refactor: add js-libp2p-switch to the libp2p codebase (#388)

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test/switch/constructor.spec.js

@@ -0,0 +1,15 @@
+/* eslint-env mocha */
+'use strict'
+
+const chai = require('chai')
+const dirtyChai = require('dirty-chai')
+const expect = chai.expect
+chai.use(dirtyChai)
+
+const Switch = require('libp2p-switch')
+
+describe('create Switch instance', () => {
+  it('throws on missing peerInfo', () => {
+    expect(() => new Switch()).to.throw(/You must provide a `peerInfo`/)
+  })
+})