Test migration to jest by hand

Apparently using regular expressions is way easier.

test/tail/tail.js

@@ -0,0 +1,2 @@
+const tail = arr => (arr.length > 1 ? arr.slice(1) : arr);
+module.exports = tail;

test/tail/tail.test.js

@@ -0,0 +1,10 @@
+const expect = require('expect');
+const tail = require('./tail.js');
+
+
+  test('tail is a Function', () => {
+  expect(tail).toBeInstanceOf(Function);
+});
+  t.deepEqual(tail([1, 2, 3]), [2, 3], "Returns tail");
+  t.deepEqual(tail([1]), [1], "Returns tail");
+