diff --git a/src/test/backupsites-test.js b/src/test/backupsites-test.js
index efffb50e8..a4760ef8b 100644
--- a/src/test/backupsites-test.js
+++ b/src/test/backupsites-test.js
@@ -127,6 +127,7 @@ describe('backups', function () {
 
     it('can delete all the backup sites', async function () {
         await backupSites.del(defaultBackupSite, auditSource);
+        backupSite.integrityKeyPair = {}; // keep removePrivateFields happy
         await backupSites.del(backupSite, auditSource);
 
         expect(await backups.list(1, 10)).to.eql([]);