message: chore: actually check the text in stderr to make sure that it's something that we don't expect
diff: @@ -445,9 +445,26 @@ async function testBackendStart(appDir: string, isPostgres: boolean) {
  });
  let successful = false;
  + const stdErrorHasErrors = (input: string) => {
  + const lines = input.split('\n').filter(Boolean);
  + return (
  + lines.filter(
  + l =>
  + !l.includes('Use of deprecated folder mapping') &&
  + !l.includes('Update this package.json to use a subpath') &&
  + !l.includes(
  + '(Use `node --trace-deprecation ...` to show where the warning was created)',
  + ),
  + ).length !== 0
  + );
  + };
  +
  try {
  - await waitFor(() => stdout.includes('Listening on ') || stderr !== '');
  + await waitFor(
  + () => stdout.includes('Listening on ') || stdErrorHasErrors(stderr),
  + );
  if (stderr !== '') {
  + print(`Expected stderr to be clean, got ${stderr}`);
  // Skipping the whole block
  throw new Error(stderr);
  }
  @@ -460,6 +477,7 @@ async function testBackendStart(appDir: string, isPostgres: boolean) {
  print('Entities fetched successfully');
  successful = true;
  } catch (error) {
  + print('');
  throw new Error(`Backend failed to startup: ${error}`);
  } finally {
  print('Stopping the child process');
  