diff --git a/packages/mui-base/src/Composite/Root/CompositeRoot.test.tsx b/packages/mui-base/src/Composite/Root/CompositeRoot.test.tsx
index e7fad1fab2..61b32c2386 100644
--- a/packages/mui-base/src/Composite/Root/CompositeRoot.test.tsx
+++ b/packages/mui-base/src/Composite/Root/CompositeRoot.test.tsx
@@ -1,15 +1,11 @@
 import * as React from 'react';
 import { expect } from 'chai';
 import { test } from 'mocha';
-import { createRenderer, act, screen, fireEvent } from '@mui/internal-test-utils';
+import { createRenderer, act, screen, fireEvent, flushMicrotasks } from '@mui/internal-test-utils';
 import { describeConformance } from '../../../test/describeConformance';
 import { CompositeRoot } from './CompositeRoot';
 import { CompositeItem } from '../Item/CompositeItem';
 
-function microtask() {
-  return act(async () => {});
-}
-
 describe('<CompositeRoot />', () => {
   const { render } = createRenderer();
 
@@ -38,25 +34,25 @@ describe('<CompositeRoot />', () => {
       expect(screen.getByTestId('1')).to.have.attribute('data-active');
 
       fireEvent.keyDown(screen.getByTestId('1'), { key: 'ArrowDown' });
-      await microtask();
+      await flushMicrotasks();
       expect(screen.getByTestId('2')).to.have.attribute('data-active');
       expect(screen.getByTestId('2')).to.have.attribute('tabindex', '0');
       expect(screen.getByTestId('2')).toHaveFocus();
 
       fireEvent.keyDown(screen.getByTestId('2'), { key: 'ArrowDown' });
-      await microtask();
+      await flushMicrotasks();
       expect(screen.getByTestId('3')).to.have.attribute('data-active');
       expect(screen.getByTestId('3')).to.have.attribute('tabindex', '0');
       expect(screen.getByTestId('3')).toHaveFocus();
 
       fireEvent.keyDown(screen.getByTestId('3'), { key: 'ArrowUp' });
-      await microtask();
+      await flushMicrotasks();
       expect(screen.getByTestId('2')).to.have.attribute('data-active');
       expect(screen.getByTestId('2')).to.have.attribute('tabindex', '0');
       expect(screen.getByTestId('2')).toHaveFocus();
 
       act(() => screen.getByTestId('1').focus());
-      await microtask();
+      await flushMicrotasks();
       expect(screen.getByTestId('1')).to.have.attribute('data-active');
       expect(screen.getByTestId('1')).to.have.attribute('tabindex', '0');
     });
@@ -74,25 +70,25 @@ describe('<CompositeRoot />', () => {
       expect(screen.getByTestId('1')).to.have.attribute('data-active');
 
       fireEvent.keyDown(screen.getByTestId('1'), { key: 'ArrowDown' });
-      await microtask();
+      await flushMicrotasks();
       expect(screen.getByTestId('2')).to.have.attribute('data-active');
       expect(screen.getByTestId('2')).to.have.attribute('tabindex', '0');
       expect(screen.getByTestId('2')).toHaveFocus();
 
       fireEvent.keyDown(screen.getByTestId('2'), { key: 'ArrowDown' });
-      await microtask();
+      await flushMicrotasks();
       expect(screen.getByTestId('3')).to.have.attribute('data-active');
       expect(screen.getByTestId('3')).to.have.attribute('tabindex', '0');
       expect(screen.getByTestId('3')).toHaveFocus();
 
       fireEvent.keyDown(screen.getByTestId('3'), { key: 'ArrowUp' });
-      await microtask();
+      await flushMicrotasks();
       expect(screen.getByTestId('2')).to.have.attribute('data-active');
       expect(screen.getByTestId('2')).to.have.attribute('tabindex', '0');
       expect(screen.getByTestId('2')).toHaveFocus();
 
       act(() => screen.getByTestId('1').focus());
-      await microtask();
+      await flushMicrotasks();
       expect(screen.getByTestId('1')).to.have.attribute('data-active');
       expect(screen.getByTestId('1')).to.have.attribute('tabindex', '0');
     });
@@ -119,37 +115,37 @@ describe('<CompositeRoot />', () => {
       expect(screen.getByTestId('1')).to.have.attribute('data-active');
 
       fireEvent.keyDown(screen.getByTestId('1'), { key: 'ArrowDown' });
-      await microtask();
+      await flushMicrotasks();
       expect(screen.getByTestId('4')).to.have.attribute('data-active');
       expect(screen.getByTestId('4')).to.have.attribute('tabindex', '0');
       expect(screen.getByTestId('4')).toHaveFocus();
 
       fireEvent.keyDown(screen.getByTestId('4'), { key: 'ArrowRight' });
-      await microtask();
+      await flushMicrotasks();
       expect(screen.getByTestId('5')).to.have.attribute('data-active');
       expect(screen.getByTestId('5')).to.have.attribute('tabindex', '0');
       expect(screen.getByTestId('5')).toHaveFocus();
 
       fireEvent.keyDown(screen.getByTestId('5'), { key: 'ArrowDown' });
-      await microtask();
+      await flushMicrotasks();
       expect(screen.getByTestId('8')).to.have.attribute('data-active');
       expect(screen.getByTestId('8')).to.have.attribute('tabindex', '0');
       expect(screen.getByTestId('8')).toHaveFocus();
 
       fireEvent.keyDown(screen.getByTestId('8'), { key: 'ArrowLeft' });
-      await microtask();
+      await flushMicrotasks();
       expect(screen.getByTestId('7')).to.have.attribute('data-active');
       expect(screen.getByTestId('7')).to.have.attribute('tabindex', '0');
       expect(screen.getByTestId('7')).toHaveFocus();
 
       fireEvent.keyDown(screen.getByTestId('7'), { key: 'ArrowUp' });
-      await microtask();
+      await flushMicrotasks();
       expect(screen.getByTestId('4')).to.have.attribute('data-active');
       expect(screen.getByTestId('4')).to.have.attribute('tabindex', '0');
       expect(screen.getByTestId('4')).toHaveFocus();
 
       act(() => screen.getByTestId('9').focus());
-      await microtask();
+      await flushMicrotasks();
       expect(screen.getByTestId('9')).to.have.attribute('data-active');
       expect(screen.getByTestId('9')).to.have.attribute('tabindex', '0');
     });
@@ -185,37 +181,37 @@ describe('<CompositeRoot />', () => {
       expect(screen.getByTestId('1')).to.have.attribute('data-active');
 
       fireEvent.keyDown(screen.getByTestId('1'), { key: 'ArrowDown' });
-      await microtask();
+      await flushMicrotasks();
       expect(screen.getByTestId('456')).to.have.attribute('data-active');
       expect(screen.getByTestId('456')).to.have.attribute('tabindex', '0');
       expect(screen.getByTestId('456')).toHaveFocus();
 
       fireEvent.keyDown(screen.getByTestId('456'), { key: 'ArrowDown' });
-      await microtask();
+      await flushMicrotasks();
       expect(screen.getByTestId('7')).to.have.attribute('data-active');
       expect(screen.getByTestId('7')).to.have.attribute('tabindex', '0');
       expect(screen.getByTestId('7')).toHaveFocus();
 
       fireEvent.keyDown(screen.getByTestId('7'), { key: 'ArrowRight' });
-      await microtask();
+      await flushMicrotasks();
       expect(screen.getByTestId('8')).to.have.attribute('data-active');
       expect(screen.getByTestId('8')).to.have.attribute('tabindex', '0');
       expect(screen.getByTestId('8')).toHaveFocus();
 
       fireEvent.keyDown(screen.getByTestId('8'), { key: 'ArrowUp' });
-      await microtask();
+      await flushMicrotasks();
       expect(screen.getByTestId('456')).to.have.attribute('data-active');
       expect(screen.getByTestId('456')).to.have.attribute('tabindex', '0');
       expect(screen.getByTestId('456')).toHaveFocus();
 
       fireEvent.keyDown(screen.getByTestId('456'), { key: 'ArrowUp' });
-      await microtask();
+      await flushMicrotasks();
       expect(screen.getByTestId('1')).to.have.attribute('data-active');
       expect(screen.getByTestId('1')).to.have.attribute('tabindex', '0');
       expect(screen.getByTestId('1')).toHaveFocus();
 
       act(() => screen.getByTestId('9').focus());
-      await microtask();
+      await flushMicrotasks();
       expect(screen.getByTestId('9')).to.have.attribute('data-active');
       expect(screen.getByTestId('9')).to.have.attribute('tabindex', '0');
     });
@@ -250,37 +246,37 @@ describe('<CompositeRoot />', () => {
       expect(screen.getByTestId('1')).to.have.attribute('data-active');
 
       fireEvent.keyDown(screen.getByTestId('1'), { key: 'ArrowDown' });
-      await microtask();
+      await flushMicrotasks();
       expect(screen.getByTestId('4578')).to.have.attribute('data-active');
       expect(screen.getByTestId('4578')).to.have.attribute('tabindex', '0');
       expect(screen.getByTestId('4578')).toHaveFocus();
 
       fireEvent.keyDown(screen.getByTestId('4578'), { key: 'ArrowRight' });
-      await microtask();
+      await flushMicrotasks();
       expect(screen.getByTestId('6')).to.have.attribute('data-active');
       expect(screen.getByTestId('6')).to.have.attribute('tabindex', '0');
       expect(screen.getByTestId('6')).toHaveFocus();
 
       fireEvent.keyDown(screen.getByTestId('6'), { key: 'ArrowDown' });
-      await microtask();
+      await flushMicrotasks();
       expect(screen.getByTestId('9')).to.have.attribute('data-active');
       expect(screen.getByTestId('9')).to.have.attribute('tabindex', '0');
       expect(screen.getByTestId('9')).toHaveFocus();
 
       fireEvent.keyDown(screen.getByTestId('9'), { key: 'ArrowLeft' });
-      await microtask();
+      await flushMicrotasks();
       expect(screen.getByTestId('4578')).to.have.attribute('data-active');
       expect(screen.getByTestId('4578')).to.have.attribute('tabindex', '0');
       expect(screen.getByTestId('4578')).toHaveFocus();
 
       fireEvent.keyDown(screen.getByTestId('4578'), { key: 'ArrowUp' });
-      await microtask();
+      await flushMicrotasks();
       expect(screen.getByTestId('1')).to.have.attribute('data-active');
       expect(screen.getByTestId('1')).to.have.attribute('tabindex', '0');
       expect(screen.getByTestId('1')).toHaveFocus();
 
       act(() => screen.getByTestId('9').focus());
-      await microtask();
+      await flushMicrotasks();
       expect(screen.getByTestId('9')).to.have.attribute('data-active');
       expect(screen.getByTestId('9')).to.have.attribute('tabindex', '0');
     });
@@ -314,7 +310,7 @@ describe('<CompositeRoot />', () => {
       expect(screen.getByTestId('1')).to.have.attribute('data-active');
 
       fireEvent.keyDown(screen.getByTestId('1'), { key: 'ArrowDown' });
-      await microtask();
+      await flushMicrotasks();
       expect(screen.getByTestId('78')).to.have.attribute('data-active');
       expect(screen.getByTestId('78')).to.have.attribute('tabindex', '0');
       expect(screen.getByTestId('78')).toHaveFocus();
@@ -350,13 +346,13 @@ describe('<CompositeRoot />', () => {
       expect(screen.getByTestId('1')).to.have.attribute('data-active');
 
       fireEvent.keyDown(screen.getByTestId('1'), { key: 'ArrowDown' });
-      await microtask();
+      await flushMicrotasks();
       expect(screen.getByTestId('4')).to.have.attribute('data-active');
       expect(screen.getByTestId('4')).to.have.attribute('tabindex', '0');
       expect(screen.getByTestId('4')).toHaveFocus();
 
       fireEvent.keyDown(screen.getByTestId('4'), { key: 'ArrowDown' });
-      await microtask();
+      await flushMicrotasks();
       expect(screen.getByTestId('78')).to.have.attribute('data-active');
       expect(screen.getByTestId('78')).to.have.attribute('tabindex', '0');
       expect(screen.getByTestId('78')).toHaveFocus();
diff --git a/packages/mui-base/src/RadioGroup/Root/RadioGroupRoot.test.tsx b/packages/mui-base/src/RadioGroup/Root/RadioGroupRoot.test.tsx
index ca2381c591..e141c83a43 100644
--- a/packages/mui-base/src/RadioGroup/Root/RadioGroupRoot.test.tsx
+++ b/packages/mui-base/src/RadioGroup/Root/RadioGroupRoot.test.tsx
@@ -1,10 +1,10 @@
 import * as React from 'react';
+import * as RadioGroup from '@base_ui/react/RadioGroup';
+import * as Radio from '@base_ui/react/Radio';
 import { expect } from 'chai';
 import { spy } from 'sinon';
-import { createRenderer, act, screen } from '@mui/internal-test-utils';
+import { createRenderer, act, screen, fireEvent } from '@mui/internal-test-utils';
 import userEvent from '@testing-library/user-event';
-import * as RadioGroup from '@base_ui/react/RadioGroup';
-import * as Radio from '@base_ui/react/Radio';
 import { describeConformance } from '../../../test/describeConformance';
 
 const isJSDOM = /jsdom/.test(window.navigator.userAgent);
@@ -22,6 +22,7 @@ describe('<RadioGroup.Root />', () => {
   describe('extra props', () => {
     it('can override the built-in attributes', () => {
       const { container } = render(<RadioGroup.Root role="switch" />);
+      // eslint-disable-next-line testing-library/no-node-access
       expect(container.firstElementChild as HTMLElement).to.have.attribute('role', 'switch');
     });
   });
@@ -36,9 +37,7 @@ describe('<RadioGroup.Root />', () => {
 
     const item = screen.getByTestId('item');
 
-    act(() => {
-      item.click();
-    });
+    fireEvent.click(item);
 
     expect(handleChange.callCount).to.equal(1);
     expect(handleChange.firstCall.args[0]).to.equal('a');
@@ -66,9 +65,7 @@ describe('<RadioGroup.Root />', () => {
 
       expect(item).to.have.attribute('aria-checked', 'false');
 
-      act(() => {
-        item.click();
-      });
+      fireEvent.click(item);
 
       expect(item).to.have.attribute('aria-checked', 'false');
     });
@@ -98,9 +95,7 @@ describe('<RadioGroup.Root />', () => {
 
       expect(item).to.have.attribute('aria-checked', 'false');
 
-      act(() => {
-        item.click();
-      });
+      fireEvent.click(item);
 
       expect(item).to.have.attribute('aria-checked', 'false');
     });
@@ -116,6 +111,7 @@ describe('<RadioGroup.Root />', () => {
     const group = screen.getByTestId('root');
     const item = screen.getByTestId('item');
 
+    // eslint-disable-next-line testing-library/no-node-access
     const input = group.querySelector('input');
 
     act(() => {
@@ -156,6 +152,7 @@ describe('<RadioGroup.Root />', () => {
   it('should set the name attribute on the input', () => {
     render(<RadioGroup.Root name="radio-group" />);
     const group = screen.getByRole('radiogroup');
+    // eslint-disable-next-line testing-library/no-node-access
     expect(group.nextElementSibling).to.have.attribute('name', 'radio-group');
   });