Test migration to jest by hand

Apparently using regular expressions is way easier.

test/counter/counter.test.js

@@ -1,8 +1,8 @@
 const expect = require('expect');
 const counter = require('./counter.js');
 
-test('Testing counter', () => {
-  //For more information on all the methods supported by tape
-  //Please go to https://github.com/substack/tape
-  expect(typeof counter === 'function').toBeTruthy();
-});
+
+  test('counter is a Function', () => {
+  expect(counter).toBeInstanceOf(Function);
+});
+