// `evm_` ONLY works in the testrpc `development` env
// `evm_mine` is not a standard web3/eth call
function advanceBlock() {
  return new Promise(resolve => {
    web3.currentProvider.sendAsync({
      method: "evm_mine",
      jsonrpc: "2.0",
      id: new Date().getTime()
    }, function (error, result) {
      if (error) {
        console.log('Could not advance block :: ', error)
      } else {
        console.log('Advance to block :: ', web3.eth.blockNumber, result.id);
        resolve(result);
      }
    });
  });
}


// usage
  it("should have owner", function(done) {
    MyContract.deployed().then(function(instance) {
      return instance.owner.call();
    }).then(function(results) {
      assert.equal(results, accounts[0], "does not match creater etherbase/accounts[0]");

      // => block 1
      return advanceBlock();
    }).then(function(results) {
      // check id of sendAsync
      //       `results.id`
      done();
    }).catch(done);
  });