node/test/common

Node.js Core Test Common Modules

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

Table of Contents

• ArrayStream module
• Benchmark module
• Common module API
• Countdown module
• CPU Profiler module
• Debugger module
• DNS module
• Duplex pair helper
• Environment variables
• Fixtures module
• Heap dump checker module
• hijackstdio module
• HTTP2 module
• Internet module
• ongc module
• Report module
• tick module
• tmpdir module
• UDP pair helper
• WPT module

Benchmark Module

The benchmark module is used by tests to run benchmarks.

runBenchmark(name, env)

• name <string> Name of benchmark suite to be run.
• 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(...allowlist)

• allowlist <Array> Array of Globals
• return <Array>

Takes allowlist and concats that with predefined knownGlobals.

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 MiB file of all null characters.

enoughTestMem

• <boolean>

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

expectsError(validator[, exact])

• validator <Object> | <RegExp> | <Function> | <Error> The validator behaves identical to assert.throws(fn, validator).
• exact <number> default = 1
• return <Function> A callback function that expects an error.

A function suitable as callback to validate callback based errors. The error is validated using assert.throws(() => { throw error; }, validator). 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 that Node.js has been linked with a FIPS compatible OpenSSL library, and that FIPS as been enabled using --enable-fips.

To only detect if the OpenSSL library is FIPS compatible, regardless if it has been enabled or not, then process.config.variables.openssl_is_fips can be used to determine that situation.

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

isDumbTerminal

• <boolean>

isFreeBSD

• <boolean>

Platform check for Free BSD.

isIBMi

• <boolean>

Platform check for IBMi.

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.

mustNotMutateObjectDeep([target])

• target <any> default = undefined
• return <any>

If target is an Object, returns a proxy object that triggers an AssertionError on mutation attempt, including mutation of deeply nested Objects. Otherwise, it returns target directly.

Use of this function is encouraged for relevant regression tests.

import { open } from 'node:fs/promises';
import { mustNotMutateObjectDeep } from '../common/index.mjs';

const _mutableOptions = { length: 4, position: 8 };
const options = mustNotMutateObjectDeep(_mutableOptions);

// In filehandle.read or filehandle.write, attempt to mutate options will throw
// In the test code, options can still be mutated via _mutableOptions
const fh = await open('/path/to/file', 'r+');
const { buffer } = await fh.read(options);
_mutableOptions.position = 4;
await fh.write(buffer, options);

// Inline usage
const stats = await fh.stat(mustNotMutateObjectDeep({ bigint: true }));
console.log(stats.size);

Caveats: built-in objects that make use of their internal slots (for example, Maps and Sets) might not work with this function. It returns Functions directly, not preventing their mutation.

mustSucceed([fn])

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

Returns a function that accepts arguments (err, ...args). If err is not undefined or null, it triggers an AssertionError. Otherwise, it calls fn(...args).

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('node:child_process');

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

requireNoPackageJSONAbove([dir])

• dir <string> default = __dirname

Throws an AssertionError if a package.json file exists in any ancestor directory above dir. Such files may interfere with proper test functionality.

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.

skipIfDumbTerminal()

Skip the rest of the tests if the current terminal is a dumb terminal

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.

CPU Profiler module

The cpu-prof module provides utilities related to CPU profiling tests.

env

• Default: { ...process.env, NODE_DEBUG_NATIVE: 'INSPECTOR_PROFILER' }

Environment variables used in profiled processes.

getCpuProfiles(dir)

• dir {string} The directory containing the CPU profile files.
• return <string>

Returns an array of all .cpuprofile files found in dir.

getFrames(file, suffix)

• file {string} Path to a .cpuprofile file.
• suffix {string} Suffix of the URL of call frames to retrieve.
• returns { frames: <Object>, nodes: <Object> }

Returns an object containing an array of the relevant call frames and an array of all the profile nodes.

kCpuProfInterval

Sampling interval in microseconds.

verifyFrames(output, file, suffix)

• output {string}
• file {string}
• suffix {string}

Throws an AssertionError if there are no call frames with the expected suffix in the profiling data contained in file.

Debugger module

Provides common functionality for tests for node inspect.

startCLI(args[[, flags], spawnOpts])

• args <string>
• flags <string> default = []
• showOpts <Object> default = {}
• return <Object>

Returns a null-prototype object with properties that are functions and getters used to interact with the node inspect CLI. These functions are:

• flushOutput()
• waitFor()
• waitForPrompt()
• waitForInitialBreak()
• breakInfo
• ctrlC()
• output
• rawOutput
• parseSourceLines()
• writeLine()
• command()
• stepCommand()
• quit()

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.

Environment variables

The behavior of the Node.js test suite can be altered using the following environment variables.

NODE_COMMON_PORT

If set, NODE_COMMON_PORT's value overrides the common.PORT default value of 12346.

NODE_SKIP_FLAG_CHECK

If set, command line arguments passed to individual tests are not validated.

NODE_SKIP_CRYPTO

If set, crypto tests are skipped.

NODE_TEST_KNOWN_GLOBALS

A comma-separated list of variables names that are appended to the global variable allowlist. Alternatively, if NODE_TEST_KNOWN_GLOBALS is set to '0', global leak detection is disabled.

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.

Report Module

The report module provides helper functions for testing diagnostic reporting functionality.

findReports(pid, dir)

• pid <number> Process ID to retrieve diagnostic report files for.
• dir <string> Directory to search for diagnostic report files.
• return <Array>

Returns an array of diagnostic report file names found in dir. The files should have been generated by a process whose PID matches pid.

validate(filepath)

• filepath <string> Diagnostic report filepath to validate.

Validates the schema of a diagnostic report file whose path is specified in filepath. If the report fails validation, an exception is thrown.

validateContent(report)

• report <Object> | <string> JSON contents of a diagnostic report file, the parsed Object thereof, or the result of process.report.getReport().

Validates the schema of a diagnostic report whose content is specified in report. If the report fails validation, an exception is thrown.

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.

The first time refresh() runs, it adds a listener to process 'exit' that cleans the temporary directory. Thus, every file under tmpdir.path needs to be closed before the test completes. A good way to do this is to add a listener to process 'beforeExit'. If a file needs to be left open until Node.js completes, use a child process and call refresh() only in the parent.

It is usually only necessary to call refresh() once in a test file. Avoid calling it more than once in an asynchronous context as one call might refresh the temporary directory of a different context, causing the test to fail somewhat mysteriously.

UDP pair helper

The common/udppair module exports a function makeUDPPair and a class FakeUDPWrap.

FakeUDPWrap emits 'send' events when data is to be sent on it, and provides an emitReceived() API for actin as if data has been received on it.

makeUDPPair returns an object { clientSide, serverSide } where each side is an FakeUDPWrap connected to the other side.

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

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 worker thread.

See the WPT tests README for details.