test: switch line tests to react testing library (#1361)

packages/react/src/components/Line/index.test.tsx

@@ -0,0 +1,16 @@
+import React from 'react';
+import { render } from '@testing-library/react';
+import Line from './index';
+import axe from '../../axe';
+
+test('passes classNames through', () => {
+  const { container } = render(<Line className="baz" />);
+  expect(container.firstChild).toHaveClass('Line', 'baz');
+});
+
+test('should return no axe violations', async () => {
+  const { container } = render(<Line />);
+
+  const results = await axe(container);
+  expect(results).toHaveNoViolations();
+});