add generic caption typography component (#9283)

test/components/views/typography/Caption-test.tsx

@@ -0,0 +1,40 @@
+/*
+Copyright 2022 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import React from 'react';
+import { render } from '@testing-library/react';
+
+import { Caption } from '../../../../src/components/views/typography/Caption';
+
+describe('<Caption />', () => {
+    const defaultProps = {
+        'children': 'test',
+        'data-testid': 'test test id',
+    };
+    const getComponent = (props = {}) =>
+        (<Caption {...defaultProps} {...props} />);
+
+    it('renders plain text children', () => {
+        const { container } = render(getComponent());
+        expect({ container }).toMatchSnapshot();
+    });
+
+    it('renders react children', () => {
+        const children = <>Test <b>test but bold</b></>;
+        const { container } = render(getComponent({ children }));
+        expect({ container }).toMatchSnapshot();
+    });
+});