diff --git a/packages/ra-core/src/core/RoutesWithLayout.spec.tsx b/packages/ra-core/src/core/RoutesWithLayout.spec.tsx
index 6f68767f91d..17c0f30ae26 100644
--- a/packages/ra-core/src/core/RoutesWithLayout.spec.tsx
+++ b/packages/ra-core/src/core/RoutesWithLayout.spec.tsx
@@ -3,7 +3,6 @@ import { Route, MemoryRouter } from 'react-router-dom';
 import { createStore } from 'redux';
 import { Provider } from 'react-redux';
 import { render, cleanup } from '@testing-library/react';
-import assert from 'assert';
 
 import RoutesWithLayout from './RoutesWithLayout';
 
@@ -34,7 +33,7 @@ describe('<RoutesWithLayout>', () => {
             </Provider>
         );
 
-        assert.notEqual(queryByText('Dashboard'), null);
+        expect(queryByText('Dashboard')).not.toBeNull();
     });
 
     it('should show the first resource on / when there is only one resource and no dashboard', () => {
@@ -48,7 +47,7 @@ describe('<RoutesWithLayout>', () => {
             </Provider>
         );
 
-        assert.notEqual(queryByText('Default'), null);
+        expect(queryByText('Default')).not.toBeNull();
     });
 
     it('should show the first resource on / when there are multiple resource and no dashboard', () => {
@@ -64,8 +63,8 @@ describe('<RoutesWithLayout>', () => {
             </Provider>
         );
 
-        assert.notEqual(queryByText('Default'), null);
-        assert.equal(queryByText('Resource'), null);
+        expect(queryByText('Default')).not.toBeNull();
+        expect(queryByText('Resource')).toBeNull();
     });
 
     it('should accept custom routes', () => {
@@ -83,6 +82,7 @@ describe('<RoutesWithLayout>', () => {
                 </MemoryRouter>
             </Provider>
         );
-        assert.notEqual(queryByText('Custom'), null);
+
+        expect(queryByText('Custom')).not.toBeNull();
     });
 });
diff --git a/packages/ra-core/src/form/FormField.spec.tsx b/packages/ra-core/src/form/FormField.spec.tsx
index 449a03b34fe..93e60a9003f 100644
--- a/packages/ra-core/src/form/FormField.spec.tsx
+++ b/packages/ra-core/src/form/FormField.spec.tsx
@@ -1,7 +1,6 @@
-import assert from 'assert';
-import { render, fireEvent, cleanup } from '@testing-library/react';
-import { Form } from 'react-final-form';
 import React from 'react';
+import { Form } from 'react-final-form';
+import { render, fireEvent, cleanup } from '@testing-library/react';
 import FormField from './FormField';
 
 describe('<FormField>', () => {
@@ -22,7 +21,7 @@ describe('<FormField>', () => {
         );
         const input = getByRole('textbox');
         fireEvent.change(input, { target: { value: 'Lorem' } });
-        assert.equal(formApi.getState().values.title, 'Lorem');
+        expect(formApi.getState().values.title).toEqual('Lorem');
     });
 
     it('should not render a <Field /> component if the field has an input', () => {
@@ -40,6 +39,6 @@ describe('<FormField>', () => {
         );
         const input = getByRole('textbox');
         fireEvent.change(input, { target: { value: 'Lorem' } });
-        assert.notEqual(formApi.getState().values.title, 'Lorem');
+        expect(formApi.getState().values.title).not.toEqual('Lorem');
     });
 });
diff --git a/packages/ra-ui-materialui/src/field/FunctionField.spec.js b/packages/ra-ui-materialui/src/field/FunctionField.spec.js
index 26e99fa6e20..16ad3a897f5 100644
--- a/packages/ra-ui-materialui/src/field/FunctionField.spec.js
+++ b/packages/ra-ui-materialui/src/field/FunctionField.spec.js
@@ -1,5 +1,4 @@
 import React from 'react';
-import assert from 'assert';
 import { render, cleanup } from '@testing-library/react';
 import FunctionField from './FunctionField';
 
@@ -11,7 +10,7 @@ describe('<FunctionField />', () => {
         const { queryByText } = render(
             <FunctionField record={record} render={r => r.foo.substr(0, 2)} />
         );
-        assert.notEqual(queryByText('ba'), null);
+        expect(queryByText('ba')).not.toBeNull();
     });
 
     it('should use custom className', () => {
@@ -22,6 +21,6 @@ describe('<FunctionField />', () => {
                 className="foo"
             />
         );
-        assert.ok(queryByText('bar').classList.contains('foo'));
+        expect(queryByText('bar').classList).toContain('foo');
     });
 });
diff --git a/packages/ra-ui-materialui/src/list/DatagridCell.spec.js b/packages/ra-ui-materialui/src/list/DatagridCell.spec.js
index d3aa6128a0c..8554d42eacf 100644
--- a/packages/ra-ui-materialui/src/list/DatagridCell.spec.js
+++ b/packages/ra-ui-materialui/src/list/DatagridCell.spec.js
@@ -1,4 +1,3 @@
-import assert from 'assert';
 import React from 'react';
 import PropTypes from 'prop-types';
 import { render, cleanup } from '@testing-library/react';
@@ -15,6 +14,8 @@ const renderWithTable = element =>
     );
 
 describe('<DatagridCell />', () => {
+    afterEach(cleanup);
+
     const Field = ({ basePath }) => <div>{basePath}</div>;
     Field.propTypes = {
         type: PropTypes.string,
@@ -29,20 +30,20 @@ describe('<DatagridCell />', () => {
         const { getByRole } = renderWithTable(
             <DatagridCell field={<Field />} />
         );
-        assert.equal(getByRole('cell').className, 'MuiTableCell-root');
+        expect(getByRole('cell').className).toEqual('MuiTableCell-root');
     });
 
     it('should pass the Datagrid basePath by default', () => {
         const { queryByText } = renderWithTable(
             <DatagridCell basePath="default" field={<Field />} />
         );
-        assert.notEqual(queryByText('default'), null);
+        expect(queryByText('default')).not.toBeNull();
     });
 
     it('should allow to overwrite the `basePath` field', () => {
         const { queryByText } = renderWithTable(
             <DatagridCell basePath="default" field={<Field basePath="new" />} />
         );
-        assert.notEqual(queryByText('new'), null);
+        expect(queryByText('new')).not.toBeNull();
     });
 });
diff --git a/packages/ra-ui-materialui/src/list/SingleFieldList.spec.js b/packages/ra-ui-materialui/src/list/SingleFieldList.spec.js
index 658f72327d0..61666eee390 100644
--- a/packages/ra-ui-materialui/src/list/SingleFieldList.spec.js
+++ b/packages/ra-ui-materialui/src/list/SingleFieldList.spec.js
@@ -1,5 +1,4 @@
 import React from 'react';
-import assert from 'assert';
 import { render, cleanup } from '@testing-library/react';
 import { createMemoryHistory } from 'history';
 import { Router } from 'react-router-dom';
@@ -34,8 +33,8 @@ describe('<SingleFieldList />', () => {
             </SingleFieldList>
         );
         const linkElements = queryAllByRole('link');
-        assert.equal(linkElements.length, 2);
-        assert.deepEqual(linkElements.map(link => link.getAttribute('href')), [
+        expect(linkElements).toHaveLength(2);
+        expect(linkElements.map(link => link.getAttribute('href'))).toEqual([
             '/posts/1',
             '/posts/2',
         ]);
@@ -56,8 +55,8 @@ describe('<SingleFieldList />', () => {
             </SingleFieldList>
         );
         const linkElements = queryAllByRole('link');
-        assert.equal(linkElements.length, 2);
-        assert.deepEqual(linkElements.map(link => link.getAttribute('href')), [
+        expect(linkElements).toHaveLength(2);
+        expect(linkElements.map(link => link.getAttribute('href'))).toEqual([
             '/posts/1',
             '/posts/2',
         ]);
@@ -79,9 +78,8 @@ describe('<SingleFieldList />', () => {
                 </SingleFieldList>
             );
             const linkElements = queryAllByRole('link');
-            assert.equal(linkElements.length, 2);
-            assert.deepEqual(
-                linkElements.map(link => link.getAttribute('href')),
+            expect(linkElements).toHaveLength(2);
+            expect(linkElements.map(link => link.getAttribute('href'))).toEqual(
                 [`/${action}/1`, `/${action}/2`]
             );
             cleanup();
@@ -105,8 +103,8 @@ describe('<SingleFieldList />', () => {
         );
 
         const linkElements = queryAllByRole('link');
-        assert.equal(linkElements.length, 2);
-        assert.deepEqual(linkElements.map(link => link.getAttribute('href')), [
+        expect(linkElements).toHaveLength(2);
+        expect(linkElements.map(link => link.getAttribute('href'))).toEqual([
             '/prefix/bar/1/show',
             '/prefix/bar/2/show',
         ]);
@@ -129,9 +127,8 @@ describe('<SingleFieldList />', () => {
                 </SingleFieldList>
             );
             const linkElements = queryAllByRole('link');
-            assert.equal(linkElements.length, 2);
-            assert.deepEqual(
-                linkElements.map(link => link.getAttribute('href')),
+            expect(linkElements).toHaveLength(2);
+            expect(linkElements.map(link => link.getAttribute('href'))).toEqual(
                 [`/${action}/1/show`, `/${action}/2/show`]
             );
             cleanup();
@@ -155,8 +152,8 @@ describe('<SingleFieldList />', () => {
         );
 
         const linkElements = queryAllByRole('link');
-        assert.equal(linkElements.length, 0);
-        assert.notEqual(queryByText('foo'), null);
-        assert.notEqual(queryByText('bar'), null);
+        expect(linkElements).toHaveLength(0);
+        expect(queryByText('foo')).not.toBeNull();
+        expect(queryByText('bar')).not.toBeNull();
     });
 });