[core] Set up eslint-plugin-testing-library

.eslintrc.js

@@ -276,6 +276,21 @@ module.exports = {
         'react/no-unused-prop-types': 'off',
       },
     },
+    {
+      files: [
+        // matching the pattern of the test runner
+        '*.test.mjs',
+        '*.test.js',
+        '*.test.ts',
+        '*.test.tsx',
+      ],
+      excludedFiles: ['packages/markdown/**/*', 'test/e2e/**/*', 'test/regressions/**/*'],
+      extends: ['plugin:testing-library/react'],
+      rules: {
+        'testing-library/no-container': 'off',
+        'testing-library/prefer-screen-queries': 'off',
+      },
+    },
     {
       files: ['docs/src/modules/components/**/*.js'],
       rules: {

package.json

@@ -154,6 +154,7 @@
     "eslint-plugin-react": "^7.34.4",
     "eslint-plugin-react-compiler": "0.0.0-experimental-0998c1e-20240625",
     "eslint-plugin-react-hooks": "^4.6.2",
+    "eslint-plugin-testing-library": "^6.2.2",
     "fast-glob": "^3.3.2",
     "fs-extra": "^11.2.0",
     "globby": "^14.0.2",

packages-internal/test-utils/src/mochaHooks.test.js

@@ -83,6 +83,7 @@ describe('mochaHooks', () => {
         // not wrapped in act()
         unsafeSetState(1);
         // make sure effects are flushed
+        // eslint-disable-next-line testing-library/no-unnecessary-act
         act(() => {});
       });
 

packages/mui-base/src/Button/Button.test.tsx

@@ -67,6 +67,7 @@ describe('<Button />', () => {
         const { getByRole } = render(<Button focusableWhenDisabled disabled />);
 
         const button = getByRole('button');
+
         act(() => {
           button.focus();
         });
@@ -83,14 +84,12 @@ describe('<Button />', () => {
         const button = getByRole('button');
         act(() => {
           button.focus();
-        });
-
-        act(() => {
           button.click();
-          fireEvent.keyDown(button, { key: 'Enter' });
-          fireEvent.keyUp(button, { key: ' ' });
         });
 
+        fireEvent.keyDown(button, { key: 'Enter' });
+        fireEvent.keyUp(button, { key: ' ' });
+
         expect(handleClick.callCount).to.equal(0);
       });
     });
@@ -129,14 +128,12 @@ describe('<Button />', () => {
         const button = getByRole('button');
         act(() => {
           button.focus();
-        });
-
-        act(() => {
           button.click();
-          fireEvent.keyDown(button, { key: 'Enter' });
-          fireEvent.keyUp(button, { key: ' ' });
         });
 
+        fireEvent.keyDown(button, { key: 'Enter' });
+        fireEvent.keyUp(button, { key: ' ' });
+
         expect(handleClick.callCount).to.equal(0);
       });
     });

packages/mui-base/src/ClickAwayListener/ClickAwayListener.test.js

@@ -25,6 +25,7 @@ describe('<ClickAwayListener />', () => {
    * React bug: https://github.com/facebook/react/issues/20074
    */
   function render(...args) {
+    // eslint-disable-next-line testing-library/render-result-naming-convention
     const result = clientRender(...args);
     clock.tick(0);
     return result;

packages/mui-base/src/Dropdown/Dropdown.test.tsx

@@ -22,6 +22,7 @@ describe('<Dropdown />', () => {
     element: React.ReactElement<any, string | React.JSXElementConstructor<any>>,
     options?: RenderOptions,
   ): Promise<MuiRenderResult> {
+    // eslint-disable-next-line testing-library/render-result-naming-convention
     const rendered = internalRender(element, options);
     await flushMicrotasks();
     return rendered;

packages/mui-base/src/Menu/Menu.test.tsx

@@ -32,6 +32,7 @@ describe('<Menu />', () => {
     element: React.ReactElement<any, string | React.JSXElementConstructor<any>>,
     options?: RenderOptions,
   ): Promise<MuiRenderResult> {
+    // eslint-disable-next-line testing-library/render-result-naming-convention
     const rendered = internalRender(element, options);
     await flushMicrotasks();
     return rendered;

packages/mui-base/src/MenuButton/MenuButton.test.tsx

@@ -98,7 +98,7 @@ describe('<MenuButton />', () => {
         button.focus();
       });
 
-      expect(document.activeElement).to.equal(button);
+      expect(button).toHaveFocus();
     });
   });
 

packages/mui-base/src/Select/Select.test.tsx

@@ -9,6 +9,7 @@ import {
   MuiRenderResult,
   RenderOptions,
   flushMicrotasks,
+  within,
 } from '@mui/internal-test-utils';
 import userEvent from '@testing-library/user-event';
 import { Select, SelectListboxSlotProps, selectClasses } from '@mui/base/Select';
@@ -28,6 +29,7 @@ describe('<Select />', () => {
     element: React.ReactElement<any, string | React.JSXElementConstructor<any>>,
     options?: RenderOptions,
   ): Promise<MuiRenderResult> {
+    // eslint-disable-next-line testing-library/render-result-naming-convention
     const rendered = internalRender(element, options);
     await flushMicrotasks();
     return rendered;
@@ -918,15 +920,15 @@ describe('<Select />', () => {
     });
 
     it('renders a zero-width space when there is no selected value nor placeholder and renderValue is not provided', async () => {
-      const { getByRole } = await render(
+      await render(
         <Select>
           <Option value={1}>One</Option>
           <Option value={2}>Two</Option>
         </Select>,
       );
 
-      const select = getByRole('combobox');
-      const zws = select.querySelector('.notranslate');
+      const select = screen.getByRole('combobox');
+      const zws = within(select).getByText('​'); // zero-width space
 
       expect(zws).not.to.equal(null);
     });
@@ -1160,7 +1162,7 @@ describe('<Select />', () => {
       );
 
       const input = getAllByRole('textbox')[0];
-      expect(document.activeElement).to.equal(input);
+      expect(input).toHaveFocus();
     });
 
     it('scrolls to initially highlighted option after opening', async function test() {
@@ -1219,7 +1221,7 @@ describe('<Select />', () => {
       );
 
       const select = getByRole('combobox');
-      expect(document.activeElement).to.equal(select);
+      expect(select).toHaveFocus();
     });
   });
 
@@ -1346,15 +1348,15 @@ describe('<Select />', () => {
   describe('browser autofill', () => {
     it('sets value and calls external onChange when browser autofills', async () => {
       const onChangeHandler = spy();
-      const { container } = await render(
+      await render(
         <Select onChange={onChangeHandler} defaultValue="germany" autoComplete="country">
           <Option value="france">France</Option>
           <Option value="germany">Germany</Option>
           <Option value="china">China</Option>
         </Select>,
       );
 
-      const hiddenInput = container.querySelector('[autocomplete="country"]');
+      const hiddenInput = screen.getByRole('textbox', { hidden: true });
 
       expect(hiddenInput).not.to.eq(null);
       expect(hiddenInput).to.have.value('germany');
@@ -1372,15 +1374,15 @@ describe('<Select />', () => {
 
     it('does not set value when browser autofills invalid value', async () => {
       const onChangeHandler = spy();
-      const { container } = await render(
+      await render(
         <Select onChange={onChangeHandler} defaultValue="germany" autoComplete="country">
           <Option value="france">France</Option>
           <Option value="germany">Germany</Option>
           <Option value="china">China</Option>
         </Select>,
       );
 
-      const hiddenInput = container.querySelector('[autocomplete="country"]');
+      const hiddenInput = screen.getByRole('textbox', { hidden: true });
 
       expect(hiddenInput).not.to.eq(null);
       expect(hiddenInput).to.have.value('germany');
@@ -1397,15 +1399,15 @@ describe('<Select />', () => {
 
     it('clears value and calls external onChange when browser clears autofill', async () => {
       const onChangeHandler = spy();
-      const { container } = await render(
+      await render(
         <Select onChange={onChangeHandler} defaultValue="germany" autoComplete="country">
           <Option value="france">France</Option>
           <Option value="germany">Germany</Option>
           <Option value="china">China</Option>
         </Select>,
       );
 
-      const hiddenInput = container.querySelector('[autocomplete="country"]');
+      const hiddenInput = screen.getByRole('textbox', { hidden: true });
 
       expect(hiddenInput).not.to.eq(null);
       expect(hiddenInput).to.have.value('germany');

packages/mui-base/src/Snackbar/Snackbar.test.tsx

@@ -18,6 +18,7 @@ describe('<Snackbar />', () => {
    * React bug: https://github.com/facebook/react/issues/20074
    */
   function render(...args: [React.ReactElement<any>]) {
+    // eslint-disable-next-line testing-library/render-result-naming-convention
     const result = clientRender(...args);
     clock.tick(0);
     return result;

packages/mui-base/src/Unstable_NumberInput/NumberInput.test.tsx

@@ -357,21 +357,21 @@ describe('<NumberInput />', () => {
       const incrementButton = getByTestId('increment-btn');
       const decrementButton = getByTestId('decrement-btn');
 
-      expect(document.activeElement).to.equal(document.body);
+      expect(document.body).toHaveFocus();
 
       await userEvent.click(incrementButton);
 
-      expect(document.activeElement).to.equal(input);
+      expect(input).toHaveFocus();
 
       act(() => {
         input.blur();
       });
 
-      expect(document.activeElement).to.equal(document.body);
+      expect(document.body).toHaveFocus();
 
       await userEvent.click(decrementButton);
 
-      expect(document.activeElement).to.equal(input);
+      expect(input).toHaveFocus();
     });
   });
 
@@ -554,13 +554,13 @@ describe('<NumberInput />', () => {
       const { getByRole } = render(<NumberInput />);
 
       const input = getByRole('textbox') as HTMLInputElement;
-      expect(document.activeElement).to.equal(document.body);
+      expect(document.body).toHaveFocus();
 
       await userEvent.keyboard('[Tab]');
-      expect(document.activeElement).to.equal(input);
+      expect(input).toHaveFocus();
 
       await userEvent.keyboard('[Tab]');
-      expect(document.activeElement).to.equal(document.body);
+      expect(document.body).toHaveFocus();
     });
   });
 
@@ -600,9 +600,7 @@ describe('<NumberInput />', () => {
     const input = getByRole('textbox') as HTMLInputElement;
     const button = getByTestId('button') as HTMLButtonElement;
 
-    act(() => {
-      fireEvent.click(button);
-    });
+    fireEvent.click(button);
 
     await userEvent.click(input);
     expect(input.value).to.equal('20');

packages/mui-base/src/Unstable_Popup/Popup.test.tsx

@@ -52,6 +52,7 @@ describe('<Popup />', () => {
   describeConformanceUnstyled(<Popup {...defaultProps} />, () => ({
     inheritComponent: 'div',
     render: async (...renderArgs) => {
+      // eslint-disable-next-line testing-library/render-result-naming-convention
       const result = render(...renderArgs);
       await waitForPosition();
 

packages/mui-base/src/unstable_useNumberInput/useNumberInput.test.tsx

@@ -132,7 +132,7 @@ describe('useNumberInput', () => {
       expect(handleChange.callCount).to.equal(0);
 
       await userEvent.keyboard('[Tab]');
-      expect(document.activeElement).to.equal(document.body);
+      expect(document.body).toHaveFocus();
 
       expect(handleChange.callCount).to.equal(1);
       expect(handleChange.args[0][1]).to.equal(34);
@@ -180,7 +180,7 @@ describe('useNumberInput', () => {
       await userEvent.keyboard('9');
 
       await userEvent.keyboard('[Tab]');
-      expect(document.activeElement).to.equal(document.body);
+      expect(document.body).toHaveFocus();
 
       expect(handleChange.args[0][1]).to.equal(5);
     });
@@ -204,7 +204,7 @@ describe('useNumberInput', () => {
       await userEvent.keyboard('-9');
 
       await userEvent.keyboard('[Tab]');
-      expect(document.activeElement).to.equal(document.body);
+      expect(document.body).toHaveFocus();
 
       expect(handleChange.args[0][1]).to.equal(5);
     });
@@ -229,7 +229,7 @@ describe('useNumberInput', () => {
       await userEvent.keyboard('4');
 
       await userEvent.keyboard('[Tab]');
-      expect(document.activeElement).to.equal(document.body);
+      expect(document.body).toHaveFocus();
 
       expect(handleChange.args[0][1]).to.equal(5);
     });
@@ -254,7 +254,7 @@ describe('useNumberInput', () => {
       expect(input.value).to.equal('');
 
       await userEvent.keyboard('[Tab]');
-      expect(document.activeElement).to.equal(document.body);
+      expect(document.body).toHaveFocus();
 
       expect(handleChange.callCount).to.equal(1);
       expect(handleChange.args[0][1]).to.equal(null);
@@ -280,7 +280,7 @@ describe('useNumberInput', () => {
       expect(input.value).to.equal('-');
 
       await userEvent.keyboard('[Tab]');
-      expect(document.activeElement).to.equal(document.body);
+      expect(document.body).toHaveFocus();
 
       expect(handleChange.callCount).to.equal(1);
       expect(handleChange.args[0][1]).to.equal(null);

packages/mui-base/src/useAutocomplete/useAutocomplete.test.js

@@ -1,6 +1,6 @@
 import * as React from 'react';
 import { expect } from 'chai';
-import { createRenderer, screen, ErrorBoundary, act, fireEvent } from '@mui/internal-test-utils';
+import { createRenderer, screen, ErrorBoundary, fireEvent } from '@mui/internal-test-utils';
 import { spy } from 'sinon';
 import { useAutocomplete, createFilterOptions } from '@mui/base/useAutocomplete';
 
@@ -319,10 +319,8 @@ describe('useAutocomplete', () => {
       render(<Test options={['foo', 'bar']} />);
       const input = screen.getByRole('combobox');
 
-      act(() => {
-        fireEvent.change(input, { target: { value: 'free' } });
-        input.blur();
-      });
+      fireEvent.change(input, { target: { value: 'free' } });
+      fireEvent.blur(input);
 
       expect(input.value).to.equal('free');
     });

packages/mui-joy/src/Accordion/Accordion.test.tsx

@@ -121,13 +121,13 @@ describe('<Accordion />', () => {
   });
 
   it('should warn when switching from controlled to uncontrolled', () => {
-    const wrapper = render(
+    const { setProps } = render(
       <Accordion expanded>
         <AccordionSummary>Header</AccordionSummary>
       </Accordion>,
     );
 
-    expect(() => wrapper.setProps({ expanded: undefined })).to.toErrorDev(
+    expect(() => setProps({ expanded: undefined })).to.toErrorDev(
       'MUI: A component is changing the controlled expanded state of Accordion to be uncontrolled.',
     );
   });