltest_screenshot.png
 FILE: ../../../flutter/shell/common/input_events_unittests.cc

runtime/runtime_controller.cc

@@ -16,6 +16,10 @@
 
 namespace flutter {
 
+RuntimeController::RuntimeController(RuntimeDelegate& client,
+                                     TaskRunners p_task_runners)
+    : client_(client), vm_(nullptr), task_runners_(p_task_runners) {}
+
 RuntimeController::RuntimeController(
     RuntimeDelegate& p_client,
     DartVM* p_vm,

runtime/runtime_controller.h

@@ -38,7 +38,7 @@ class Window;
 /// used by the engine to copy the currently accumulated window state so it can
 /// be referenced by the new runtime controller.
 ///
-class RuntimeController final : public PlatformConfigurationClient {
+class RuntimeController : public PlatformConfigurationClient {
  public:
   //----------------------------------------------------------------------------
   /// @brief      Creates a new instance of a runtime controller. This is
@@ -340,7 +340,7 @@ class RuntimeController final : public PlatformConfigurationClient {
   ///
   /// @return     True if root isolate running, False otherwise.
   ///
-  bool IsRootIsolateRunning() const;
+  virtual bool IsRootIsolateRunning() const;
 
   //----------------------------------------------------------------------------
   /// @brief      Dispatch the specified platform message to running root
@@ -351,7 +351,7 @@ class RuntimeController final : public PlatformConfigurationClient {
   /// @return     If the message was dispatched to the running root isolate.
   ///             This may fail is an isolate is not running.
   ///
-  bool DispatchPlatformMessage(fml::RefPtr<PlatformMessage> message);
+  virtual bool DispatchPlatformMessage(fml::RefPtr<PlatformMessage> message);
 
   //----------------------------------------------------------------------------
   /// @brief      Dispatch the specified pointer data message to the running
@@ -440,6 +440,10 @@ class RuntimeController final : public PlatformConfigurationClient {
   ///
   std::pair<bool, uint32_t> GetRootIsolateReturnCode();
 
+ protected:
+  /// Constructor for Mocks.
+  RuntimeController(RuntimeDelegate& client, TaskRunners p_task_runners);
+
  private:
   struct Locale {
     Locale(std::string language_code_,

shell/common/BUILD.gn

@@ -258,6 +258,7 @@ if (enable_unittests) {
     sources = [
       "animator_unittests.cc",
       "canvas_spy_unittests.cc",
+      "engine_unittests.cc",
       "input_events_unittests.cc",
       "persistent_cache_unittests.cc",
       "pipeline_unittests.cc",
@@ -268,6 +269,7 @@ if (enable_unittests) {
     deps = [
       "//flutter/assets",
       "//flutter/shell/version",
+      "//third_party/googletest:gmock",
     ]
 
     public_deps_legacy_and_next = [ ":shell_test_fixture_sources" ]

shell/common/engine.cc

@@ -35,6 +35,27 @@ static constexpr char kLocalizationChannel[] = "flutter/localization";
 static constexpr char kSettingsChannel[] = "flutter/settings";
 static constexpr char kIsolateChannel[] = "flutter/isolate";
 
+Engine::Engine(
+    Delegate& delegate,
+    const PointerDataDispatcherMaker& dispatcher_maker,
+    std::shared_ptr<fml::ConcurrentTaskRunner> image_decoder_task_runner,
+    TaskRunners task_runners,
+    Settings settings,
+    std::unique_ptr<Animator> animator,
+    fml::WeakPtr<IOManager> io_manager,
+    std::unique_ptr<RuntimeController> runtime_controller)
+    : delegate_(delegate),
+      settings_(std::move(settings)),
+      animator_(std::move(animator)),
+      runtime_controller_(std::move(runtime_controller)),
+      activity_running_(true),
+      have_surface_(false),
+      image_decoder_(task_runners, image_decoder_task_runner, io_manager),
+      task_runners_(std::move(task_runners)),
+      weak_factory_(this) {
+  pointer_data_dispatcher_ = dispatcher_maker(*this);
+}
+
 Engine::Engine(Delegate& delegate,
                const PointerDataDispatcherMaker& dispatcher_maker,
                DartVM& vm,
@@ -46,19 +67,14 @@ Engine::Engine(Delegate& delegate,
                fml::WeakPtr<IOManager> io_manager,
                fml::RefPtr<SkiaUnrefQueue> unref_queue,
                fml::WeakPtr<SnapshotDelegate> snapshot_delegate)
-    : delegate_(delegate),
-      settings_(std::move(settings)),
-      animator_(std::move(animator)),
-      activity_running_(true),
-      have_surface_(false),
-      image_decoder_(task_runners,
-                     vm.GetConcurrentWorkerTaskRunner(),
-                     io_manager),
-      task_runners_(std::move(task_runners)),
-      weak_factory_(this) {
-  // Runtime controller is initialized here because it takes a reference to this
-  // object as its delegate. The delegate may be called in the constructor and
-  // we want to be fully initilazed by that point.
+    : Engine(delegate,
+             dispatcher_maker,
+             vm.GetConcurrentWorkerTaskRunner(),
+             task_runners,
+             settings,
+             std::move(animator),
+             io_manager,
+             nullptr) {
   runtime_controller_ = std::make_unique<RuntimeController>(
       *this,                        // runtime delegate
       &vm,                          // VM
@@ -76,8 +92,6 @@ Engine::Engine(Delegate& delegate,
       settings_.isolate_shutdown_callback,   // isolate shutdown callback
       settings_.persistent_isolate_data      // persistent isolate data
   );
-
-  pointer_data_dispatcher_ = dispatcher_maker(*this);
 }
 
 Engine::~Engine() = default;

shell/common/engine.h

@@ -248,6 +248,20 @@ class Engine final : public RuntimeDelegate, PointerDataDispatcher::Delegate {
         const std::vector<std::string>& supported_locale_data) = 0;
   };
 
+  //----------------------------------------------------------------------------
+  /// @brief      Creates an instance of the engine with a supplied
+  ///             `RuntimeController`.  Use the other constructor except for
+  ///             tests.
+  ///
+  Engine(Delegate& delegate,
+         const PointerDataDispatcherMaker& dispatcher_maker,
+         std::shared_ptr<fml::ConcurrentTaskRunner> image_decoder_task_runner,
+         TaskRunners task_runners,
+         Settings settings,
+         std::unique_ptr<Animator> animator,
+         fml::WeakPtr<IOManager> io_manager,
+         std::unique_ptr<RuntimeController> runtime_controller);
+
   //----------------------------------------------------------------------------
   /// @brief      Creates an instance of the engine. This is done by the Shell
   ///             on the UI task runner.
@@ -756,6 +770,12 @@ class Engine final : public RuntimeDelegate, PointerDataDispatcher::Delegate {
   ///
   const std::string& GetLastEntrypointLibrary() const;
 
+  //----------------------------------------------------------------------------
+  /// @brief      Getter for the initial route.  This can be set with a platform
+  ///             message.
+  ///
+  const std::string& InitialRoute() const { return initial_route_; }
+
  private:
   Engine::Delegate& delegate_;
   const Settings settings_;