feat(extensions): Introduce app extensions

Signed-off-by: Tilman Vatteroth <git@tilmanvatteroth.de>

src/extensions/extra-integrations/csv/csv-table.test.tsx

@@ -0,0 +1,25 @@
+/*
+ * SPDX-FileCopyrightText: 2022 The HedgeDoc developers (see AUTHORS file)
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+import { render } from '@testing-library/react'
+import { CsvTable } from './csv-table'
+
+describe('CSV Table', () => {
+  it('renders correctly with header', () => {
+    const view = render(<CsvTable code={'a;b;c\nd;e;f'} delimiter={';'} showHeader={true} />)
+    expect(view.container).toMatchSnapshot()
+  })
+
+  it('renders correctly without header', () => {
+    const view = render(<CsvTable code={'a;b;c\nd;e;f'} delimiter={';'} showHeader={false} />)
+    expect(view.container).toMatchSnapshot()
+  })
+
+  it('renders correctly without code', () => {
+    const view = render(<CsvTable code={''} delimiter={';'} showHeader={false} />)
+    expect(view.container).toMatchSnapshot()
+  })
+})