diff --git a/tests/phpunit/data/plugins/link-manager.json b/tests/phpunit/data/plugins/link-manager.json
new file mode 100644
index 0000000000..5752aac562
--- /dev/null
+++ b/tests/phpunit/data/plugins/link-manager.json
@@ -0,0 +1 @@
+{"name":"Link Manager","slug":"link-manager","version":"0.1-beta","author":"WordPress","author_profile":"https:\/\/profiles.wordpress.org\/nacin\/","contributors":{"nacin":{"profile":"https:\/\/profiles.wordpress.org\/nacin\/","avatar":"https:\/\/secure.gravatar.com\/avatar\/01cfe9feaafb068590891bbd1f6a7f5a?s=96&d=monsterid&r=g","display_name":"Andrew Nacin"}},"requires":"3.5","tested":"6.1.5","requires_php":false,"requires_plugins":[],"rating":90,"ratings":{"5":27,"4":3,"3":0,"2":0,"1":3},"num_ratings":33,"support_url":"https:\/\/wordpress.org\/support\/plugin\/link-manager\/","support_threads":1,"support_threads_resolved":1,"active_installs":30000,"last_updated":"2012-08-16 10:57pm GMT","added":"2012-08-16","homepage":"","download_link":"https:\/\/downloads.wordpress.org\/plugin\/link-manager.zip","upgrade_notice":[],"screenshots":[],"tags":{"blogroll":"blogroll","link-manager":"link manager","links":"links"},"versions":[],"business_model":false,"repository_url":"","commercial_support_url":"","donate_link":"","banners":[],"preview_link":"","language_packs":[]}
\ No newline at end of file
diff --git a/tests/phpunit/tests/rest-api/rest-plugins-controller.php b/tests/phpunit/tests/rest-api/rest-plugins-controller.php
index 1da20c8315..2d93c9849b 100644
--- a/tests/phpunit/tests/rest-api/rest-plugins-controller.php
+++ b/tests/phpunit/tests/rest-api/rest-plugins-controller.php
@@ -40,6 +40,13 @@ class WP_REST_Plugins_Controller_Test extends WP_Test_REST_Controller_Testcase {
 	 */
 	private static $admin;
 
+	/**
+	 * JSON decoded response from the WordPress.org plugin API.
+	 *
+	 * @var stdClass
+	 */
+	private static $plugin_api_decoded_response;
+
 	/**
 	 * Set up class test fixtures.
 	 *
@@ -67,6 +74,8 @@ class WP_REST_Plugins_Controller_Test extends WP_Test_REST_Controller_Testcase {
 		if ( is_multisite() ) {
 			grant_super_admin( self::$super_admin );
 		}
+
+		self::$plugin_api_decoded_response = json_decode( file_get_contents( DIR_TESTDATA . '/plugins/link-manager.json' ) );
 	}
 
 	/**
@@ -1017,7 +1026,12 @@ class WP_REST_Plugins_Controller_Test extends WP_Test_REST_Controller_Testcase {
 	}
 
 	/**
-	 * Sets up the plugin download to come locally instead of downloading it from .org
+	 * Sets up the plugin repository requests to use local data.
+	 *
+	 * Requests to the plugin repository are mocked to avoid external HTTP requests so
+	 * the test suite does not produce false negatives due to network failures.
+	 *
+	 * Both the plugin ZIP file and the plugin API response are mocked.
 	 *
 	 * @since 5.5.0
 	 */
@@ -1036,8 +1050,23 @@ class WP_REST_Plugins_Controller_Test extends WP_Test_REST_Controller_Testcase {
 			3
 		);
 
-		// Remove upgrade hooks which are not required for plugin installation tests
-		// and may interfere with the results due to a timeout in external HTTP requests.
+		add_filter(
+			'plugins_api',
+			function ( $bypass, $action, $args ) {
+				// Only mock the plugin_information (link-manager) request.
+				if ( 'plugin_information' !== $action || 'link-manager' !== $args->slug ) {
+					return $bypass;
+				}
+				return self::$plugin_api_decoded_response;
+			},
+			10,
+			3
+		);
+
+		/*
+		 * Remove upgrade hooks which are not required for plugin installation tests
+		 * and may interfere with the results due to a timeout in external HTTP requests.
+		 */
 		remove_action( 'upgrader_process_complete', array( 'Language_Pack_Upgrader', 'async_upgrade' ), 20 );
 		remove_action( 'upgrader_process_complete', 'wp_version_check' );
 		remove_action( 'upgrader_process_complete', 'wp_update_plugins' );