Edit in JSFiddle

"use strict";

var Primes = (function() {

  var isPrime = function(value) {
    for (var i = 2; i < value; i++) {
      if (value % i === 0) {
        return false;
      }
    }
    return value > 1;
  };

  var areAllPrimes = function(arr) {
    var result = false;
    result = arr.every(isPrime);

    return result;
  };

  return {
    areAllPrimes: areAllPrimes
  }
}());

var Tests = (function() {

  var results = {
    total: 0,
    bad: 0
  };

  var test = function(arr, expected) {
    results.total++;
    var result = Primes.areAllPrimes(arr);
    if (result !== expected) {
      results.bad++;
      console.log(arr + " expected " + expected + ", but was " + result);
    }
  }

  test([1, 2, 3], false);
  test([2, 3, 65537], true);
  test([7, 5, 11], true);
  test([23, 11, 37], true);
  test([12, 7, 5], false);
  test([10, 100, 1000], false);

  console.log("Of " + results.total + " tests, " + results.bad + " failed, " + (results.total - results.bad) + " passed.");

}());