message: [tests] Test route src and dest for normalized path
  Adding assertions for normalized routes.
diff: @@ -7,8 +7,6 @@ const { FileFsRef } = require('@vercel/build-utils');
  jest.setTimeout(ms('6m'));
  describe(`${__dirname.split(path.sep).pop()}`, () => {
  - afterEach(() => fs.remove(path.join(__dirname, 'yarn.lock')));
  -
  it('should normalize routes in build results output', async () => {
  const files = [
  'index.test.js',
  @@ -24,7 +22,7 @@ describe(`${__dirname.split(path.sep).pop()}`, () => {
  return filesMap;
  }, {});
  - const { output } = await build({
  + const { output, routes } = await build({
  config: {},
  entrypoint: 'package.json',
  files,
  @@ -44,5 +42,16 @@ describe(`${__dirname.split(path.sep).pop()}`, () => {
  path.join(pagesDir, `${page}.html`)
  );
  }
  +
  + for (const route of routes) {
  + if (typeof route.src === 'string') {
  + // src must start with a forward slash (or caret if a regex)
  + expect(route.src).toMatch(/^[/^]/);
  + }
  + if (typeof route.dest === 'string') {
  + // dest can be `/400` or `/.*` or `$0`, but not start with \
  + expect(route.dest).not.toMatch(/^\\/);
  + }
  + }
  });
  });
  