Test migration to jest by hand

Apparently using regular expressions is way easier.

test/sum/sum.js

@@ -0,0 +1,2 @@
+const sum = (...arr) => [...arr].reduce((acc, val) => acc + val, 0);
+module.exports = sum;

test/sum/sum.test.js

@@ -0,0 +1,9 @@
+const expect = require('expect');
+const sum = require('./sum.js');
+
+
+  test('sum is a Function', () => {
+  expect(sum).toBeInstanceOf(Function);
+});
+  t.equal(sum(...[1, 2, 3, 4]), 10, "Returns the sum of two or more numbers/arrays.");
+