How to use casperjs evaluate to diff 2 strings and assert - regex

Question

I have a simple test that checks to see a user's quota correctly changes after they upload a file.
casper.then(function() {
quota_begin = this.evaluate(function() {
return document.querySelector('.storage_used p').textContent;
});
});
casper.then(function() {
common.ACTIONS.uploadFile(casper);
});
casper.then(function() {
quota_changed = this.evaluate(function() {
return document.querySelector('.storage_used p').textContent;
});
this.echo('Storage quota change: ' + quota_begin + ' => ' + quota_changed);
});
That last echo's output gives me:
Storage quota change: Upload quota 0B of 1GB used => Upload quota 192 KB of 1GB used
I'd like to include an assert in the test that fails when quota_begin and quota_changed do not actually change.
Something like:
test.assert(parseFloat(quota_changed) > parseFloat(quota_begin), "Quota was increased by file");
(doesn't work)
Is there an easy way to assert a diff on the two? regex?

Answer 1

Write a simple function to parse used bytes from that string will do that task:
function get_used_bytes(input) {
var unit_dict = {'B':1,'KB':1024,'MB':1024*1024,'GB':1024*1024*1024}
var ret = /Upload quota ([\d.]+)(\S+) of ([\d.]+)(\S+) used/g.exec(input)
return ret[1] * unit_dict[ret[2]]
}
// get_used_bytes("Upload quota 192KB of 1GB used")
// 196608
test.assert(get_used_bytes(quota_changed) > get_used_bytes(quota_begin), "Quota was increased by file");