test

Author: dnfield

lib/ui/painting/path_unittests.cc

@@ -124,5 +124,62 @@ TEST_F(ShellTest, PathVolatilityGCRemovesPathFromTracker) {
   DestroyShell(std::move(shell), std::move(task_runners));
 }
 
+// Screen diffing tests use deterministic rendering. Allowing a path to be
+// volatile or not for an individual frame can result in minor pixel differences
+// that cause the test to fail.
+// If deterministic rendering is enabled, the tracker should be disabled and
+// paths should always be non-volatile.
+TEST_F(ShellTest, DeterministicRenderingDisablesPathVolatility) {
+  auto message_latch = std::make_shared<fml::AutoResetWaitableEvent>();
+
+  auto native_validate_path = [message_latch](Dart_NativeArguments args) {
+    auto handle = Dart_GetNativeArgument(args, 0);
+    intptr_t peer = 0;
+    Dart_Handle result = Dart_GetNativeInstanceField(
+        handle, tonic::DartWrappable::kPeerIndex, &peer);
+    EXPECT_FALSE(Dart_IsError(result));
+    CanvasPath* path = reinterpret_cast<CanvasPath*>(peer);
+    EXPECT_TRUE(path);
+    EXPECT_FALSE(path->path().isVolatile());
+    std::shared_ptr<VolatilePathTracker> tracker =
+        UIDartState::Current()->GetVolatilePathTracker();
+    EXPECT_TRUE(tracker);
+    EXPECT_FALSE(tracker->enabled());
+
+    for (int i = 0; i < VolatilePathTracker::kFramesOfVolatility; i++) {
+      tracker->OnFrame();
+      EXPECT_FALSE(path->path().isVolatile());
+    }
+    EXPECT_FALSE(path->path().isVolatile());
+    message_latch->Signal();
+  };
+
+  Settings settings = CreateSettingsForFixture();
+  settings.skia_deterministic_rendering_on_cpu = true;
+  TaskRunners task_runners("test",                  // label
+                           GetCurrentTaskRunner(),  // platform
+                           CreateNewThread(),       // raster
+                           CreateNewThread(),       // ui
+                           CreateNewThread()        // io
+  );
+
+  AddNativeCallback("ValidatePath", CREATE_NATIVE_ENTRY(native_validate_path));
+
+  std::unique_ptr<Shell> shell =
+      CreateShell(std::move(settings), std::move(task_runners));
+
+  ASSERT_TRUE(shell->IsSetup());
+  auto configuration = RunConfiguration::InferFromSettings(settings);
+  configuration.SetEntrypoint("createPath");
+
+  shell->RunEngine(std::move(configuration), [](auto result) {
+    ASSERT_EQ(result, Engine::RunStatus::Success);
+  });
+
+  message_latch->Wait();
+
+  DestroyShell(std::move(shell), std::move(task_runners));
+}
+
 }  // namespace testing
 }  // namespace flutter

lib/ui/volatile_path_tracker.h

@@ -62,6 +62,8 @@ class VolatilePathTracker {
   // Must be called from the UI task runner.
   void OnFrame();
 
+  bool enabled() const { return enabled_; }
+
  private:
   fml::RefPtr<fml::TaskRunner> ui_task_runner_;
   std::atomic_bool needs_drain_ = false;