function parseNoErrors(...lines) {
  const result = parser.parseText(lines.join('\n'), 'testfile');
  if (result.errors.length) {
    throw new Error(
        'Had errors: ' + result.errors.map(e => e.toString()).join('\n'));
  }
  return result.dependencies;
}
@param {...string} lines
@return {!Array<!depGraph.Dependency>}