Test migration to jest by hand

Apparently using regular expressions is way easier.

test/elo/elo.js

@@ -0,0 +1,19 @@
+const elo = ([...ratings], kFactor = 32, selfRating) => {
+const [a, b] = ratings;
+const expectedScore = (self, opponent) => 1 / (1 + 10 ** ((opponent - self) / 400));
+const newRating = (rating, i) =>
+(selfRating || rating) + kFactor * (i - expectedScore(i ? a : b, i ? b : a));
+if (ratings.length === 2) {
+return [newRating(a, 1), newRating(b, 0)];
+} else {
+for (let i = 0; i < ratings.length; i++) {
+let j = i;
+while (j < ratings.length - 1) {
+[ratings[i], ratings[j + 1]] = elo([ratings[i], ratings[j + 1]], kFactor);
+j++;
+}
+}
+}
+return ratings;
+};
+module.exports = elo;

test/elo/elo.test.js

@@ -0,0 +1,11 @@
+const expect = require('expect');
+const elo = require('./elo.js');
+
+
+  test('elo is a Function', () => {
+  expect(elo).toBeInstanceOf(Function);
+});
+  t.deepEqual(elo([1200, 1200]), [1216, 1184], "Standard 1v1s");
+  t.deepEqual(elo([1200, 1200], 64), [1232, 1168]), "Standard 1v1s";
+  t.deepEqual(elo([1200, 1200, 1200, 1200]).map(Math.round), [1246, 1215, 1185, 1154], "4 player FFA, all same rank");
+