Add unit test for common parsers method (#34915)

Summary:
This PR is part of #34872
This PR adds unit test for method that were refactored into parsers-commons.js in codegen in #34898

## Changelog

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[Internal] [Changed] - Add unit test for common parsers method

Pull Request resolved: #34915

Test Plan: `yarn jest react-native-codegen`

Reviewed By: cipolleschi

Differential Revision: D40219036

Pulled By: cipolleschi

fbshipit-source-id: 2fb666c016f7822feaf2156d23ce7ffb9572c756

packages/react-native-codegen/src/parsers/__tests__/parsers-commons-test.js

@@ -0,0 +1,80 @@
+/**
+ * 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
+ */
+
+'use-strict';
+
+const {wrapNullable, unwrapNullable} = require('../parsers-commons.js');
+
+describe('wrapNullable', () => {
+  describe('when nullable is true', () => {
+    it('returns nullable type annotation', () => {
+      const result = wrapNullable(true, {
+        type: 'BooleanTypeAnnotation',
+      });
+      const expected = {
+        type: 'NullableTypeAnnotation',
+        typeAnnotation: {
+          type: 'BooleanTypeAnnotation',
+        },
+      };
+
+      expect(result).toEqual(expected);
+    });
+  });
+  describe('when nullable is false', () => {
+    it('returns non nullable type annotation', () => {
+      const result = wrapNullable(false, {
+        type: 'BooleanTypeAnnotation',
+      });
+      const expected = {
+        type: 'BooleanTypeAnnotation',
+      };
+
+      expect(result).toEqual(expected);
+    });
+  });
+});
+
+describe('unwrapNullable', () => {
+  describe('when type annotation is nullable', () => {
+    it('returns original type annotation', () => {
+      const result = unwrapNullable({
+        type: 'NullableTypeAnnotation',
+        typeAnnotation: {
+          type: 'BooleanTypeAnnotation',
+        },
+      });
+      const expected = [
+        {
+          type: 'BooleanTypeAnnotation',
+        },
+        true,
+      ];
+
+      expect(result).toEqual(expected);
+    });
+  });
+  describe('when type annotation is not nullable', () => {
+    it('returns original type annotation', () => {
+      const result = unwrapNullable({
+        type: 'BooleanTypeAnnotation',
+      });
+      const expected = [
+        {
+          type: 'BooleanTypeAnnotation',
+        },
+        false,
+      ];
+
+      expect(result).toEqual(expected);
+    });
+  });
+});