Converts a Koa app into a supertest compatible agent instance.
npm install supertest-koa-agent --save-dev
var agent = require('supertest-koa-agent');
var Koa = require('koa')
var app = new Koa()
agent(app)
app: (Application)
Koa application instance.
(Object)
Supertest agent instance.
SEE: contributing.md