feat: interface pubsub (#60)

* feat: interface pubsub

* chore: pubsub router tests

* chore: move pubsub abstractions from gossipsub

* chore: address review

* chore: revamp docs

* chore: add emit self tests to interface

* chore: refactor base tests

* chore: publish should only accept one topic per api call

* chore: normalize msg before emit

* chore: do not reset inbound stream

* chore: apply suggestions from code review

Co-authored-by: Jacob Heun <jacobheun@gmail.com>

* chore: address review

* fix: remove subscribe handler

* chore: remove bits from create peerId

Co-authored-by: Jacob Heun <jacobheun@gmail.com>

* chore: remove delay from topic validators tests

* chore: add event emitter information

* fix: topic validator docs

Co-authored-by: Jacob Heun <jacobheun@gmail.com>

test/pubsub/emit-self.spec.js

@@ -0,0 +1,78 @@
+/* eslint-env mocha */
+'use strict'
+
+const { expect } = require('aegir/utils/chai')
+
+const {
+  createPeerId,
+  mockRegistrar,
+  PubsubImplementation
+} = require('./utils')
+
+const uint8ArrayFromString = require('uint8arrays/from-string')
+
+const protocol = '/pubsub/1.0.0'
+const topic = 'foo'
+const data = uint8ArrayFromString('bar')
+const shouldNotHappen = (_) => expect.fail()
+
+describe('emitSelf', () => {
+  let pubsub
+
+  describe('enabled', () => {
+    before(async () => {
+      const peerId = await createPeerId()
+
+      pubsub = new PubsubImplementation(protocol, {
+        peerId,
+        registrar: mockRegistrar
+      }, { emitSelf: true })
+    })
+
+    before(() => {
+      pubsub.start()
+      pubsub.subscribe(topic)
+    })
+
+    after(() => {
+      pubsub.stop()
+    })
+
+    it('should emit to self on publish', () => {
+      const promise = new Promise((resolve) => pubsub.once(topic, resolve))
+
+      pubsub.publish(topic, data)
+
+      return promise
+    })
+  })
+
+  describe('disabled', () => {
+    before(async () => {
+      const peerId = await createPeerId()
+
+      pubsub = new PubsubImplementation(protocol, {
+        peerId,
+        registrar: mockRegistrar
+      }, { emitSelf: false })
+    })
+
+    before(() => {
+      pubsub.start()
+      pubsub.subscribe(topic)
+    })
+
+    after(() => {
+      pubsub.stop()
+    })
+
+    it('should not emit to self on publish', () => {
+      pubsub.once(topic, (m) => shouldNotHappen)
+
+      pubsub.publish(topic, data)
+
+      // Wait 1 second to guarantee that self is not noticed
+      return new Promise((resolve) => setTimeout(() => resolve(), 1000))
+    })
+  })
+})