Replace JavaScript Testing Framework from Mocha to Jest (#5412)

app/javascript/mastodon/components/__tests__/avatar_overlay-test.js

@@ -0,0 +1,29 @@
+import React from 'react';
+import renderer from 'react-test-renderer';
+import { fromJS } from 'immutable';
+import AvatarOverlay from '../avatar_overlay';
+
+describe('<AvatarOverlay', () => {
+  const account = fromJS({
+    username: 'alice',
+    acct: 'alice',
+    display_name: 'Alice',
+    avatar: '/animated/alice.gif',
+    avatar_static: '/static/alice.jpg',
+  });
+
+  const friend = fromJS({
+    username: 'eve',
+    acct: 'eve@blackhat.lair',
+    display_name: 'Evelyn',
+    avatar: '/animated/eve.gif',
+    avatar_static: '/static/eve.jpg',
+  });
+
+  it('renders a overlay avatar', () => {
+    const component = renderer.create(<AvatarOverlay account={account} friend={friend} />);
+    const tree      = component.toJSON();
+
+    expect(tree).toMatchSnapshot();
+  });
+});