adding jest test cases

Taken from my previous pr https://github.com/facebook/react-native/pull/31199/files

Libraries/Components/Switch/__tests__/Switch-test.js

@@ -0,0 +1,96 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @format
+ * @emails oncall+react_native
+ * @flow strict-local
+ */
+
+import * as React from 'react';
+
+import Switch from '../Switch';
+import View from '../../View/View';
+import {expectRendersMatchingSnapshot} from '../../../Utilities/ReactNativeTestTools';
+
+describe('<Switch />', () => {
+  it('should render as expected', () => {
+    expectRendersMatchingSnapshot(
+      'Switch',
+      () => (
+        <Switch>
+          <View />
+        </Switch>
+      ),
+      () => {
+        jest.dontMock('../Switch');
+      },
+    );
+  });
+});
+
+describe('<Switch disabled={true} />', () => {
+  it('should be disabled when disabled is true', () => {
+    expectRendersMatchingSnapshot(
+      'Switch',
+      () => (
+        <Switch disabled={true}>
+          <View />
+        </Switch>
+      ),
+      () => {
+        jest.dontMock('../Switch');
+      },
+    );
+  });
+});
+
+describe('<Switch disabled={true} accessibilityState={{}} />', () => {
+  it('should be disabled when disabled is true and accessibilityState is empty', () => {
+    expectRendersMatchingSnapshot(
+      'Switch',
+      () => (
+        <Switch disabled={true} accessibilityState={{}}>
+          <View />
+        </Switch>
+      ),
+      () => {
+        jest.dontMock('../Switch');
+      },
+    );
+  });
+});
+
+describe('<Switch disabled={true} accessibilityState={{checked: true}} />', () => {
+  it('should keep accessibilityState when disabled is true', () => {
+    expectRendersMatchingSnapshot(
+      'Switch',
+      () => (
+        <Switch disabled={true} accessibilityState={{checked: true}}>
+          <View />
+        </Switch>
+      ),
+      () => {
+        jest.dontMock('../Switch');
+      },
+    );
+  });
+});
+
+describe('<Switch disabled={true} accessibilityState={{disabled: false}} />', () => {
+  it('should overwrite accessibilityState with value of disabled prop', () => {
+    expectRendersMatchingSnapshot(
+      'Switch',
+      () => (
+        <Switch disabled={true} accessibilityState={{disabled: false}}>
+          <View />
+        </Switch>
+      ),
+      () => {
+        jest.dontMock('../Switch');
+      },
+    );
+  });
+});