test(*): migrate from enzyme to react-testing-library

Author: christopherthielen

Diff for: jest.setup.js

@@ -1,4 +1,19 @@
-var Enzyme = require('enzyme');
-var Adapter = require('enzyme-adapter-react-16');
+// There should be a single listener which simply prints to the
+// console. We will wrap that listener in our own listener.
+const listeners = window._virtualConsole.listeners('jsdomError');
+const originalListener = listeners && listeners[0];
 
-Enzyme.configure({ adapter: new Adapter() });
+window._virtualConsole.removeAllListeners('jsdomError');
+
+// Add a new listener to swallow JSDOM errors that originate from clicks on anchor tags.
+window._virtualConsole.addListener('jsdomError', (error) => {
+  if (
+    error.type !== 'not implemented' &&
+    error.message !== 'Not implemented: navigation (except hash changes)' &&
+    originalListener
+  ) {
+    originalListener(error);
+  }
+
+  // swallow error
+});

Diff for: package.json

@@ -47,11 +47,12 @@
     "prop-types": "^15.6.1"
   },
   "peerDependencies": {
-    "react": "^16.8.0"
+    "react": ">=16.8.0"
   },
   "devDependencies": {
+    "@testing-library/jest-dom": "^5.14.1",
+    "@testing-library/react": "^12.0.0",
     "@types/classnames": "^2.3.1",
-    "@types/enzyme": "^3.10.9",
     "@types/jest": "^26.0.24",
     "@types/lodash": "^4.14.171",
     "@types/prop-types": "15.7.4",
@@ -66,8 +67,6 @@
     "canvas": "2.8.0",
     "chalk": "^4.0.0",
     "cross-env": "^7.0.3",
-    "enzyme": "^3.4.1",
-    "enzyme-adapter-react-16": "^1.15.5",
     "husky": "^4.3.6",
     "jest": "27.0.6",
     "prettier": "^2.3.2",
@@ -93,6 +92,7 @@
     "transform": {
       ".(ts|tsx)": "ts-jest"
     },
+    "testEnvironment": "jsdom",
     "moduleFileExtensions": [
       "js",
       "json",

Diff for: src/__tests__/util.tsx

@@ -1,6 +1,6 @@
 import * as React from 'react';
 import { TransitionOptions, RawParams, StateOrName, TransitionPromise, memoryLocationPlugin } from '@uirouter/core';
-import { mount } from 'enzyme';
+import { render } from '@testing-library/react';
 import { act } from 'react-dom/test-utils';
 import { UIRouterReact } from '../core';
 import { servicesPlugin, UIRouter } from '../index';
@@ -11,18 +11,19 @@ export const makeTestRouter = (states: ReactStateDeclaration[]) => {
   router.plugin(servicesPlugin);
   router.plugin(memoryLocationPlugin);
   router.locationConfig.html5Mode = () => true;
-  states.forEach(state => router.stateRegistry.register(state));
+  states.forEach((state) => router.stateRegistry.register(state));
 
-  const mountInRouter: typeof mount = (children, opts) => {
-    const WrapperComponent = props => {
+  const mountInRouter: typeof render = (children, opts?) => {
+    const WrapperComponent = (props) => {
       const cloned = React.cloneElement(children, props);
       return <UIRouter router={router}>{cloned}</UIRouter>;
     };
-    return mount(<WrapperComponent />, opts);
+
+    return render(<WrapperComponent />, opts) as any;
   };
 
-  const routerGo = function(to: StateOrName, params?: RawParams, options?: TransitionOptions) {
-    return (act(() => router.stateService.go(to, params, options)) as any) as TransitionPromise;
+  const routerGo = function (to: StateOrName, params?: RawParams, options?: TransitionOptions): TransitionPromise {
+    return act(() => router.stateService.go(to, params, options) as any) as any;
   };
 
   return { router, routerGo, mountInRouter };

Diff for: src/components/__tests__/UIRouter.test.tsx

@@ -1,6 +1,6 @@
+import { render } from '@testing-library/react';
 import * as React from 'react';
 import * as PropTypes from 'prop-types';
-import { mount } from 'enzyme';
 import { UIRouterContext, UIRouter } from '../UIRouter';
 import { UIRouterReact } from '../../core';
 import { memoryLocationPlugin } from '../../index';
@@ -19,7 +19,7 @@ describe('<UIRouter>', () => {
   it('throws an error if no plugin or router instance is passed via prop', () => {
     muteConsoleErrors();
     expect(() =>
-      mount(
+      render(
         <UIRouter>
           <Child />
         </UIRouter>
@@ -28,45 +28,49 @@ describe('<UIRouter>', () => {
   });
 
   it('creates a router instance', () => {
-    const wrapper = mount(
+    const rendered = render(
       <UIRouter plugins={[memoryLocationPlugin]} states={[]}>
-        <UIRouterContext.Consumer>{router => <Child router={router} />}</UIRouterContext.Consumer>
+        <UIRouterContext.Consumer>
+          {(router) => <span>{router === undefined ? 'yes' : 'no'}</span>}
+        </UIRouterContext.Consumer>
       </UIRouter>
     );
-    expect(wrapper.find(Child).props().router).toBeDefined();
+    expect(rendered.asFragment().textContent).toBe('no');
   });
 
   it('accepts an instance via prop', () => {
     const router = new UIRouterReact();
     router.plugin(memoryLocationPlugin);
-    const wrapper = mount(
+    const rendered = render(
       <UIRouter router={router}>
-        <UIRouterContext.Consumer>{router => <Child router={router} />}</UIRouterContext.Consumer>
+        <UIRouterContext.Consumer>
+          {(instance) => <span>{instance === router ? 'yes' : 'no'}</span>}
+        </UIRouterContext.Consumer>
       </UIRouter>
     );
-    expect(wrapper.find(Child).props().router).toBe(router);
+    expect(rendered.asFragment().textContent).toBe('yes');
   });
 
   it('starts the router', () => {
     const router = new UIRouterReact();
     router.plugin(memoryLocationPlugin);
-    spyOn(router, 'start');
-    mount(
+    const spy = jest.spyOn(router, 'start');
+    render(
       <UIRouter router={router}>
-        <UIRouterContext.Consumer>{router => <Child router={router} />}</UIRouterContext.Consumer>
+        <UIRouterContext.Consumer>{(router) => <Child router={router} />}</UIRouterContext.Consumer>
       </UIRouter>
     );
-    expect(router.start).toHaveBeenCalledTimes(1);
+    expect(spy).toHaveBeenCalledTimes(1);
   });
 
   describe('<UIRouterCosumer>', () => {
     it('passes down the router instance', () => {
       let router;
 
-      mount(
+      render(
         <UIRouter plugins={[memoryLocationPlugin]}>
           <UIRouterContext.Consumer>
-            {_router => {
+            {(_router) => {
               router = _router;
               return null;
             }}
@@ -80,10 +84,10 @@ describe('<UIRouter>', () => {
     it('passes down the correct router instance when passed via props', () => {
       const router = new UIRouterReact();
       router.plugin(memoryLocationPlugin);
-      mount(
+      render(
         <UIRouter router={router}>
           <UIRouterContext.Consumer>
-            {_router => {
+            {(_router) => {
               expect(_router).toBe(router);
               return null;
             }}

Diff for: src/components/__tests__/UISref.test.tsx

@@ -1,3 +1,4 @@
+import { fireEvent } from '@testing-library/react';
 import * as React from 'react';
 import { UISref, UIView } from '../../components';
 import { UISrefActiveContext } from '../UISrefActive';
@@ -21,22 +22,25 @@ const states = [
 ];
 
 describe('<UISref>', () => {
-  beforeAll(() => jest.spyOn(React, 'useEffect').mockImplementation(React.useLayoutEffect));
-  afterAll(() => (React.useEffect as any).mockRestore());
+  let mockUseEffect: any;
+  beforeEach(() => (mockUseEffect = jest.spyOn(React, 'useEffect').mockImplementation(React.useLayoutEffect)));
+  afterEach(() => mockUseEffect.mockRestore());
 
   let { router, routerGo, mountInRouter } = makeTestRouter([]);
   beforeEach(() => ({ router, routerGo, mountInRouter } = makeTestRouter(states)));
 
   it('renders its child with injected props', async () => {
     const wrapper = mountInRouter(
       <UISref to="state2">
-        <a>state2</a>
+        <a data-testid="anchor">state2</a>
       </UISref>
     );
     await routerGo('state');
-    const props = wrapper.find('a').props();
-    expect(typeof props.onClick).toBe('function');
-    expect(props.href.includes('/state2')).toBe(true);
+    const goSpy = jest.spyOn(router.stateService, 'go');
+    const anchor = wrapper.getByTestId('anchor');
+    expect(anchor.getAttribute('href').includes('/state2')).toBe(true);
+    anchor.click();
+    expect(goSpy).toHaveBeenCalledTimes(1);
   });
 
   it('throws if state name is not a string', () => {
@@ -50,27 +54,26 @@ describe('<UISref>', () => {
     const deregisterFn = jest.fn();
     const parentUISrefActiveAddStateFn = jest.fn(() => deregisterFn);
 
-    const wrapper = mountInRouter(
+    mountInRouter(
       <UISrefActiveContext.Provider value={parentUISrefActiveAddStateFn}>
         <UIView />
       </UISrefActiveContext.Provider>
     );
 
-    expect(wrapper.html()).toBe('<a href="/state2" class="">state2</a>');
     expect(parentUISrefActiveAddStateFn).toHaveBeenCalled();
     await routerGo('state2');
     expect(deregisterFn).toHaveBeenCalled();
   });
 
   it('triggers a transition to target state', async () => {
     const goSpy = jest.spyOn(router.stateService, 'go');
-    const wrapper = mountInRouter(
+    const rendered = mountInRouter(
       <UISref to="state2">
-        <a />
+        <a data-testid="anchor" />
       </UISref>
     );
 
-    wrapper.find('a').simulate('click');
+    rendered.getByTestId('anchor').click();
 
     expect(goSpy).toHaveBeenCalledTimes(1);
     expect(goSpy).toHaveBeenCalledWith('state2', expect.anything(), expect.anything());
@@ -80,12 +83,14 @@ describe('<UISref>', () => {
     const log = [];
     const goSpy = jest.spyOn(router.stateService, 'go').mockImplementation(() => log.push('go') as any);
     const onClickSpy = jest.fn(() => log.push('onClick'));
-    const wrapper = mountInRouter(
+    const rendered = mountInRouter(
       <UISref to="state2">
-        <a onClick={onClickSpy}>state2</a>
+        <a data-testid="anchor" onClick={onClickSpy}>
+          state2
+        </a>
       </UISref>
     );
-    wrapper.find('a').simulate('click');
+    rendered.getByTestId('anchor').click();
 
     expect(onClickSpy).toHaveBeenCalled();
     expect(goSpy).toHaveBeenCalled();
@@ -95,68 +100,71 @@ describe('<UISref>', () => {
   it('calls the child elements onClick function and honors e.preventDefault()', async () => {
     const goSpy = jest.spyOn(router.stateService, 'go');
     const onClickSpy = jest.fn((e) => e.preventDefault());
-    const wrapper = mountInRouter(
+    const rendered = mountInRouter(
       <UISref to="state2">
-        <a onClick={onClickSpy}>state2</a>
+        <a data-testid="anchor" onClick={onClickSpy}>
+          state2
+        </a>
       </UISref>
     );
-    wrapper.find('a').simulate('click');
+    rendered.getByTestId('anchor').click();
 
     expect(onClickSpy).toHaveBeenCalled();
     expect(goSpy).not.toHaveBeenCalled();
   });
 
   it("doesn't trigger a transition when middle-clicked", async () => {
     const stateServiceGoSpy = jest.spyOn(router.stateService, 'go');
-    const wrapper = mountInRouter(
+    const rendered = mountInRouter(
       <UISref to="state2">
-        <a>state2</a>
+        <a data-testid="anchor">state2</a>
       </UISref>
     );
 
-    const link = wrapper.find('a');
-    link.simulate('click');
+    const link = rendered.getByTestId('anchor');
+    link.click();
     expect(stateServiceGoSpy).toHaveBeenCalledTimes(1);
 
-    link.simulate('click', { button: 1 });
+    fireEvent(link, new MouseEvent('click', { button: 1 }));
     expect(stateServiceGoSpy).toHaveBeenCalledTimes(1);
   });
 
   it("doesn't trigger a transition when ctrl/meta/shift/alt+clicked", async () => {
     const stateServiceGoSpy = jest.spyOn(router.stateService, 'go');
-    const wrapper = mountInRouter(
+    const rendered = mountInRouter(
       <UISref to="state2">
-        <a>state2</a>
+        <a data-testid="anchor">state2</a>
       </UISref>
     );
 
-    const link = wrapper.find('a');
-    link.simulate('click');
+    const link = rendered.getByTestId('anchor');
+    link.click();
     expect(stateServiceGoSpy).toHaveBeenCalledTimes(1);
 
-    link.simulate('click', { ctrlKey: true });
+    fireEvent(link, new MouseEvent('click', { ctrlKey: true }));
     expect(stateServiceGoSpy).toHaveBeenCalledTimes(1);
 
-    link.simulate('click', { metaKey: true });
+    fireEvent(link, new MouseEvent('click', { metaKey: true }));
     expect(stateServiceGoSpy).toHaveBeenCalledTimes(1);
 
-    link.simulate('click', { shiftKey: true });
+    fireEvent(link, new MouseEvent('click', { shiftKey: true }));
     expect(stateServiceGoSpy).toHaveBeenCalledTimes(1);
 
-    link.simulate('click', { altKey: true });
+    fireEvent(link, new MouseEvent('click', { altKey: true }));
     expect(stateServiceGoSpy).toHaveBeenCalledTimes(1);
   });
 
   it("doesn't trigger a transition when the anchor has a 'target' attribute", async () => {
     const stateServiceGoSpy = jest.spyOn(router.stateService, 'go');
-    const wrapper = mountInRouter(
+    const rendered = mountInRouter(
       <UISref to="state2">
-        <a target="_blank">state2</a>
+        <a data-testid="anchor" target="_blank">
+          state2
+        </a>
       </UISref>
     );
 
-    const link = wrapper.find('a');
-    link.simulate('click');
+    rendered.getByTestId('anchor').click();
     expect(stateServiceGoSpy).not.toHaveBeenCalled();
   });
 });