feat(socket): propagate errors from destroy method (#1675)

Calling `destroy` on the the response, with an error, not correctly propagates through the socket and then the request object. This aligns with Node's native functionality. 

Fixes: #1669

lib/request_overrider.js

@@ -124,7 +124,7 @@ class InterceptedRequestHandler {
     this.response.socket = this.response.client = this.response.connection =
       req.socket
 
-    propagate(['timeout'], req.socket, req)
+    propagate(['error', 'timeout'], req.socket, req)
 
     req.write = (...args) => this.handleWrite(...args)
     req.end = (...args) => this.handleEnd(...args)

lib/socket.js

@@ -54,8 +54,12 @@ module.exports = class Socket extends EventEmitter {
     ).toString('base64')
   }
 
-  destroy() {
+  destroy(err) {
     this.destroyed = true
     this.readable = this.writable = false
+    if (err) {
+      this.emit('error', err)
+    }
+    return this
   }
 }

tests/test_destroy.js

@@ -0,0 +1,43 @@
+'use strict'
+
+const nock = require('..')
+const http = require('http')
+const { test } = require('tap')
+
+require('./cleanup_after_each')()
+
+test('req.destroy should emit error event if called with error', t => {
+  nock('http://example.test')
+    .get('/')
+    .reply(404)
+
+  http
+    .get('http://example.test/', res => {
+      if (res.statusCode !== 200) {
+        res.destroy(new Error('Response error'))
+      }
+    })
+    .once('error', err => {
+      t.type(err, Error)
+      t.equal(err.message, 'Response error')
+      t.end()
+    })
+})
+
+test('req.destroy should not emit error event if called without error', t => {
+  nock('http://example.test')
+    .get('/')
+    .reply(403)
+
+  http
+    .get('http://example.test/', res => {
+      if (res.statusCode === 403) {
+        res.destroy()
+      }
+
+      t.end()
+    })
+    .once('error', () => {
+      t.fail('should not emit error')
+    })
+})