The problem is in template-utils.js

var pattern_regex = new RegExp(pattern.replace(special_chars_regex, '$&').replace(token_regex, '(.+)'));

var matches = str.match(pattern_regex);

The pattern_regex evaluates to /(.+) (.+) (.+) ((.+))/g which splits on spaces in the assertionOutput.

/*
test > Prints 'hello world'

hello('hello world') == 'hello world' (test)

*/
hello = function(str){
return 'hello world';
};

Hello world doesn't even work!

If pattern_regex was /(.+) (.+) (("|')(.+)("|')|(.+)) ((.+))/g it would fix the spaces inside strings but it doesn't account for spaces in json.