Test multiple markdown extensions (#1886)

This commit adds multiple unit jest tests for components and removes e2e tests. 

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

Signed-off-by: Philip Molares <philip.molares@udo.edu>

Co-authored-by: Philip Molares <philip.molares@udo.edu>

src/components/markdown-renderer/markdown-extension/graphviz/graphviz-markdown-extension.test.tsx

@@ -0,0 +1,42 @@
+/*
+ * SPDX-FileCopyrightText: 2022 The HedgeDoc developers (see AUTHORS file)
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+import { render } from '@testing-library/react'
+import { TestMarkdownRenderer } from '../../test-utils/test-markdown-renderer'
+import React from 'react'
+import { mockI18n } from '../../test-utils/mock-i18n'
+import { GraphvizMarkdownExtension } from './graphviz-markdown-extension'
+import * as GraphvizFrameModule from '../graphviz/graphviz-frame'
+import type { CodeProps } from '../../replace-components/code-block-component-replacer'
+
+describe('PlantUML markdown extensions', () => {
+  beforeAll(async () => {
+    jest.spyOn(GraphvizFrameModule, 'GraphvizFrame').mockImplementation((({ code }) => {
+      return (
+        <span>
+          this is a mock for graphviz frame
+          <code>{code}</code>
+        </span>
+      )
+    }) as React.FC<CodeProps>)
+    await mockI18n()
+  })
+
+  afterAll(() => {
+    jest.resetModules()
+    jest.restoreAllMocks()
+  })
+
+  it('renders a plantuml codeblock', () => {
+    const view = render(
+      <TestMarkdownRenderer
+        extensions={[new GraphvizMarkdownExtension()]}
+        content={'```graphviz\ngraph {\na -- b\n}\n```'}
+      />
+    )
+    expect(view.container).toMatchSnapshot()
+  })
+})