test: mock dns lookup function in parallel tests

test/common/README.md

@@ -419,7 +419,26 @@ called before the callback is invoked.
 
 ## DNS Module
 
-The `DNS` module provides a naïve DNS parser/serializer.
+The `DNS` module provides utilities related to the `dns` built-in module.
+
+### errorLookupMock(code, syscall)
+
+* `code` [<String>] Defaults to `dns.mockedErrorCode`.
+* `syscall` [<String>] Defaults to `dns.mockedSysCall`.
+* return [<Function>]
+
+
+A mock for the `lookup` option of `net.connect()` that would result in an error
+with the `code` and the `syscall` specified. Returns a function that has the
+same signature as `dns.lookup()`.
+
+### mockedErrorCode
+
+The default `code` of errors generated by `errorLookupMock`.
+
+### mockedSysCall
+
+The default `syscall` of errors generated by `errorLookupMock`.
 
 ### readDomainFromPacket(buffer, offset)
 

test/common/dns.js

@@ -1,8 +1,6 @@
 /* eslint-disable required-modules */
 'use strict';
 
-// Naïve DNS parser/serializer.
-
 const assert = require('assert');
 const os = require('os');
 
@@ -22,6 +20,8 @@ const classes = {
   IN: 1
 };
 
+// Naïve DNS parser/serializer.
+
 function readDomainFromPacket(buffer, offset) {
   assert.ok(offset < buffer.length);
   const length = buffer[offset];
@@ -287,6 +287,26 @@ function writeDNSPacket(parsed) {
   }));
 }
 
+const mockedErrorCode = 'ENOTFOUND';
+const mockedSysCall = 'getaddrinfo';
+
+function errorLookupMock(code = mockedErrorCode, syscall = mockedSysCall) {
+  return function lookupWithError(host, dnsopts, cb) {
+    const err = new Error(`${syscall} ${code} ${host}`);
+    err.code = code;
+    err.errno = code;
+    err.syscall = syscall;
+    err.hostname = host;
+    cb(err);
+  };
+}
+
 module.exports = {
-  types, classes, writeDNSPacket, parseDNSPacket
+  types,
+  classes,
+  writeDNSPacket,
+  parseDNSPacket,
+  errorLookupMock,
+  mockedErrorCode,
+  mockedSysCall
 };

test/parallel/test-http-client-req-error-dont-double-fire.js

@@ -1,11 +1,21 @@
 'use strict';
+
+// This tests that the error emitted on the socket does
+// not get fired again when the 'error' event handler throws
+// an error.
+
 const assert = require('assert');
 const http = require('http');
 const common = require('../common');
+const { addresses } = require('../common/internet');
+const { errorLookupMock } = require('../common/dns');
+
+const host = addresses.INVALID_HOST;
 
-// Invalid hostname as per https://tools.ietf.org/html/rfc2606#section-2
-const host = 'this.hostname.is.invalid';
-const req = http.get({ host });
+const req = http.get({
+  host,
+  lookup: common.mustCall(errorLookupMock())
+});
 const err = new Error('mock unexpected code error');
 req.on('error', common.mustCall(() => {
   throw err;

test/parallel/test-net-better-error-messages-port-hostname.js

@@ -1,21 +1,30 @@
 'use strict';
+
+// This tests that the error thrown from net.createConnection
+// comes with host and port properties.
+// See https://github.com/nodejs/node-v0.x-archive/issues/7005
+
 const common = require('../common');
 const net = require('net');
 const assert = require('assert');
 
+const { addresses } = require('../common/internet');
+const {
+  errorLookupMock,
+  mockedErrorCode
+} = require('../common/dns');
+
 // Using port 0 as hostname used is already invalid.
-const c = net.createConnection(0, 'this.hostname.is.invalid');
+const c = net.createConnection({
+  port: 0,
+  host: addresses.INVALID_HOST,
+  lookup: common.mustCall(errorLookupMock())
+});
 
 c.on('connect', common.mustNotCall());
 
 c.on('error', common.mustCall(function(e) {
-  // If Name Service Switch is available on the operating system then it
-  // might be configured differently (/etc/nsswitch.conf).
-  // If the system is configured with no dns the error code will be EAI_AGAIN,
-  // but if there are more services after the dns entry, for example some
-  // linux distributions ship a myhostname service by default which would
-  // still produce the ENOTFOUND error.
-  assert.ok(e.code === 'ENOTFOUND' || e.code === 'EAI_AGAIN');
+  assert.strictEqual(e.code, mockedErrorCode);
   assert.strictEqual(e.port, 0);
-  assert.strictEqual(e.hostname, 'this.hostname.is.invalid');
+  assert.strictEqual(e.hostname, addresses.INVALID_HOST);
 }));

test/parallel/test-net-connect-immediate-finish.js

@@ -20,28 +20,35 @@
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
 'use strict';
+
+// This tests that if the socket is still in the 'connecting' state
+// when the user calls socket.end() ('finish'), the socket would emit
+// 'connect' and defer the handling until the 'connect' event is handled.
+
 const common = require('../common');
 const assert = require('assert');
 const net = require('net');
 
+const { addresses } = require('../common/internet');
+const {
+  errorLookupMock,
+  mockedErrorCode,
+  mockedSysCall
+} = require('../common/dns');
+
 const client = net.connect({
-  host: 'this.hostname.is.invalid',
-  port: common.PORT
+  host: addresses.INVALID_HOST,
+  port: common.PORT,
+  lookup: common.mustCall(errorLookupMock())
 });
 
 client.once('error', common.mustCall((err) => {
   assert(err);
   assert.strictEqual(err.code, err.errno);
-  // If Name Service Switch is available on the operating system then it
-  // might be configured differently (/etc/nsswitch.conf).
-  // If the system is configured with no dns the error code will be EAI_AGAIN,
-  // but if there are more services after the dns entry, for example some
-  // linux distributions ship a myhostname service by default which would
-  // still produce the ENOTFOUND error.
-  assert.ok(err.code === 'ENOTFOUND' || err.code === 'EAI_AGAIN');
+  assert.strictEqual(err.code, mockedErrorCode);
   assert.strictEqual(err.host, err.hostname);
-  assert.strictEqual(err.host, 'this.hostname.is.invalid');
-  assert.strictEqual(err.syscall, 'getaddrinfo');
+  assert.strictEqual(err.host, addresses.INVALID_HOST);
+  assert.strictEqual(err.syscall, mockedSysCall);
 }));
 
 client.end();