Test migration to jest by hand

Apparently using regular expressions is way easier.

test/unfold/unfold.test.js

@@ -0,0 +1,11 @@
+const expect = require('expect');
+const unfold = require('./unfold.js');
+
+
+  test('unfold is a Function', () => {
+  expect(unfold).toBeInstanceOf(Function);
+});
+  var f = n => (n > 50 ? false : [-n, n + 10]);
+  t.deepEqual(unfold(f, 10), [-10, -20, -30, -40, -50], 'Works with a given function, producing an array');
+  
+