9 files changed, 372 insertions, 0 deletions
diff --git a/test/common/snapshot.js b/test/common/snapshot.js
new file mode 100644
index 0000000000..97367c0565
--- /dev/null
+++ b/test/common/snapshot.js
@@ -0,0 +1,66 @@
+'use strict';
+
+const tmpdir = require('../common/tmpdir');
+const { spawnSync } = require('child_process');
+const path = require('path');
+const fs = require('fs');
+const assert = require('assert');
+
+function buildSnapshot(entry, env) {
+  const child = spawnSync(process.execPath, [
+    '--snapshot-blob',
+    path.join(tmpdir.path, 'snapshot.blob'),
+    '--build-snapshot',
+    entry,
+  ], {
+    cwd: tmpdir.path,
+    env: {
+      ...process.env,
+      ...env,
+    },
+  });
+
+  const stderr = child.stderr.toString();
+  const stdout = child.stdout.toString();
+  console.log('[stderr]');
+  console.log(stderr);
+  console.log('[stdout]');
+  console.log(stdout);
+
+  assert.strictEqual(child.status, 0);
+
+  const stats = fs.statSync(path.join(tmpdir.path, 'snapshot.blob'));
+  assert(stats.isFile());
+
+  return { child, stderr, stdout };
+}
+
+function runWithSnapshot(entry, env) {
+  const args = ['--snapshot-blob', path.join(tmpdir.path, 'snapshot.blob')];
+  if (entry !== undefined) {
+    args.push(entry);
+  }
+  const child = spawnSync(process.execPath, args, {
+    cwd: tmpdir.path,
+    env: {
+      ...process.env,
+      ...env,
+    }
+  });
+
+  const stderr = child.stderr.toString();
+  const stdout = child.stdout.toString();
+  console.log('[stderr]');
+  console.log(stderr);
+  console.log('[stdout]');
+  console.log(stdout);
+
+  assert.strictEqual(child.status, 0);
+
+  return { child, stderr, stdout };
+}
+
+module.exports = {
+  buildSnapshot,
+  runWithSnapshot,
+};
diff --git a/test/fixtures/snapshot/dns-lookup.js b/test/fixtures/snapshot/dns-lookup.js
new file mode 100644
index 0000000000..773b508f7c
--- /dev/null
+++ b/test/fixtures/snapshot/dns-lookup.js
@@ -0,0 +1,39 @@
+'use strict';
+const dns = require('dns');
+const assert = require('assert');
+
+assert(process.env.NODE_TEST_HOST);
+
+const {
+  setDeserializeMainFunction,
+} = require('v8').startupSnapshot;
+
+function onError(err) {
+  console.error('error:', err);
+}
+
+function onLookup(address, family) {
+  console.log(`address: ${JSON.stringify(address)}`);
+  console.log(`family: ${JSON.stringify(family)}`);
+}
+
+function query() {
+  const host = process.env.NODE_TEST_HOST;
+  if (process.env.NODE_TEST_PROMISE === 'true') {
+    dns.promises.lookup(host, { family: 4 }).then(
+      ({address, family}) => onLookup(address, family),
+      onError);
+  } else {
+    dns.lookup(host, { family: 4 }, (err, address, family) => {
+      if (err) {
+        onError(err);
+      } else {
+        onLookup(address, family);
+      }
+    });
+  }
+}
+
+query();
+
+setDeserializeMainFunction(query);
diff --git a/test/fixtures/snapshot/dns-resolve.js b/test/fixtures/snapshot/dns-resolve.js
new file mode 100644
index 0000000000..6a776f2970
--- /dev/null
+++ b/test/fixtures/snapshot/dns-resolve.js
@@ -0,0 +1,59 @@
+'use strict';
+const dns = require('dns');
+const assert = require('assert');
+
+assert(process.env.NODE_TEST_HOST);
+
+const {
+  setDeserializeMainFunction,
+} = require('v8').startupSnapshot;
+
+function onError(err) {
+  console.error('error:', err);
+}
+
+function onResolve(addresses) {
+  console.log(`addresses: ${JSON.stringify(addresses)}`);
+}
+
+function onReverse(hostnames) {
+  console.log(`hostnames: ${JSON.stringify(hostnames)}`);
+}
+
+function query() {
+  if (process.env.NODE_TEST_DNS) {
+    dns.setServers([process.env.NODE_TEST_DNS])
+  }
+
+  const host = process.env.NODE_TEST_HOST;
+  if (process.env.NODE_TEST_PROMISE === 'true') {
+    dns.promises.resolve4(host).then(onResolve, onError);
+  } else {
+    dns.resolve4(host, (err, addresses) => {
+      if (err) {
+        onError(err);
+      } else {
+        onResolve(addresses);
+      }
+    });
+  }
+
+  const ip = process.env.NODE_TEST_IP;
+  if (ip) {
+    if (process.env.NODE_TEST_PROMISE === 'true') {
+      dns.promises.reverse(ip).then(onReverse, onError);
+    } else {
+      dns.reverse(ip, (err, hostnames) => {
+        if (err) {
+          onError(err);
+        } else {
+          onReverse(hostnames);
+        }
+      });
+    }
+  }
+}
+
+query();
+
+setDeserializeMainFunction(query);
diff --git a/test/internet/test-snapshot-dns-lookup.js b/test/internet/test-snapshot-dns-lookup.js
new file mode 100644
index 0000000000..842e73e056
--- /dev/null
+++ b/test/internet/test-snapshot-dns-lookup.js
@@ -0,0 +1,34 @@
+'use strict';
+
+// This tests support for the dns module in snapshot.
+
+require('../common');
+const assert = require('assert');
+const tmpdir = require('../common/tmpdir');
+const fixtures = require('../common/fixtures');
+const { buildSnapshot, runWithSnapshot } = require('../common/snapshot');
+const {
+  addresses: { INET4_HOST },
+} = require('../common/internet');
+
+const entry = fixtures.path('snapshot', 'dns-lookup.js');
+const env = {
+  NODE_TEST_HOST: INET4_HOST,
+  NODE_TEST_PROMISE: 'false',
+};
+
+tmpdir.refresh();
+function checkOutput(stderr, stdout) {
+  assert(stdout.match(stdout, /address: "\d+\.\d+\.\d+\.\d+"/));
+  assert(stdout.match(stdout, /family: 4/));
+  assert.strictEqual(stdout.trim().split('\n').length, 2);
+}
+{
+  const { stderr, stdout } = buildSnapshot(entry, env);
+  checkOutput(stderr, stdout);
+}
+
+{
+  const { stderr, stdout } = runWithSnapshot(entry, env);
+  checkOutput(stderr, stdout);
+}
diff --git a/test/internet/test-snapshot-dns-resolve.js b/test/internet/test-snapshot-dns-resolve.js
new file mode 100644
index 0000000000..6efea9b4f7
--- /dev/null
+++ b/test/internet/test-snapshot-dns-resolve.js
@@ -0,0 +1,36 @@
+'use strict';
+
+// This tests support for the dns module in snapshot.
+
+require('../common');
+const assert = require('assert');
+const tmpdir = require('../common/tmpdir');
+const fixtures = require('../common/fixtures');
+const { buildSnapshot, runWithSnapshot } = require('../common/snapshot');
+const {
+  addresses: { DNS4_SERVER, INET4_IP, INET4_HOST },
+} = require('../common/internet');
+
+const entry = fixtures.path('snapshot', 'dns-resolve.js');
+const env = {
+  NODE_TEST_IP: INET4_IP,
+  NODE_TEST_HOST: INET4_HOST,
+  NODE_TEST_DNS: DNS4_SERVER,
+  NODE_TEST_PROMISE: 'false',
+};
+
+tmpdir.refresh();
+function checkOutput(stderr, stdout) {
+  assert(stdout.includes('hostnames: ['));
+  assert(stdout.includes('addresses: ['));
+  assert.strictEqual(stdout.trim().split('\n').length, 2);
+}
+{
+  const { stderr, stdout } = buildSnapshot(entry, env);
+  checkOutput(stderr, stdout);
+}
+
+{
+  const { stderr, stdout } = runWithSnapshot(entry, env);
+  checkOutput(stderr, stdout);
+}
diff --git a/test/parallel/test-snapshot-dns-lookup-localhost-promise.js b/test/parallel/test-snapshot-dns-lookup-localhost-promise.js
new file mode 100644
index 0000000000..d19488a716
--- /dev/null
+++ b/test/parallel/test-snapshot-dns-lookup-localhost-promise.js
@@ -0,0 +1,35 @@
+'use strict';
+
+// This tests support for the dns module in snapshot.
+
+require('../common');
+const assert = require('assert');
+const tmpdir = require('../common/tmpdir');
+const fixtures = require('../common/fixtures');
+const { buildSnapshot, runWithSnapshot } = require('../common/snapshot');
+
+const entry = fixtures.path('snapshot', 'dns-lookup.js');
+const env = {
+  NODE_TEST_HOST: 'localhost',
+  NODE_TEST_PROMISE: 'true',
+};
+
+tmpdir.refresh();
+function checkOutput(stderr, stdout) {
+  // We allow failures as it's not always possible to resolve localhost.
+  // Functional tests are done in test/internet instead.
+  if (!stderr.startsWith('error:')) {
+    assert(stdout.match(stdout, /address: "\d+\.\d+\.\d+\.\d+"/));
+    assert(stdout.match(stdout, /family: 4/));
+    assert.strictEqual(stdout.trim().split('\n').length, 2);
+  }
+}
+{
+  const { stderr, stdout } = buildSnapshot(entry, env);
+  checkOutput(stderr, stdout);
+}
+
+{
+  const { stderr, stdout } = runWithSnapshot(entry, env);
+  checkOutput(stderr, stdout);
+}
diff --git a/test/parallel/test-snapshot-dns-lookup-localhost.js b/test/parallel/test-snapshot-dns-lookup-localhost.js
new file mode 100644
index 0000000000..af00480bcc
--- /dev/null
+++ b/test/parallel/test-snapshot-dns-lookup-localhost.js
@@ -0,0 +1,35 @@
+'use strict';
+
+// This tests support for the dns module in snapshot.
+
+require('../common');
+const assert = require('assert');
+const tmpdir = require('../common/tmpdir');
+const fixtures = require('../common/fixtures');
+const { buildSnapshot, runWithSnapshot } = require('../common/snapshot');
+
+const entry = fixtures.path('snapshot', 'dns-lookup.js');
+const env = {
+  NODE_TEST_HOST: 'localhost',
+  NODE_TEST_PROMISE: 'false',
+};
+
+tmpdir.refresh();
+function checkOutput(stderr, stdout) {
+  // We allow failures as it's not always possible to resolve localhost.
+  // Functional tests are done in test/internet instead.
+  if (!stderr.startsWith('error:')) {
+    assert(stdout.match(stdout, /address: "\d+\.\d+\.\d+\.\d+"/));
+    assert(stdout.match(stdout, /family: 4/));
+    assert.strictEqual(stdout.trim().split('\n').length, 2);
+  }
+}
+{
+  const { stderr, stdout } = buildSnapshot(entry, env);
+  checkOutput(stderr, stdout);
+}
+
+{
+  const { stderr, stdout } = runWithSnapshot(entry, env);
+  checkOutput(stderr, stdout);
+}
diff --git a/test/parallel/test-snapshot-dns-resolve-localhost-promise.js b/test/parallel/test-snapshot-dns-resolve-localhost-promise.js
new file mode 100644
index 0000000000..cca86007f1
--- /dev/null
+++ b/test/parallel/test-snapshot-dns-resolve-localhost-promise.js
@@ -0,0 +1,34 @@
+'use strict';
+
+// This tests support for the dns module in snapshot.
+
+require('../common');
+const assert = require('assert');
+const tmpdir = require('../common/tmpdir');
+const fixtures = require('../common/fixtures');
+const { buildSnapshot, runWithSnapshot } = require('../common/snapshot');
+
+const entry = fixtures.path('snapshot', 'dns-resolve.js');
+const env = {
+  NODE_TEST_HOST: 'localhost',
+  NODE_TEST_PROMISE: 'true',
+};
+
+tmpdir.refresh();
+function checkOutput(stderr, stdout) {
+  // We allow failures as it's not always possible to resolve localhost.
+  // Functional tests are done in test/internet instead.
+  if (!stderr.startsWith('error:')) {
+    assert(stdout.includes('addresses: ['));
+    assert.strictEqual(stdout.trim().split('\n').length, 1);
+  }
+}
+{
+  const { stderr, stdout } = buildSnapshot(entry, env);
+  checkOutput(stderr, stdout);
+}
+
+{
+  const { stderr, stdout } = runWithSnapshot(entry, env);
+  checkOutput(stderr, stdout);
+}
diff --git a/test/parallel/test-snapshot-dns-resolve-localhost.js b/test/parallel/test-snapshot-dns-resolve-localhost.js
new file mode 100644
index 0000000000..af4576bcc3
--- /dev/null
+++ b/test/parallel/test-snapshot-dns-resolve-localhost.js
@@ -0,0 +1,34 @@
+'use strict';
+
+// This tests support for the dns module in snapshot.
+
+require('../common');
+const assert = require('assert');
+const tmpdir = require('../common/tmpdir');
+const fixtures = require('../common/fixtures');
+const { buildSnapshot, runWithSnapshot } = require('../common/snapshot');
+
+const entry = fixtures.path('snapshot', 'dns-resolve.js');
+const env = {
+  NODE_TEST_HOST: 'localhost',
+  NODE_TEST_PROMISE: 'false',
+};
+
+tmpdir.refresh();
+function checkOutput(stderr, stdout) {
+  // We allow failures as it's not always possible to resolve localhost.
+  // Functional tests are done in test/internet instead.
+  if (!stderr.startsWith('error:')) {
+    assert(stdout.includes('addresses: ['));
+    assert.strictEqual(stdout.trim().split('\n').length, 1);
+  }
+}
+{
+  const { stderr, stdout } = buildSnapshot(entry, env);
+  checkOutput(stderr, stdout);
+}
+
+{
+  const { stderr, stdout } = runWithSnapshot(entry, env);
+  checkOutput(stderr, stdout);
+}