old_contents: module.exports = function Action(input) {
    var type = input.type;
    var payload = input.payload;
  
    if (!type || !payload) {
      throw Error('Missing action data');
    }
  
    return input;
  };
  
new_contents: var SUPPORTED_ACTIONS = ['COMMIT', 'NOTIFY', 'ASSIGN_USERS_TO_PULL_REQUEST', 'UNASSIGN_USERS_FROM_PULL_REQUEST'];
  
  module.exports = function Action(input) {
    var type = input.type;
    var payload = input.payload;
  
    if (!type || !payload) {
      throw Error('Missing action data');
    } else if (SUPPORTED_ACTIONS.indexOf(type) === -1) {
      throw Error('Unsupported action: ' + type);
    }
  
    return input;
  };
  
subject: add action validation