diff --git a/lib/google/curlio.php b/lib/google/curlio.php
index 72e7d2fb859..ed2ceb54e6d 100644
--- a/lib/google/curlio.php
+++ b/lib/google/curlio.php
@@ -124,7 +124,7 @@ class moodle_google_curlio extends Google_IO_Curl {
         $curlerrornum = $curl->get_errno();
         $curlerror = $curl->error;
 
-        if ($respdata != CURLE_OK) {
+        if ($curlerrornum != CURLE_OK) {
             throw new Google_IO_Exception($curlerror);
         }
 
diff --git a/lib/tests/googlelib_test.php b/lib/tests/googlelib_test.php
new file mode 100644
index 00000000000..4489fcf64cc
--- /dev/null
+++ b/lib/tests/googlelib_test.php
@@ -0,0 +1,40 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * Tests for google library
+ *
+ * @package    core
+ * @copyright  2021 Marina Glancy
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class core_googlelib_testcase extends advanced_testcase {
+
+    public function test_invalid_google_api_key() {
+        global $CFG;
+        require_once($CFG->libdir . '/google/lib.php');
+        $client = get_google_client();
+        $client->setDeveloperKey('invalid');
+        $client->setScopes(array(Google_Service_YouTube::YOUTUBE_READONLY));
+        $service = new Google_Service_YouTube($client);
+        try {
+            $service->videoCategories->listVideoCategories('snippet', ['regionCode' => 'us']);
+            $this->fail('Exception expected');
+        } catch (Google_Service_Exception $e) {
+            $this->assertMatchesRegularExpression('/API key not valid/', $e->getMessage());
+        }
+    }
+}