Migrated tests to jest

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

test6/URLJoin/URLJoin.js

@@ -0,0 +1,10 @@
+const URLJoin = (...args) =>
+args
+.join('/')
+.replace(/[\/]+/g, '/')
+.replace(/^(.+):\//, '$1://')
+.replace(/^file:/, 'file:/')
+.replace(/\/(\?|&|#[^!])/g, '$1')
+.replace(/\?/g, '&')
+.replace('&', '?');
+module.exports = URLJoin;