diff --git a/src/Tests/IntegrationTest.php b/src/Tests/IntegrationTest.php
index c6f177e..197af4b 100644
--- a/src/Tests/IntegrationTest.php
+++ b/src/Tests/IntegrationTest.php
@@ -165,6 +165,9 @@ class IntegrationTest extends WebTestBase {
       throw new SearchApiException();
     }
 
+    // Verify that search queries can be serialized.
+    serialize($index->query());
+
     // Test the "Save and edit" button.
     $index2_id = 'test_index2';
     $edit['id'] = $index2_id;