Added snippets for enabling test ads

PiperOrigin-RevId: 788570507

Author: malandr2

samples/HelloWorld/Snippets/RequestConfigurationSnippets.cs

@@ -0,0 +1,32 @@
+using UnityEngine;
+using GoogleMobileAds.Api;
+using System.Collections.Generic;
+
+namespace GoogleMobileAds.Snippets
+{
+    /// <summary>
+    /// Code snippets used for the developer guides.
+    /// </summary>
+    internal class RequestConfigurationSnippets
+    {
+        // Replace with your own test device ID.
+        private const string TEST_DEVICE_ID = "2077ef9a63d2b398840261c8221a0c9b";
+
+        private void SetTestDeviceIds()
+        {
+            // [START set_test_device_ids]
+            List<string> testDeviceIds = new List<string>();
+            testDeviceIds.Add(TEST_DEVICE_ID);
+
+            RequestConfiguration requestConfiguration = new RequestConfiguration
+            {
+                TestDeviceIds = testDeviceIds
+            };
+            // [END set_test_device_ids]
+
+            // [START set_request_configuration]
+            MobileAds.SetRequestConfiguration(requestConfiguration);
+            // [END set_request_configuration]
+        }
+    }
+}