message: Give file in test a file extension.
diff: @@ -465,7 +465,7 @@ suite('Analyzer', () => {
  });
  test(`warns for files that don't exist`, async () => {
  - const url = '/static/does_not_exist';
  + const url = '/static/does_not_exist.html';
  const analysis = await analyzer.analyze([url]);
  const result = analysis.getDocument(url);
  if (result.successful) {
  