diff --git a/frontend/src/lib/activity/ChronikFilterPills.svelte.test.ts b/frontend/src/lib/activity/ChronikFilterPills.svelte.test.ts
new file mode 100644
index 00000000..c04fdf4b
--- /dev/null
+++ b/frontend/src/lib/activity/ChronikFilterPills.svelte.test.ts
@@ -0,0 +1,53 @@
+import { describe, it, expect, vi, afterEach } from 'vitest';
+import { cleanup, render } from 'vitest-browser-svelte';
+import { page } from 'vitest/browser';
+import ChronikFilterPills from './ChronikFilterPills.svelte';
+
+afterEach(cleanup);
+
+describe('ChronikFilterPills', () => {
+	it('renders the radiogroup with the label', async () => {
+		render(ChronikFilterPills, { props: { value: 'alle' as const, onChange: () => {} } });
+
+		await expect
+			.element(page.getByRole('radiogroup', { name: /aktivitäten filtern/i }))
+			.toBeVisible();
+	});
+
+	it('renders all five filter pills', async () => {
+		render(ChronikFilterPills, { props: { value: 'alle' as const, onChange: () => {} } });
+
+		const radios = document.querySelectorAll('[role="radio"]');
+		expect(radios.length).toBe(5);
+	});
+
+	it('marks the active filter as aria-checked=true', async () => {
+		render(ChronikFilterPills, { props: { value: 'fuer-dich' as const, onChange: () => {} } });
+
+		const active = document.querySelector('[data-filter-value="fuer-dich"]') as HTMLElement;
+		expect(active.getAttribute('aria-checked')).toBe('true');
+	});
+
+	it('sets tabindex=0 on the active pill and -1 on others', async () => {
+		render(ChronikFilterPills, { props: { value: 'kommentare' as const, onChange: () => {} } });
+
+		const active = document.querySelector('[data-filter-value="kommentare"]') as HTMLElement;
+		const others = Array.from(document.querySelectorAll('[role="radio"]')).filter(
+			(el) => el !== active
+		) as HTMLElement[];
+		expect(active.tabIndex).toBe(0);
+		others.forEach((el) => expect(el.tabIndex).toBe(-1));
+	});
+
+	it('calls onChange with the new filter value when clicked', async () => {
+		const onChange = vi.fn();
+		render(ChronikFilterPills, { props: { value: 'alle' as const, onChange } });
+
+		const transcription = document.querySelector(
+			'[data-filter-value="transkription"]'
+		) as HTMLElement;
+		transcription.click();
+
+		expect(onChange).toHaveBeenCalledWith('transkription');
+	});
+});