Added test for get_browser_nodes

tests/test_api_get_browse_nodes.py

@@ -0,0 +1,15 @@
+import unittest
+from unittest import mock
+
+from amazon_paapi import AmazonApi, models
+from amazon_paapi.helpers import requests
+
+
+class TestGetBrowseNodes(unittest.TestCase):
+    @mock.patch.object(requests, "get_browse_nodes_response")
+    def test_search_items(self, mocked_get_browse_nodes_response):
+        mocked_response = []
+        mocked_get_browse_nodes_response.return_value = mocked_response
+        amazon = AmazonApi("key", "secret", "tag", "ES")
+        response = amazon.get_browse_nodes(['ABCDEFGHIJ'])
+        self.assertTrue(isinstance(response, list))