Finished migrating ll short-url helpers to TS

test/short-urls/helpers/PreviewModal.test.tsx

@@ -0,0 +1,30 @@
+import React from 'react';
+import { shallow, ShallowWrapper } from 'enzyme';
+import { ExternalLink } from 'react-external-link';
+import { Mock } from 'ts-mockery';
+import PreviewModal from '../../../src/short-urls/helpers/PreviewModal';
+import { ShortUrl } from '../../../src/short-urls/data';
+
+describe('<PreviewModal />', () => {
+  let wrapper: ShallowWrapper;
+  const shortUrl = 'https://doma.in/abc123';
+
+  beforeEach(() => {
+    wrapper = shallow(<PreviewModal shortUrl={Mock.of<ShortUrl>({ shortUrl })} isOpen={true} toggle={() => {}} />);
+  });
+  afterEach(() => wrapper.unmount());
+
+  it('shows an external link to the URL', () => {
+    const externalLink = wrapper.find(ExternalLink);
+
+    expect(externalLink).toHaveLength(1);
+    expect(externalLink.prop('href')).toEqual(shortUrl);
+  });
+
+  it('displays an image with the preview of the URL', () => {
+    const img = wrapper.find('img');
+
+    expect(img).toHaveLength(1);
+    expect(img.prop('src')).toEqual(`${shortUrl}/preview`);
+  });
+});