Node.js Core Test Common Modules

This directory contains modules used to test the Node.js implementation.

Table of Contents

• Benchmark module
• Common module API
• Countdown module
• DNS module
• Duplex pair helper
• Fixtures module
• Heap dump checker module
• HTTP2 module
• Internet module
• tick module
• tmpdir module
• WPT module

Benchmark Module

The benchmark module is used by tests to run benchmarks.

runBenchmark(name, args, env)

• name <string> Name of benchmark suite to be run.
• args <Array> Array of environment variable key/value pairs (ex: n=1) to be applied via --set.
• env <Object> Environment variables to be applied during the run.

Common Module API

The common module is used by tests for consistency across repeated tasks.

allowGlobals(...whitelist)

• whitelist <Array> Array of Globals
• return <Array>

Takes whitelist and concats that with predefined knownGlobals.

busyLoop(time)

• time <number>

Blocks for time amount of time.

canCreateSymLink()

• return <boolean>

Checks whether the current running process can create symlinks. On Windows, this returns false if the process running doesn't have privileges to create symlinks (SeCreateSymbolicLinkPrivilege). On non-Windows platforms, this always returns true.

createZeroFilledFile(filename)

Creates a 10 MB file of all null characters.

disableCrashOnUnhandledRejection()

Removes the process.on('unhandledRejection') handler that crashes the process after a tick. The handler is useful for tests that use Promises and need to make sure no unexpected rejections occur, because currently they result in silent failures. However, it is useful in some rare cases to disable it, for example if the unhandledRejection hook is directly used by the test.

enoughTestMem

• <boolean>

Indicates if there is more than 1gb of total memory.

expectsError([fn, ]settings[, exact])

• fn <Function> a function that should throw.

• settings <Object> that must contain the code property plus any of the other following properties (some properties only apply for AssertionError):

  • code <string> expected error must have this value for its code property.
  • type <Function> expected error must be an instance of type and must be an Error subclass.
  • message <string> or <RegExp> if a string is provided for message, expected error must have it for its message property; if a regular expression is provided for message, the regular expression must match the message property of the expected error.
  • name <string> expected error must have this value for its name property.
  • info <Object> expected error must have the same info property that is deeply equal to this value.
  • generatedMessage <string> (AssertionError only) expected error must have this value for its generatedMessage property.
  • actual <any> (AssertionError only) expected error must have this value for its actual property.
  • expected <any> (AssertionError only) expected error must have this value for its expected property.
  • operator <any> (AssertionError only) expected error must have this value for its operator property.

• exact <number> default = 1

• return <Function>

  If fn is provided, it will be passed to assert.throws as first argument and undefined will be returned. Otherwise a function suitable as callback or for use as a validation function passed as the second argument to assert.throws() will be returned. If the returned function has not been called exactly exact number of times when the test is complete, then the test will fail.

expectWarning(name[, expected[, code]])

• name <string> | <Object>
• expected <string> | <Array> | <Object>
• code <string>

Tests whether name, expected, and code are part of a raised warning.

The code is required in case the name is set to 'DeprecationWarning'.

Examples:

const { expectWarning } = require('../common');

expectWarning('Warning', 'Foobar is really bad');

expectWarning('DeprecationWarning', 'Foobar is deprecated', 'DEP0XXX');

expectWarning('DeprecationWarning', [
  'Foobar is deprecated', 'DEP0XXX'
]);

expectWarning('DeprecationWarning', [
  ['Foobar is deprecated', 'DEP0XXX'],
  ['Baz is also deprecated', 'DEP0XX2']
]);

expectWarning('DeprecationWarning', {
  DEP0XXX: 'Foobar is deprecated',
  DEP0XX2: 'Baz is also deprecated'
});

expectWarning({
  DeprecationWarning: {
    DEP0XXX: 'Foobar is deprecated',
    DEP0XX1: 'Baz is also deprecated'
  },
  Warning: [
    ['Multiple array entries are fine', 'SpecialWarningCode'],
    ['No code is also fine']
  ],
  SingleEntry: ['This will also work', 'WarningCode'],
  SingleString: 'Single string entries without code will also work'
});

getArrayBufferViews(buf)

• buf <Buffer>
• return <ArrayBufferView[]>

Returns an instance of all possible ArrayBufferViews of the provided Buffer.

getBufferSources(buf)

• buf <Buffer>
• return [<BufferSource[]>]

Returns an instance of all possible BufferSources of the provided Buffer, consisting of all ArrayBufferView and an ArrayBuffer.

getCallSite(func)

• func <Function>
• return <string>

Returns the file name and line number for the provided Function.

getTTYfd()

Attempts to get a valid TTY file descriptor. Returns -1 if it fails.

The TTY file descriptor is assumed to be capable of being writable.

hasCrypto

• <boolean>

Indicates whether OpenSSL is available.

hasFipsCrypto

• <boolean>

Indicates hasCrypto and crypto with fips.

hasIntl

• <boolean>

Indicates if internationalization is supported.

hasIPv6

• <boolean>

Indicates whether IPv6 is supported on this platform.

hasMultiLocalhost

• <boolean>

Indicates if there are multiple localhosts available.

inFreeBSDJail

• <boolean>

Checks whether free BSD Jail is true or false.

isAIX

• <boolean>

Platform check for Advanced Interactive eXecutive (AIX).

isAlive(pid)

• pid <number>
• return <boolean>

Attempts to ‘kill’ pid

isFreeBSD

• <boolean>

Platform check for Free BSD.

isLinux

• <boolean>

Platform check for Linux.

isLinuxPPCBE

• <boolean>

Platform check for Linux on PowerPC.

isOSX

• <boolean>

Platform check for macOS.

isSunOS

• <boolean>

Platform check for SunOS.

isWindows

• <boolean>

Platform check for Windows.

localhostIPv4

• <string>

IP of localhost.

localIPv6Hosts

• <Array>

Array of IPV6 representations for localhost.

mustCall([fn][, exact])

• fn <Function> default = () => {}
• exact <number> default = 1
• return <Function>

Returns a function that calls fn. If the returned function has not been called exactly exact number of times when the test is complete, then the test will fail.

If fn is not provided, an empty function will be used.

mustCallAtLeast([fn][, minimum])

• fn <Function> default = () => {}
• minimum <number> default = 1
• return <Function>

Returns a function that calls fn. If the returned function has not been called at least minimum number of times when the test is complete, then the test will fail.

If fn is not provided, an empty function will be used.

mustNotCall([msg])

• msg <string> default = ‘function should not have been called’
• return <Function>

Returns a function that triggers an AssertionError if it is invoked. msg is used as the error message for the AssertionError.

nodeProcessAborted(exitCode, signal)

• exitCode <number>
• signal <string>
• return <boolean>

Returns true if the exit code exitCode and/or signal name signal represent the exit code and/or signal name of a node process that aborted, false otherwise.

opensslCli

• <boolean>

Indicates whether ‘opensslCli’ is supported.

platformTimeout(ms)

• ms <number> | <bigint>
• return <number> | <bigint>

Returns a timeout value based on detected conditions. For example, a debug build may need extra time so the returned value will be larger than on a release build.

PIPE

• <string>

Path to the test socket.

PORT

• <number>

A port number for tests to use if one is needed.

printSkipMessage(msg)

• msg <string>

Logs '1..0 # Skipped: ' + msg

pwdCommand

• <array> First two argument for the spawn/exec functions.

Platform normalized pwd command options. Usage example:

const common = require('../common');
const { spawn } = require('child_process');

spawn(...common.pwdCommand, { stdio: ['pipe'] });

rootDir

• <string>

Path to the ‘root’ directory. either / or c:\\ (windows)

runWithInvalidFD(func)

• func <Function>

Runs func with an invalid file descriptor that is an unsigned integer and can be used to trigger EBADF as the first argument. If no such file descriptor could be generated, a skip message will be printed and the func will not be run.

skip(msg)

• msg <string>

Logs '1..0 # Skipped: ' + msg and exits with exit code 0.

skipIfEslintMissing()

Skip the rest of the tests in the current file when ESLint is not available at tools/node_modules/eslint

skipIfInspectorDisabled()

Skip the rest of the tests in the current file when the Inspector was disabled at compile time.

skipIf32Bits()

Skip the rest of the tests in the current file when the Node.js executable was compiled with a pointer size smaller than 64 bits.

skipIfWorker()

Skip the rest of the tests in the current file when not running on a main thread.

ArrayStream Module

The ArrayStream module provides a simple Stream that pushes elements from a given array.

const ArrayStream = require('../common/arraystream');
const stream = new ArrayStream();
stream.run(['a', 'b', 'c']);

It can be used within tests as a simple mock stream.

Countdown Module

The Countdown module provides a simple countdown mechanism for tests that require a particular action to be taken after a given number of completed tasks (for instance, shutting down an HTTP server after a specific number of requests). The Countdown will fail the test if the remainder did not reach 0.

const Countdown = require('../common/countdown');

function doSomething() {
  console.log('.');
}

const countdown = new Countdown(2, doSomething);
countdown.dec();
countdown.dec();

new Countdown(limit, callback)

• limit {number}
• callback {function}

Creates a new Countdown instance.

Countdown.prototype.dec()

Decrements the Countdown counter.

Countdown.prototype.remaining

Specifies the remaining number of times Countdown.prototype.dec() must be called before the callback is invoked.

DNS Module

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)

• buffer <Buffer>
• offset <number>
• return <Object>

Reads the domain string from a packet and returns an object containing the number of bytes read and the domain.

parseDNSPacket(buffer)

• buffer <Buffer>
• return <Object>

Parses a DNS packet. Returns an object with the values of the various flags of the packet depending on the type of packet.

writeIPv6(ip)

• ip <string>
• return <Buffer>

Reads an IPv6 String and returns a Buffer containing the parts.

writeDomainName(domain)

• domain <string>
• return <Buffer>

Reads a Domain String and returns a Buffer containing the domain.

writeDNSPacket(parsed)

• parsed <Object>
• return <Buffer>

Takes in a parsed Object and writes its fields to a DNS packet as a Buffer object.

Duplex pair helper

The common/duplexpair module exports a single function makeDuplexPair, which returns an object { clientSide, serverSide } where each side is a Duplex stream connected to the other side.

There is no difference between client or server side beyond their names.

Fixtures Module

The common/fixtures module provides convenience methods for working with files in the test/fixtures directory.

fixtures.fixturesDir

• <string>

The absolute path to the test/fixtures/ directory.

fixtures.path(...args)

• ...args <string>

Returns the result of path.join(fixtures.fixturesDir, ...args).

fixtures.readSync(args[, enc])

• args <string> | <Array>

Returns the result of fs.readFileSync(path.join(fixtures.fixturesDir, ...args), 'enc').

fixtures.readKey(arg[, enc])

• arg <string>

Returns the result of fs.readFileSync(path.join(fixtures.fixturesDir, 'keys', arg), 'enc').

Heap dump checker module

This provides utilities for checking the validity of heap dumps. This requires the usage of --expose-internals.

heap.recordState()

Create a heap dump and an embedder graph copy for inspection. The returned object has a validateSnapshotNodes function similar to the one listed below. (heap.validateSnapshotNodes(...) is a shortcut for heap.recordState().validateSnapshotNodes(...).)

heap.validateSnapshotNodes(name, expected, options)

• name <string> Look for this string as the name of heap dump nodes.
• expected <Array> A list of objects, possibly with an children property that points to expected other adjacent nodes.
• options <Array>
  • loose <boolean> Do not expect an exact listing of occurrences of nodes with name name in expected.

Create a heap dump and an embedder graph copy and validate occurrences.

validateSnapshotNodes('TLSWRAP', [
  {
    children: [
      { name: 'enc_out' },
      { name: 'enc_in' },
      { name: 'TLSWrap' }
    ]
  }
]);

hijackstdio Module

The hijackstdio module provides utility functions for temporarily redirecting stdout and stderr output.

const { hijackStdout, restoreStdout } = require('../common/hijackstdio');

hijackStdout((data) => {
  /* Do something with data */
  restoreStdout();
});

console.log('this is sent to the hijacked listener');

hijackStderr(listener)

• listener <Function>: a listener with a single parameter called data.

Eavesdrop to process.stderr.write() calls. Once process.stderr.write() is called, listener will also be called and the data of write function will be passed to listener. What's more, process.stderr.writeTimes is a count of the number of calls.

hijackStdout(listener)

• listener <Function>: a listener with a single parameter called data.

Eavesdrop to process.stdout.write() calls. Once process.stdout.write() is called, listener will also be called and the data of write function will be passed to listener. What's more, process.stdout.writeTimes is a count of the number of calls.

restoreStderr()

Restore the original process.stderr.write(). Used to restore stderr to its original state after calling hijackstdio.hijackStdErr().

restoreStdout()

Restore the original process.stdout.write(). Used to restore stdout to its original state after calling hijackstdio.hijackStdOut().

HTTP/2 Module

The http2.js module provides a handful of utilities for creating mock HTTP/2 frames for testing of HTTP/2 endpoints

const http2 = require('../common/http2');

Class: Frame

The http2.Frame is a base class that creates a Buffer containing a serialized HTTP/2 frame header.

// length is a 24-bit unsigned integer
// type is an 8-bit unsigned integer identifying the frame type
// flags is an 8-bit unsigned integer containing the flag bits
// id is the 32-bit stream identifier, if any.
const frame = new http2.Frame(length, type, flags, id);

// Write the frame data to a socket
socket.write(frame.data);

The serialized Buffer may be retrieved using the frame.data property.

Class: DataFrame extends Frame

The http2.DataFrame is a subclass of http2.Frame that serializes a DATA frame.

// id is the 32-bit stream identifier
// payload is a Buffer containing the DATA payload
// padlen is an 8-bit integer giving the number of padding bytes to include
// final is a boolean indicating whether the End-of-stream flag should be set,
// defaults to false.
const frame = new http2.DataFrame(id, payload, padlen, final);

socket.write(frame.data);

Class: HeadersFrame

The http2.HeadersFrame is a subclass of http2.Frame that serializes a HEADERS frame.

// id is the 32-bit stream identifier
// payload is a Buffer containing the HEADERS payload (see either
// http2.kFakeRequestHeaders or http2.kFakeResponseHeaders).
// padlen is an 8-bit integer giving the number of padding bytes to include
// final is a boolean indicating whether the End-of-stream flag should be set,
// defaults to false.
const frame = new http2.HeadersFrame(id, payload, padlen, final);

socket.write(frame.data);

Class: SettingsFrame

The http2.SettingsFrame is a subclass of http2.Frame that serializes an empty SETTINGS frame.

// ack is a boolean indicating whether or not to set the ACK flag.
const frame = new http2.SettingsFrame(ack);

socket.write(frame.data);

http2.kFakeRequestHeaders

Set to a Buffer instance that contains a minimal set of serialized HTTP/2 request headers to be used as the payload of a http2.HeadersFrame.

const frame = new http2.HeadersFrame(1, http2.kFakeRequestHeaders, 0, true);

socket.write(frame.data);

http2.kFakeResponseHeaders

Set to a Buffer instance that contains a minimal set of serialized HTTP/2 response headers to be used as the payload a http2.HeadersFrame.

const frame = new http2.HeadersFrame(1, http2.kFakeResponseHeaders, 0, true);

socket.write(frame.data);

http2.kClientMagic

Set to a Buffer containing the preamble bytes an HTTP/2 client must send upon initial establishment of a connection.

socket.write(http2.kClientMagic);

Internet Module

The common/internet module provides utilities for working with internet-related tests.

internet.addresses

• <Object>
  • INET_HOST <string> A generic host that has registered common DNS records, supports both IPv4 and IPv6, and provides basic HTTP/HTTPS services
  • INET4_HOST <string> A host that provides IPv4 services
  • INET6_HOST <string> A host that provides IPv6 services
  • INET4_IP <string> An accessible IPv4 IP, defaults to the Google Public DNS IPv4 address
  • INET6_IP <string> An accessible IPv6 IP, defaults to the Google Public DNS IPv6 address
  • INVALID_HOST <string> An invalid host that cannot be resolved
  • MX_HOST <string> A host with MX records registered
  • SRV_HOST <string> A host with SRV records registered
  • PTR_HOST <string> A host with PTR records registered
  • NAPTR_HOST <string> A host with NAPTR records registered
  • SOA_HOST <string> A host with SOA records registered
  • CNAME_HOST <string> A host with CNAME records registered
  • NS_HOST <string> A host with NS records registered
  • TXT_HOST <string> A host with TXT records registered
  • DNS4_SERVER <string> An accessible IPv4 DNS server
  • DNS6_SERVER <string> An accessible IPv6 DNS server

A set of addresses for internet-related tests. All properties are configurable via NODE_TEST_* environment variables. For example, to configure internet.addresses.INET_HOST, set the environment variable NODE_TEST_INET_HOST to a specified host.

ongc Module

The ongc module allows a garbage collection listener to be installed. The module exports a single onGC() function.

require('../common');
const onGC = require('../common/ongc');

onGC({}, { ongc() { console.log('collected'); } });

onGC(target, listener)

• target <Object>
• listener <Object>
  • ongc <Function>

Installs a GC listener for the collection of target.

This uses async_hooks for GC tracking. This means that it enables async_hooks tracking, which may affect the test functionality. It also means that between a global.gc() call and the listener being invoked a full setImmediate() invocation passes.

listener is an object to make it easier to use a closure; the target object should not be in scope when listener.ongc() is created.

tick Module

The tick module provides a helper function that can be used to call a callback after a given number of event loop “ticks”.

tick(x, cb)

• x <number> Number of event loop “ticks”.
• cb <Function> A callback function.

tmpdir Module

The tmpdir module supports the use of a temporary directory for testing.

path

• <string>

The realpath of the testing temporary directory.

refresh()

Deletes and recreates the testing temporary directory.

WPT Module

harness

A legacy port of Web Platform Tests harness.

See the source code for definitions. Please avoid using it in new code - the current usage of this port in tests is being migrated to the original WPT harness, see the WPT tests README.

Class: WPTRunner

A driver class for running WPT with the WPT harness in a vm.

See the WPT tests README for details.