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

Co-authored-by: Alan Shaw <alan.shaw@protocol.ai>
Co-authored-by: Alan Shaw <alan@tableflip.io>
Co-authored-by: Arnaud <arnaud.valensi@gmail.com>
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Co-authored-by: Hugo Dias <hugomrdias@gmail.com>
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Co-authored-by: ᴠɪᴄᴛᴏʀ ʙᴊᴇʟᴋʜᴏʟᴍ <victorbjelkholm@gmail.com>

test/switch/limit-dialer.node.js

@@ -0,0 +1,93 @@
+/* eslint-env mocha */
+'use strict'
+
+const chai = require('chai')
+chai.use(require('dirty-chai'))
+chai.use(require('chai-checkmark'))
+const expect = chai.expect
+const multiaddr = require('multiaddr')
+const pull = require('pull-stream')
+const setImmediate = require('async/setImmediate')
+
+const LimitDialer = require('libp2p-switch/limit-dialer')
+const utils = require('./utils')
+
+describe('LimitDialer', () => {
+  let peers
+
+  before((done) => {
+    utils.createInfos(5, (err, infos) => {
+      if (err) {
+        return done(err)
+      }
+      peers = infos
+
+      peers.forEach((peer, i) => {
+        peer.multiaddrs.add(multiaddr(`/ip4/191.0.0.1/tcp/123${i}`))
+        peer.multiaddrs.add(multiaddr(`/ip4/192.168.0.1/tcp/923${i}`))
+        peer.multiaddrs.add(multiaddr(`/ip4/193.168.0.99/tcp/923${i}`))
+      })
+      done()
+    })
+  })
+
+  it('all failing', (done) => {
+    const dialer = new LimitDialer(2, 10)
+    const error = new Error('fail')
+    // mock transport
+    const t1 = {
+      dial (addr, cb) {
+        setTimeout(() => cb(error), 1)
+        return {}
+      }
+    }
+
+    dialer.dialMany(peers[0].id, t1, peers[0].multiaddrs.toArray(), (err, conn) => {
+      expect(err).to.exist()
+      expect(err).to.eql([error, error, error])
+      expect(conn).to.not.exist()
+      done()
+    })
+  })
+
+  it('two success', (done) => {
+    const dialer = new LimitDialer(2, 10)
+
+    // mock transport
+    const t1 = {
+      dial (addr, cb) {
+        const as = addr.toString()
+        if (as.match(/191/)) {
+          setImmediate(() => cb(new Error('fail')))
+          return null
+        } else if (as.match(/192/)) {
+          setTimeout(cb, 2)
+          return {
+            source: pull.values([1]),
+            sink: pull.drain()
+          }
+        } else if (as.match(/193/)) {
+          setTimeout(cb, 8)
+          return {
+            source: pull.values([2]),
+            sink: pull.drain()
+          }
+        }
+      }
+    }
+
+    dialer.dialMany(peers[0].id, t1, peers[0].multiaddrs.toArray(), (err, success) => {
+      const conn = success.conn
+      expect(success.multiaddr.toString()).to.equal('/ip4/192.168.0.1/tcp/9230')
+      expect(err).to.not.exist()
+      pull(
+        conn,
+        pull.collect((err, res) => {
+          expect(err).to.not.exist()
+          expect(res).to.be.eql([1])
+          done()
+        })
+      )
+    })
+  })
+})