var nthCheck = require(“./”),

assert = require("assert");

var invalid = [“-”, “asdf”, “2n+-0”, “2+0”, “- 1n”, “-1 n”];

function parseInvalid(){

invalid.forEach(function(formula){
        assert.throws(function(){
                        nthCheck.parse(formula);
                },
                SyntaxError,
                formula
        );
});

}

var valid = {

"1": [ 0, 1 ],
"2": [ 0, 2 ],
"3": [ 0, 3 ],
"5": [ 0, 5 ],
" 1 ": [ 0, 1 ],
" 5 ": [ 0, 5 ],
"+2n + 1": [ 2, 1 ],
"-1": [ 0, -1 ],
"-1n + 3": [ -1, 3 ],
"-1n+3": [ -1, 3 ],
"-n+2": [ -1, 2 ],
"-n+3": [ -1, 3 ],
"0n+3": [ 0, 3 ],
"1n": [ 1, 0 ],
"1n+0": [ 1, 0 ],
"2n": [ 2, 0 ],
"2n + 1": [ 2, 1 ],
"2n+1": [ 2, 1 ],
"3n": [ 3, 0 ],
"3n+0": [ 3, 0 ],
"3n+1": [ 3, 1 ],
"3n+2": [ 3, 2 ],
"3n+3": [ 3, 3 ],
"3n-1": [ 3, -1 ],
"3n-2": [ 3, -2 ],
"3n-3": [ 3, -3 ],
even: [ 2, 0 ],
n: [ 1, 0 ],
"n+2": [ 1, 2 ],
odd: [ 2, 1 ],

//surprisingly, neither sizzle, qwery or nwmatcher cover these cases
"-4n+13": [-4, 13],
"-2n + 12": [-2, 12]

};

function parseValid(){

Object.keys(valid).forEach(function(formula){
        assert.deepEqual(nthCheck.parse(formula), valid[formula], formula);
});

}

function testValid(){

Object.keys(valid).forEach(function(formula){
        testFormula(valid[formula], formula);
});

}

var valArray = Array.apply(null, Array(2e3)).map(function(_, i){return i;});

function testFormula(formula, name){

var filtered = valArray.filter(nthCheck.compile(formula)),
    iterated = stupidNth(formula);

try {
        assert.deepEqual(filtered, iterated, name);
} catch(e){
        e.expected = JSON.stringify(iterated) + " " + name;
        e.actual = JSON.stringify(filtered) + " " + name;
        throw e;
}

}

function stupidNth(formula, limit){

var a = formula[0],
    b = formula[1];

if(a === 0 && b > 0) return [b - 1];

//taken from qwery
return valArray.filter(function(val){
        for(var i = b, l = valArray.length; ((a > 0) ? (i <= l) : (i >= 1)); i += a){
                if(val === valArray[i - 1]) return true;
        }
});

}

process.stdout.write(“- parser”); process.stdout.write(“n - parse invalid:t”); parseInvalid(); process.stdout.write(“Xn - parse valid:t”); parseValid(); process.stdout.write(“Xn- check values: t”); testValid(); process.stdout.write(“Xn”);