code: function increaseProviderTime(provider, time, callback) {
    if (typeof time !== 'number') {
      callback('error while increasing TestRPC provider time, time value must be a number.', null);
      return;
    }
  
    provider.sendAsync({
      method: 'evm_increaseTime',
      params: [time],
    }, (increaseTimeError) => {
      if (increaseTimeError) {
        callback(`error while increasing TestRPC provider time: ${JSON.stringify(increaseTimeError)}`, null);
      } else {
        provider.sendAsync({
          method: 'evm_mine',
        }, (mineError) => {
          if (mineError) {
            callback(`while mining block to increase time on TestRPC provider: ${JSON.stringify(mineError)}`, null);
          } else {
            callback(null, true);
          }
        });
      }
    });
  }
docs: increase the testrpc provider time by a specific amount, then mine