Test migration to jest by hand

Apparently using regular expressions is way easier.

test/percentile/percentile.js

@@ -0,0 +1,3 @@
+const percentile = (arr, val) =>
+100 * arr.reduce((acc, v) => acc + (v < val ? 1 : 0) + (v === val ? 0.5 : 0), 0) / arr.length;
+module.exports = percentile;

test/percentile/percentile.test.js

@@ -0,0 +1,9 @@
+const expect = require('expect');
+const percentile = require('./percentile.js');
+
+
+  test('percentile is a Function', () => {
+  expect(percentile).toBeInstanceOf(Function);
+});
+  t.equal(percentile([1, 2, 3, 4, 5, 6, 7, 8, 9, 10], 6), 55, "Uses the percentile formula to calculate how many numbers in the given array are less or equal to the given value.");
+