feat: add test app universal link support (MetaMask#27811)

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## **Description**

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This PR adds test app universal link support to facilitate testing
non-production builds

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## **Related issues**

Fixes:

## **Manual testing steps**

```gherkin
Feature: my feature name

  Scenario: user [verb for user action]
    Given [describe expected initial app state]

    When user [verb for user action]
    Then [describe expected outcome]
```

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## **Pre-merge author checklist**

- [ ] I've followed [MetaMask Contributor
Docs](https://github.com/MetaMask/contributor-docs) and [MetaMask Mobile
Coding
Standards](https://github.com/MetaMask/metamask-mobile/blob/main/.github/guidelines/CODING_GUIDELINES.md).
- [ ] I've completed the PR template to the best of my ability
- [ ] I've included tests if applicable
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- [ ] I've manually tested the PR (e.g. pull and build branch, run the
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as recordings and or screenshots.


<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> **Low Risk**
> Low risk: this only broadens the set of recognized universal-link
hostnames and updates iOS associated-domain/Branch domain allowlists; no
auth, signing, or transaction logic changes.
> 
> **Overview**
> Adds support for additional **test app** universal-link domains
(including an alternate host) so non-production builds can open MetaMask
via `https://metamask.test-app.link` and
`https://metamask-alternate.test-app.link`.
> 
> Updates universal-link validation/host allowlists in
`handleUniversalLink` and deeplink utils, extends unit tests
accordingly, and fixes iOS `Info.plist`/entitlements domain lists to use
the `test-app.link` hostnames.
> 
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
2f29a9a. This will update automatically
on new commits. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

Author: baptiste-marchand

app/core/AppConstants.ts

@@ -96,6 +96,8 @@ export default {
   },
   MM_UNIVERSAL_LINK_HOST: 'metamask.app.link',
   MM_UNIVERSAL_LINK_HOST_ALTERNATE: 'metamask-alternate.app.link',
+  MM_UNIVERSAL_LINK_TEST_APP_HOST: 'metamask.test-app.link',
+  MM_UNIVERSAL_LINK_TEST_APP_HOST_ALTERNATE: 'metamask-alternate.test-app.link',
   MM_IO_UNIVERSAL_LINK_HOST: 'link.metamask.io',
   MM_IO_UNIVERSAL_LINK_TEST_HOST: 'link-test.metamask.io',
   MM_DEEP_ITMS_APP_LINK: 'https://metamask.app.link/skAH3BaF99',

app/core/DeeplinkManager/handlers/legacy/handleUniversalLink.ts

@@ -57,6 +57,8 @@ import Logger from '../../../../util/Logger';
 const {
   MM_UNIVERSAL_LINK_HOST,
   MM_UNIVERSAL_LINK_HOST_ALTERNATE,
+  MM_UNIVERSAL_LINK_TEST_APP_HOST,
+  MM_UNIVERSAL_LINK_TEST_APP_HOST_ALTERNATE,
   MM_IO_UNIVERSAL_LINK_HOST,
   MM_IO_UNIVERSAL_LINK_TEST_HOST,
 } = AppConstants;
@@ -221,6 +223,8 @@ async function handleUniversalLink({
   const isSupportedDomain =
     urlObj.hostname === MM_UNIVERSAL_LINK_HOST ||
     urlObj.hostname === MM_UNIVERSAL_LINK_HOST_ALTERNATE ||
+    urlObj.hostname === MM_UNIVERSAL_LINK_TEST_APP_HOST ||
+    urlObj.hostname === MM_UNIVERSAL_LINK_TEST_APP_HOST_ALTERNATE ||
     urlObj.hostname === MM_IO_UNIVERSAL_LINK_HOST ||
     urlObj.hostname === MM_IO_UNIVERSAL_LINK_TEST_HOST;
 

app/core/DeeplinkManager/util/deeplinks/index.test.ts

@@ -15,6 +15,11 @@ describe('deeplinks utils', () => {
       expect(
         isMetaMaskUniversalLink('https://metamask.test-app.link/home'),
       ).toBe(true);
+      expect(
+        isMetaMaskUniversalLink(
+          'https://metamask-alternate.test-app.link/swap',
+        ),
+      ).toBe(true);
       expect(
         isMetaMaskUniversalLink('https://link-test.metamask.io/send'),
       ).toBe(true);
@@ -80,6 +85,9 @@ describe('deeplinks utils', () => {
       expect(isInternalDeepLink('https://metamask.test-app.link/home')).toBe(
         true,
       );
+      expect(
+        isInternalDeepLink('https://metamask-alternate.test-app.link/dapp/x'),
+      ).toBe(true);
     });
 
     it('does not identify external URLs as internal', () => {

app/core/DeeplinkManager/util/deeplinks/index.ts

@@ -3,19 +3,21 @@ import AppConstants from '../../../AppConstants';
 const {
   MM_UNIVERSAL_LINK_HOST,
   MM_UNIVERSAL_LINK_HOST_ALTERNATE,
+  MM_UNIVERSAL_LINK_TEST_APP_HOST,
+  MM_UNIVERSAL_LINK_TEST_APP_HOST_ALTERNATE,
   MM_IO_UNIVERSAL_LINK_HOST,
   MM_IO_UNIVERSAL_LINK_TEST_HOST,
 } = AppConstants;
 
-const METAMASK_HOSTS = [
+const METAMASK_HOSTS: readonly string[] = [
   ...new Set(
     [
-      MM_UNIVERSAL_LINK_HOST || 'link.metamask.io',
-      MM_UNIVERSAL_LINK_HOST_ALTERNATE || 'metamask-alternate.app.link',
-      MM_IO_UNIVERSAL_LINK_HOST || 'link.metamask.io',
-      MM_IO_UNIVERSAL_LINK_TEST_HOST || 'link-test.metamask.io',
-      'metamask.app.link',
-      'metamask.test-app.link',
+      MM_UNIVERSAL_LINK_HOST,
+      MM_UNIVERSAL_LINK_HOST_ALTERNATE,
+      MM_IO_UNIVERSAL_LINK_HOST,
+      MM_IO_UNIVERSAL_LINK_TEST_HOST,
+      MM_UNIVERSAL_LINK_TEST_APP_HOST,
+      MM_UNIVERSAL_LINK_TEST_APP_HOST_ALTERNATE,
     ].filter(Boolean),
   ),
 ];

ios/MetaMask/Info.plist

@@ -138,8 +138,8 @@
 		<string>link.metamask.io</string>
 		<string>link-test.metamask.io</string>
 		<string>metamask-alternate.app.link</string>
-		<string>metamask.test.app.link</string>
-		<string>metamask-alternate.test.app.link</string>
+		<string>metamask.test-app.link</string>
+		<string>metamask-alternate.test-app.link</string>
 	</array>
 	<key>fox_code</key>
 	<string>$(MM_FOX_CODE)</string>

ios/MetaMask/MetaMask-Flask-Info.plist

@@ -129,8 +129,8 @@
 		<string>link.metamask.io</string>
 		<string>link-test.metamask.io</string>
 		<string>metamask-alternate.app.link</string>
-		<string>metamask.test.app.link</string>
-		<string>metamask-alternate.test.app.link</string>
+		<string>metamask.test-app.link</string>
+		<string>metamask-alternate.test-app.link</string>
 	</array>
 	<key>fox_code</key>
 	<string>$(MM_FOX_CODE)</string>

ios/MetaMask/MetaMask.entitlements

@@ -15,6 +15,8 @@
 		<string>applinks:metamask-alternate.app.link</string>
 		<string>applinks:link.metamask.io</string>
 		<string>applinks:link-test.metamask.io</string>
+		<string>applinks:metamask.test-app.link</string>
+		<string>applinks:metamask-alternate.test-app.link</string>
 		<string>webcredentials:link.metamask.io</string>
 	</array>
 	<key>com.apple.developer.in-app-payments</key>

ios/MetaMask/MetaMaskDebug.entitlements

@@ -15,6 +15,8 @@
 		<string>applinks:metamask-alternate.app.link</string>
 		<string>applinks:link.metamask.io</string>
 		<string>applinks:link-test.metamask.io</string>
+		<string>applinks:metamask.test-app.link</string>
+		<string>applinks:metamask-alternate.test-app.link</string>
 		<string>webcredentials:link.metamask.io</string>
 	</array>
 	<key>com.apple.developer.in-app-payments</key>