Migrated tests to jest

Used jest-codemods to migrate, will have to pass everything by hand before we can merge.

test/when/when.test.js

@@ -1,18 +0,0 @@
-const test = require('tape');
-const when = require('./when.js');
-
-test('Testing when', (t) => {
-  //For more information on all the methods supported by tape
-  //Please go to https://github.com/substack/tape
-  t.true(typeof when === 'function', 'when is a Function');
-
-  const doubleEvenNumbers = when(
-    (x) => x % 2 === 0,
-    (x) => x * 2
-  );
-
-  t.true(doubleEvenNumbers(2) === 4);
-  t.true(doubleEvenNumbers(1) === 1);
-
-  t.end();
-});