Home spun tests for FP deduping thing for Tim

dedupeTests.js

var _ = require('underscore');

// getDupeList([Tweet]) -> { String : [Int] }
// runs in O(n+m) where n is # tweets, m is # dupes
function getDupeList(ts){
  var tts =_.chain(ts)
        .map(function(t,i){ return _.extend(t, { i: i });})
        .groupBy(function(tt){ return tt.id_str;})
        .value();
  return _.chain(tts)
    .keys()
    .filter(function(k){ return tts[k].length > 1; })
    .map(function(kk){
      return [kk, _.map(tts[kk], function(tt){
        return tt.i;})];})
    .object()
    .value();
}

//test getDupeList
(function(){

  var fn = getDupeList;
  var purpose = "getDupeList() finds the indices of dupes";

  testSimple();
  testNoDupes();
  testEmpty();

  // testSimple() -> Void
  function testSimple(){
    var input  = [
      { _id: 1, id_str: "123"},
      { _id: 2, id_str: "123"},
      { _id: 3, id_str: "456"},
      { _id: 4, id_str: "123"},
      { _id: 5, id_str: "456"},
      { _id: 6, id_str: "789"}
    ];
    var expected = {
      "123": [0,1,3],
      "456": [2,4] };
    test(fn(input),expected,purpose + "\n with a list that has dupes");
  }

  // testSimple() -> Void
  function testNoDupes(){
    var input = [
      { _id: 1, id_str: "123"},
      { _id: 2, id_str: "456"},
      { _id: 3, id_str: "789"}
    ];
    var expected = {};
    test(fn(input),expected,purpose + "\n with a list with no dupes");
  }

  // testSimple() -> Void
  function testEmpty(){
    var input = [], expected = {};
    test(fn(input),expected,purpose + "\n with an empty list");
  }

})();

// test(Any,Any,String) -> Void
// prints "PASSING" if actual deepEquals expected
// prints "FAILING" and a var dump if actual doesn't deepEqual expected
function test(actual,expected,purpose){
  if (_.isEqual(actual,expected)){ console.log("PASSING: ", purpose); }
  else {
    console.log("FAILED: ", purpose);
    console.log("-- expected: ", expected);
    console.log("-- actual: ", actual);
  }
}