revert: reapply "fix: throw if no conn encryption module provided (#665)"

This reapplies commit b621fbdfdc.

test/core/encryption.spec.js

@@ -0,0 +1,57 @@
+'use strict'
+/* eslint-env mocha */
+
+const chai = require('chai')
+chai.use(require('dirty-chai'))
+chai.use(require('chai-as-promised'))
+const { expect } = chai
+
+const Transport = require('libp2p-websockets')
+const { NOISE: Crypto } = require('libp2p-noise')
+
+const Libp2p = require('../../src')
+const { codes: ErrorCodes } = require('../../src/errors')
+const { createPeerId } = require('../utils/creators/peer')
+
+describe('Connection encryption configuration', () => {
+  let peerId
+
+  before(async () => {
+    [peerId] = await createPeerId()
+  })
+
+  it('is required', async () => {
+    const config = {
+      peerId,
+      modules: {
+        transport: [Transport]
+      }
+    }
+
+    await expect(Libp2p.create(config)).to.eventually.be.rejected()
+      .and.to.have.property('code', ErrorCodes.CONN_ENCRYPTION_REQUIRED)
+  })
+
+  it('is required and needs at least one module', async () => {
+    const config = {
+      peerId,
+      modules: {
+        transport: [Transport],
+        connEncryption: []
+      }
+    }
+    await expect(Libp2p.create(config)).to.eventually.be.rejected()
+      .and.to.have.property('code', ErrorCodes.CONN_ENCRYPTION_REQUIRED)
+  })
+
+  it('can be created', async () => {
+    const config = {
+      peerId,
+      modules: {
+        transport: [Transport],
+        connEncryption: [Crypto]
+      }
+    }
+    await Libp2p.create(config)
+  })
+})