add unit tests

tests/components/Label.test.tsx

@@ -0,0 +1,25 @@
+import { render, screen } from '@testing-library/react';
+import { describe, expect, it } from 'vitest';
+import { Label } from '../../src/components/Label';
+
+describe('Label', () => {
+    it('uses default and variant-specific tags/classes', () => {
+        const { rerender } = render(<Label>Body</Label>);
+        expect(screen.getByText('Body').tagName).toBe('P');
+        expect(screen.getByText('Body')).toHaveClass('ui-body-primary');
+
+        rerender(<Label variant="h1">Title</Label>);
+        expect(screen.getByText('Title').tagName).toBe('H1');
+        expect(screen.getByText('Title')).toHaveClass('ui-title');
+
+        rerender(<Label variant="h4">Section</Label>);
+        expect(screen.getByText('Section').tagName).toBe('H3');
+
+        rerender(
+            <Label variant="h2" as="span">
+                Custom
+            </Label>,
+        );
+        expect(screen.getByText('Custom').tagName).toBe('SPAN');
+    });
+});