Add asset utils resource identifier tests (#57999)

Summary:
Adds test coverage for `getAndroidResourceIdentifier` in `react-native/asset-utils`.

The tests cover folder path encoding, Android resource-name normalization, and generated asset path prefix removal.

## Changelog:
[INTERNAL] - Add test coverage for asset utils Android resource identifier normalization

Pull Request resolved: https://github.com/react/react-native/pull/57999

Test Plan:
Ran the package suite on this rebased commit:

```
yarn jest packages/asset-utils
# 1 suite, 7 passed (4 pre-existing, 3 new)
```

Checked that the three new cases are non-vacuous by mutating
`packages/asset-utils/src/AndroidPathUtils.js` one change at a time and re-running:

| mutation | result |
| --- | --- |
| narrow the prefix regex to `^assets_` | 1 failed, 6 passed |
| drop the `[^a-z0-9_]` illegal-char strip | 1 failed, 6 passed |
| drop `toLowerCase()` | 1 failed, 6 passed |
| restored | 7 passed |

Each new test kills exactly one distinct mutant, so all three assert real behavior
rather than padding coverage. The `^assets_` case matters most: the real regex is
`^(?:assets|assetsunstable_path)_`, where the first alternative matches `assets` then
fails on the following character, so the second alternative has to carry it.

This PR only adds `describe` blocks to an existing test file that was already running,
so there is no new test target to register.

Reviewed By: christophpurrer

Differential Revision: D117191484

Pulled By: fabriziocucci

fbshipit-source-id: 7a13c01772669eaf0ddfdf29156d8f250fd5cada

packages/asset-utils/src/__tests__/AndroidPathUtils-test.js

@@ -8,7 +8,10 @@
  * @format
  */
 
-import {getAndroidResourceFolderName} from '../AndroidPathUtils';
+import {
+  getAndroidResourceFolderName,
+  getAndroidResourceIdentifier,
+} from '../AndroidPathUtils';
 
 const DRAWABLE_ASSET = {
   httpServerLocation: '/assets/',
@@ -70,3 +73,35 @@ describe('getAndroidResourceFolderName', () => {
     expect(getAndroidResourceFolderName(NON_DRAWABLE_ASSET, 1.25)).toBe('raw');
   });
 });
+
+describe('getAndroidResourceIdentifier', () => {
+  test('encodes folder structure in the resource name', () => {
+    expect(
+      getAndroidResourceIdentifier({
+        httpServerLocation: '/assets/images/icons',
+        name: 'search',
+        type: 'png',
+      }),
+    ).toBe('images_icons_search');
+  });
+
+  test('normalizes resource names to Android identifier characters', () => {
+    expect(
+      getAndroidResourceIdentifier({
+        httpServerLocation: '/assets/images',
+        name: 'My Icon@2x',
+        type: 'png',
+      }),
+    ).toBe('images_myicon2x');
+  });
+
+  test('removes generated asset path prefixes', () => {
+    expect(
+      getAndroidResourceIdentifier({
+        httpServerLocation: '/assetsunstable_path/packages/app',
+        name: 'logo',
+        type: 'png',
+      }),
+    ).toBe('packages_app_logo');
+  });
+});