add unit tests for EventTarget (#41596)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/41596

changelog: [internal]

Reviewed By: rshest

Differential Revision: D51499449

fbshipit-source-id: 782108edf24af1c91d77c664bc496b466995621e

packages/react-native/ReactCommon/react/renderer/core/tests/EventTargetTests.cpp

@@ -0,0 +1,43 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#include <gtest/gtest.h>
+#include <hermes/hermes.h>
+#include <react/renderer/core/EventTarget.h>
+#include <react/renderer/core/InstanceHandle.h>
+
+using namespace facebook;
+using namespace facebook::react;
+
+TEST(EventTargetTests, getInstanceHandle) {
+  auto runtime = facebook::hermes::makeHermesRuntime();
+  auto object = jsi::Object(*runtime);
+  auto instanceHandle = std::make_shared<InstanceHandle>(
+      *runtime, jsi::Value(*runtime, object), 1);
+
+  EXPECT_EQ(instanceHandle->getTag(), 1);
+
+  auto eventTarget = EventTarget(std::move(instanceHandle));
+
+  EXPECT_EQ(eventTarget.getTag(), 1);
+
+  EXPECT_TRUE(eventTarget.getInstanceHandle(*runtime).isNull());
+
+  eventTarget.retain(*runtime);
+
+  EXPECT_TRUE(eventTarget.getInstanceHandle(*runtime).isNull());
+
+  eventTarget.setEnabled(true);
+
+  eventTarget.retain(*runtime);
+
+  EXPECT_FALSE(eventTarget.getInstanceHandle(*runtime).isNull());
+
+  eventTarget.release(*runtime);
+
+  EXPECT_TRUE(eventTarget.getInstanceHandle(*runtime).isNull());
+}