use stable reference for active tab in tabbedView (#9145)

test/components/structures/TabbedView-test.tsx

@@ -0,0 +1,133 @@
+/*
+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 { fireEvent, render } from "@testing-library/react";
+import { act } from 'react-dom/test-utils';
+
+import TabbedView, { Tab, TabLocation } from "../../../src/components/structures/TabbedView";
+
+describe('<TabbedView />', () => {
+    const generalTab = new Tab(
+        'GENERAL',
+        'General',
+        'general',
+        <div>general</div>,
+    );
+    const labsTab = new Tab(
+        'LABS',
+        'Labs',
+        'labs',
+        <div>labs</div>,
+    );
+    const securityTab = new Tab(
+        'SECURITY',
+        'Security',
+        'security',
+        <div>security</div>,
+    );
+    const defaultProps = {
+        tabLocation: TabLocation.LEFT,
+        tabs: [generalTab, labsTab, securityTab],
+    };
+    const getComponent = (props = {}): React.ReactElement => <TabbedView {...defaultProps} {...props} />;
+
+    const getTabTestId = (tab: Tab): string => `settings-tab-${tab.id}`;
+    const getActiveTab = (container: HTMLElement): Element | undefined =>
+        container.getElementsByClassName('mx_TabbedView_tabLabel_active')[0];
+    const getActiveTabBody = (container: HTMLElement): Element | undefined =>
+        container.getElementsByClassName('mx_TabbedView_tabPanel')[0];
+
+    it('renders tabs', () => {
+        const { container } = render(getComponent());
+        expect(container).toMatchSnapshot();
+    });
+
+    it('renders first tab as active tab when no initialTabId', () => {
+        const { container } = render(getComponent());
+        expect(getActiveTab(container).textContent).toEqual(generalTab.label);
+        expect(getActiveTabBody(container).textContent).toEqual('general');
+    });
+
+    it('renders first tab as active tab when initialTabId is not valid', () => {
+        const { container } = render(getComponent({ initialTabId: 'bad-tab-id' }));
+        expect(getActiveTab(container).textContent).toEqual(generalTab.label);
+        expect(getActiveTabBody(container).textContent).toEqual('general');
+    });
+
+    it('renders initialTabId tab as active when valid', () => {
+        const { container } = render(getComponent({ initialTabId: securityTab.id }));
+        expect(getActiveTab(container).textContent).toEqual(securityTab.label);
+        expect(getActiveTabBody(container).textContent).toEqual('security');
+    });
+
+    it('renders without error when there are no tabs', () => {
+        const { container } = render(getComponent({ tabs: [] }));
+        expect(container).toMatchSnapshot();
+    });
+
+    it('sets active tab on tab click', () => {
+        const { container, getByTestId } = render(getComponent());
+
+        act(() => {
+            fireEvent.click(getByTestId(getTabTestId(securityTab)));
+        });
+
+        expect(getActiveTab(container).textContent).toEqual(securityTab.label);
+        expect(getActiveTabBody(container).textContent).toEqual('security');
+    });
+
+    it('calls onchange on on tab click', () => {
+        const onChange = jest.fn();
+        const { getByTestId } = render(getComponent({ onChange }));
+
+        act(() => {
+            fireEvent.click(getByTestId(getTabTestId(securityTab)));
+        });
+
+        expect(onChange).toHaveBeenCalledWith(securityTab.id);
+    });
+
+    it('keeps same tab active when order of tabs changes', () => {
+        // start with middle tab active
+        const { container, rerender } = render(getComponent({ initialTabId: labsTab.id }));
+
+        expect(getActiveTab(container).textContent).toEqual(labsTab.label);
+
+        rerender(getComponent({ tabs: [labsTab, generalTab, securityTab] }));
+
+        // labs tab still active
+        expect(getActiveTab(container).textContent).toEqual(labsTab.label);
+    });
+
+    it('does not reactivate inititalTabId on rerender', () => {
+        const { container, getByTestId, rerender } = render(getComponent());
+
+        expect(getActiveTab(container).textContent).toEqual(generalTab.label);
+
+        // make security tab active
+        act(() => {
+            fireEvent.click(getByTestId(getTabTestId(securityTab)));
+        });
+        expect(getActiveTab(container).textContent).toEqual(securityTab.label);
+
+        // rerender with new tab location
+        rerender(getComponent({ tabLocation: TabLocation.TOP }));
+
+        // still security tab
+        expect(getActiveTab(container).textContent).toEqual(securityTab.label);
+    });
+});