Migrated tests to jest

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

test6/when/when.js

@@ -0,0 +1,2 @@
+const when = (pred, whenTrue) => x => (pred(x) ? whenTrue(x) : x);
+module.exports = when;

test6/when/when.test.js

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+const expect = require('expect');
+const when = require('./when.js');
+
+test('Testing when', () => {
+  //For more information on all the methods supported by tape
+  //Please go to https://github.com/substack/tape
+  expect(typeof when === 'function').toBeTruthy();
+
+  const doubleEvenNumbers = when(
+    (x) => x % 2 === 0,
+    (x) => x * 2
+  );
+
+  expect(doubleEvenNumbers(2) === 4).toBeTruthy();
+  expect(doubleEvenNumbers(1) === 1).toBeTruthy();
+});