increaseTime.js

testRpc.increaseTime = function(secondsToJump, cb) {
    function send(method, params, callback) {
        if (typeof params == "function") {
            callback = params;
            params = [];
        }

        provider.sendAsync({
            jsonrpc: "2.0",
            method: method,
            params: params || [],
            id: new Date().getTime()
        }, callback);
    }

    var timestampBeforeJump;
    web3.eth.getBlock('latest', function(err, block){
        if(err) return cb(err)
        timestampBeforeJump = block.timestamp
        send("evm_increaseTime", [secondsToJump], function(err, result) {
            if (err) return cb(err);

            // Mine a block so new time is recorded.
            send("evm_mine", function(err, result) {
                if (err) return cb(err);

                web3.eth.getBlock('latest', function(err, block){
                    if(err) return cb(err)
                    console.log('block', block.timestamp)
                    var secondsJumped = block.timestamp - timestampBeforeJump;

                    // Somehow it jumps an extra 18 seconds, ish, when run inside the whole
                    // test suite. It might have something to do with when the before block
                    // runs and when the test runs. Likely the last block didn't occur for
                    // awhile.
                    console.log({secondsToJump, secondsJumped});
                    if(secondsJumped < secondsToJump) cb(Error('Testrpc time jump failed'));
                    cb()
                })
            })
        })
    })

};