Add initial Fantom test for the basic global environment setup (#53268)

Summary:
Pull Request resolved: #53268

Changelog: [internal]

Adds tests for the global environment setup in RN.

Reviewed By: rshest

Differential Revision: D78415432

fbshipit-source-id: 8fdafee93ddbdf17770f3cb2069bf4834bb43dac

Author: rubennorte

packages/react-native/src/private/setup/__tests__/setUpDefaultReactNativeEnvironment-Globals-itest.js

@@ -0,0 +1,28 @@
+/**
+ * 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.
+ *
+ * @flow strict-local
+ * @format
+ * @oncall react_native
+ */
+
+import '@react-native/fantom/src/setUpDefaultReactNativeEnvironment';
+
+describe('setUpDefaultReactNativeEnvironment (globals)', () => {
+  it('should be exposed as globalThis, global, window and self', () => {
+    expect(globalThis).toBe(global);
+    expect(globalThis).toBe(window);
+    expect(globalThis).toBe(self);
+  });
+
+  it('should provide process.env.NODE_ENV', () => {
+    expect(process.env.NODE_ENV).toBe('development');
+  });
+
+  it('should provide the __DEV__ constant', () => {
+    expect(__DEV__).toBe(true);
+  });
+});