web/vitest.setup.ts

@@ -37,6 +37,14 @@ if (typeof window !== 'undefined') {
   Object.defineProperty(window, 'sessionStorage', { configurable: true, value: memSession });
 }
 
+// jsdom doesn't implement Element.prototype.scrollIntoView. Components that
+// call it (queue auto-scroll to the now-playing row, the alphabetical rail)
+// would throw an unhandled TypeError in tests — which fails the run even when
+// every assertion passes. No-op it; tests never assert on scroll position.
+if (typeof Element !== 'undefined' && !Element.prototype.scrollIntoView) {
+  Element.prototype.scrollIntoView = () => {};
+}
+
 // W-T3 moved toast rendering out of per-page markup into a single
 // <ToastHost /> mounted in +layout.svelte. Tests render individual pages
 // without the layout, so we mount ToastHost here so `pushToast()` calls