Improve tests

Author: djhi

packages/ra-core/src/controller/list/ListBase.spec.tsx

@@ -168,6 +168,7 @@ describe('ListBase', () => {
     });
     it('should render nothing while loading if emptyWhileLoading is set to true', async () => {
         render(<EmptyWhileLoading />);
+        expect(screen.queryByText('Loading...')).toBeNull();
         expect(screen.queryByText('War and Peace')).toBeNull();
         fireEvent.click(screen.getByText('Resolve books loading'));
         await screen.findByText('War and Peace');

packages/ra-core/src/controller/list/ListBase.stories.tsx

@@ -493,15 +493,13 @@ export const EmptyWhileLoadingRender = () => {
                 resource="books"
                 perPage={5}
                 emptyWhileLoading
-                render={({ data }) => {
-                    return (
-                        <ul>
-                            {data.map((record: any) => (
-                                <li key={record.id}>{record.title}</li>
-                            ))}
-                        </ul>
-                    );
-                }}
+                render={({ data }) => (
+                    <ul>
+                        {data.map((record: any) => (
+                            <li key={record.id}>{record.title}</li>
+                        ))}
+                    </ul>
+                )}
             />
         </CoreAdminContext>
     );