Rename JSX files with proper .jsx extension (#23733)

app/javascript/mastodon/components/__tests__/avatar-test.jsx

@@ -0,0 +1,36 @@
+import React from 'react';
+import renderer from 'react-test-renderer';
+import { fromJS } from 'immutable';
+import Avatar from '../avatar';
+
+describe('<Avatar />', () => {
+  const account = fromJS({
+    username: 'alice',
+    acct: 'alice',
+    display_name: 'Alice',
+    avatar: '/animated/alice.gif',
+    avatar_static: '/static/alice.jpg',
+  });
+
+  const size     = 100;
+
+  describe('Autoplay', () => {
+    it('renders a animated avatar', () => {
+      const component = renderer.create(<Avatar account={account} animate size={size} />);
+      const tree      = component.toJSON();
+
+      expect(tree).toMatchSnapshot();
+    });
+  });
+
+  describe('Still', () => {
+    it('renders a still avatar', () => {
+      const component = renderer.create(<Avatar account={account} size={size} />);
+      const tree      = component.toJSON();
+
+      expect(tree).toMatchSnapshot();
+    });
+  });
+
+  // TODO add autoplay test if possible
+});