diff --git a/module/VuFind/tests/unit-tests/src/VuFindTest/View/Helper/Root/IconTest.php b/module/VuFind/tests/unit-tests/src/VuFindTest/View/Helper/Root/IconTest.php
index c5593bfa2df..c1c77440533 100644
--- a/module/VuFind/tests/unit-tests/src/VuFindTest/View/Helper/Root/IconTest.php
+++ b/module/VuFind/tests/unit-tests/src/VuFindTest/View/Helper/Root/IconTest.php
@@ -34,6 +34,7 @@
 use Laminas\View\Helper\EscapeHtmlAttr;
 use VuFind\Escaper\Escaper;
 use VuFind\View\Helper\Root\Icon;
+use VuFindTheme\View\Helper\AssetPipeline;
 use VuFindTheme\View\Helper\ImageLink;
 
 /**
@@ -137,6 +138,7 @@ protected function getIconHelper(
         );
         $plugins = array_merge(
             [
+                'assetPipeline' => $this->createMock(AssetPipeline::class),
                 'escapeHtmlAttr' => new EscapeHtmlAttr($escaper),
             ],
             $plugins
diff --git a/module/VuFind/tests/unit-tests/src/VuFindTest/View/Helper/Root/RecordDataFormatterTest.php b/module/VuFind/tests/unit-tests/src/VuFindTest/View/Helper/Root/RecordDataFormatterTest.php
index bf40fb8ff5d..c637db39e23 100644
--- a/module/VuFind/tests/unit-tests/src/VuFindTest/View/Helper/Root/RecordDataFormatterTest.php
+++ b/module/VuFind/tests/unit-tests/src/VuFindTest/View/Helper/Root/RecordDataFormatterTest.php
@@ -89,6 +89,7 @@ protected function getViewHelpers($container): array
         });
         $record->setDbServiceManager($serviceManager);
         return [
+            'assetPipeline' => new \VuFindTheme\View\Helper\AssetPipeline(),
             'auth' => new \VuFind\View\Helper\Root\Auth(
                 $this->createMock(\VuFind\Auth\Manager::class),
                 $this->createMock(\VuFind\Auth\ILSAuthenticator::class)
diff --git a/themes/root/templates/Helpers/icons/font.phtml b/themes/root/templates/Helpers/icons/font.phtml
index 8d628755911..37de7c05794 100644
--- a/themes/root/templates/Helpers/icons/font.phtml
+++ b/themes/root/templates/Helpers/icons/font.phtml
@@ -1,5 +1,7 @@
 <?php
-    $this->assetPipeline()->appendStylesheet($this->src);
+    if ($this->src) {
+        $this->assetPipeline()->appendStylesheet($this->src);
+    }
     $className = trim('icon icon--font ' . $this->icon . ' ' . ($this->extra['class'] ?? ''));
 ?>
 <span class="<?=$this->escapeHtmlAttr($className) ?>"<?=$this->attrs ?> role="img" aria-hidden="true"></span>