diff --git a/frontend/src/lib/document/FileSwitcherStrip.svelte.test.ts b/frontend/src/lib/document/FileSwitcherStrip.svelte.test.ts
index 3defb75a..7490573c 100644
--- a/frontend/src/lib/document/FileSwitcherStrip.svelte.test.ts
+++ b/frontend/src/lib/document/FileSwitcherStrip.svelte.test.ts
@@ -120,36 +120,43 @@ describe('FileSwitcherStrip', () => {
 		expect(announcer?.textContent).toContain('Ein Brief.pdf');
 	});
 
-	it('clicking prev button does not throw with no scroll target available', async () => {
+	it('prev button on a single-file strip is a no-op (active chip stays)', async () => {
+		const onSelect = vi.fn();
 		render(FileSwitcherStrip, {
 			props: {
 				files: [makeEntry('f1', 'A.pdf')],
 				activeId: 'f1',
-				onSelect: () => {},
+				onSelect,
 				onRemove: () => {}
 			}
 		});
 
-		const prevBtn = Array.from(document.querySelectorAll('button')).find((b) =>
-			/vorherige|prev/i.test(b.getAttribute('aria-label') ?? '')
-		) as HTMLButtonElement;
-		expect(() => prevBtn.click()).not.toThrow();
+		await page.getByRole('button', { name: /vorherige datei/i }).click();
+
+		// The active chip is still f1 and onSelect was not invoked with a different id.
+		expect(document.querySelector('[data-chip-id="f1"]')?.getAttribute('aria-current')).toBe(
+			'true'
+		);
+		expect(onSelect).not.toHaveBeenCalled();
 	});
 
-	it('clicking next button does not throw', async () => {
+	it('next button on a single-file strip is a no-op (active chip stays)', async () => {
+		const onSelect = vi.fn();
 		render(FileSwitcherStrip, {
 			props: {
 				files: [makeEntry('f1', 'A.pdf')],
 				activeId: 'f1',
-				onSelect: () => {},
+				onSelect,
 				onRemove: () => {}
 			}
 		});
 
-		const nextBtn = Array.from(document.querySelectorAll('button')).find((b) =>
-			/nächste|next/i.test(b.getAttribute('aria-label') ?? '')
-		) as HTMLButtonElement;
-		expect(() => nextBtn.click()).not.toThrow();
+		await page.getByRole('button', { name: /nächste datei/i }).click();
+
+		expect(document.querySelector('[data-chip-id="f1"]')?.getAttribute('aria-current')).toBe(
+			'true'
+		);
+		expect(onSelect).not.toHaveBeenCalled();
 	});
 
 	it('navigates with ArrowRight key on focused chip', async () => {
@@ -166,8 +173,9 @@ describe('FileSwitcherStrip', () => {
 		f1.focus();
 		f1.dispatchEvent(new KeyboardEvent('keydown', { key: 'ArrowRight', bubbles: true }));
 
-		await new Promise((r) => setTimeout(r, 30));
-		expect(document.activeElement?.getAttribute('data-chip-id')).toBe('f2');
+		await vi.waitFor(() => {
+			expect(document.activeElement?.getAttribute('data-chip-id')).toBe('f2');
+		});
 	});
 
 	it('navigates with ArrowLeft key on focused chip (wraps around)', async () => {
@@ -184,9 +192,10 @@ describe('FileSwitcherStrip', () => {
 		f1.focus();
 		f1.dispatchEvent(new KeyboardEvent('keydown', { key: 'ArrowLeft', bubbles: true }));
 
-		await new Promise((r) => setTimeout(r, 30));
-		// ArrowLeft from index 0 wraps to last (f2)
-		expect(document.activeElement?.getAttribute('data-chip-id')).toBe('f2');
+		await vi.waitFor(() => {
+			// ArrowLeft from index 0 wraps to last (f2).
+			expect(document.activeElement?.getAttribute('data-chip-id')).toBe('f2');
+		});
 	});
 
 	it('ArrowDown is treated as ArrowRight (vertical key alias)', async () => {
@@ -203,7 +212,8 @@ describe('FileSwitcherStrip', () => {
 		f1.focus();
 		f1.dispatchEvent(new KeyboardEvent('keydown', { key: 'ArrowDown', bubbles: true }));
 
-		await new Promise((r) => setTimeout(r, 30));
-		expect(document.activeElement?.getAttribute('data-chip-id')).toBe('f2');
+		await vi.waitFor(() => {
+			expect(document.activeElement?.getAttribute('data-chip-id')).toBe('f2');
+		});
 	});
 });