fix: dns interceptor undefined function (#3958)

* fix: undefined function called

* test: easier test

Depends on PR #3956 being merged first.

Author: luddd3

lib/interceptor/dns.js

@@ -213,6 +213,10 @@ class DNSInstance {
     this.#records.set(origin.hostname, records)
   }
 
+  deleteRecords (origin) {
+    this.#records.delete(origin.hostname)
+  }
+
   getHandler (meta, opts) {
     return new DNSDispatchHandler(this, meta, opts)
   }
@@ -261,7 +265,7 @@ class DNSDispatchHandler extends DecoratorHandler {
         break
       }
       case 'ENOTFOUND':
-        this.#state.deleteRecord(this.#origin)
+        this.#state.deleteRecords(this.#origin)
       // eslint-disable-next-line no-fallthrough
       default:
         super.onResponseError(controller, err)

test/interceptors/dns.js

@@ -1732,6 +1732,57 @@ test('Should handle max cached items', async t => {
   t.equal(await response3.body.text(), 'hello world! (x2)')
 })
 
+test('Should handle ENOTFOUND response error', async t => {
+  t = tspl(t, { plan: 3 })
+  let lookupCounter = 0
+
+  const requestOptions = {
+    method: 'GET',
+    path: '/',
+    origin: 'http://localhost'
+  }
+
+  const client = new Agent().compose([
+    dns({
+      lookup (origin, opts, cb) {
+        lookupCounter++
+        if (lookupCounter === 1) {
+          const err = new Error('test error')
+          err.code = 'ENOTFOUND'
+          cb(err)
+        } else {
+          // Causes InformationalError
+          cb(null, [])
+        }
+      }
+    })
+  ])
+
+  after(async () => {
+    await client.close()
+  })
+
+  let error1
+  try {
+    await client.request(requestOptions)
+  } catch (err) {
+    error1 = err
+  }
+  t.equal(error1.code, 'ENOTFOUND')
+
+  // Test that the records in the dns interceptor were deleted after the
+  // previous request
+  let error2
+  try {
+    await client.request(requestOptions)
+  } catch (err) {
+    error2 = err
+  }
+  t.equal(error2.name, 'InformationalError')
+
+  t.equal(lookupCounter, 2)
+})
+
 test('#3937 - Handle host correctly', async t => {
   t = tspl(t, { plan: 10 })