diff --git a/test/scripts/hexo/load_config.js b/test/scripts/hexo/load_config.js
index b105d6491d..0154cfe619 100644
--- a/test/scripts/hexo/load_config.js
+++ b/test/scripts/hexo/load_config.js
@@ -127,6 +127,16 @@ describe('Load config', () => {
         field: 'site',
         exclude: []
       });
+
+      // Test undefined
+      await writeFile(hexo.config_path, '');
+
+      await loadConfig(hexo);
+      hexo.config.external_link.should.eql({
+        enable: false,
+        field: 'site',
+        exclude: []
+      });
     } finally {
       await unlink(hexo.config_path);
     }