Test migration to jest by hand

Apparently using regular expressions is way easier.

test/httpPost/httpPost.js

@@ -0,0 +1,9 @@
+const httpPost = (url, data, callback, err = console.error) => {
+const request = new XMLHttpRequest();
+request.open('POST', url, true);
+request.setRequestHeader('Content-type', 'application/json; charset=utf-8');
+request.onload = () => callback(request.responseText);
+request.onerror = () => err(request);
+request.send(data);
+};
+module.exports = httpPost;