assert.equal(0/0, 0/0) fails despite both being NaN #30350

balupton · 2019-11-10T10:19:11Z

Version: v12.12.0
Platform: Darwin balupton-macbook.local 19.0.0 Darwin Kernel Version 19.0.0: Thu Oct 17 16:17:15 PDT 2019; root:xnu-6153.41.3~29/RELEASE_X86_64 x86_64
Subsystem: 64-bit

const assert = require('assert')
function log(fn) {
	try {
		fn()
	} catch (e) {
		console.error('---')
		console.error(fn.toString())
		console.error(e)
		console.error('\n')
	}
}

// nan value
log(() => assert.equal(0 / 0, 0 / 0))
log(() => assert.deepEqual(0 / 0, 0 / 0))

// nan reference
const nan = 0 / 0
log(() => assert.equal(nan, nan))
log(() => assert.deepEqual(nan, nan))

// object value
log(() => assert.deepEqual({ p: nan }, { p: nan }))

// object reference
const o = { p: nan }
log(() => assert.equal(o, o))
log(() => assert.deepEqual(o, o))

---
() => assert.equal(0 / 0, 0 / 0)
AssertionError [ERR_ASSERTION]: NaN == NaN
    at /Users/balupton/Projects/batches/obligations/promises/normalify/node-issue-30350.js:14:18
    at log (/Users/balupton/Projects/batches/obligations/promises/normalify/node-issue-30350.js:4:3)
    at Object.<anonymous> (/Users/balupton/Projects/batches/obligations/promises/normalify/node-issue-30350.js:14:1)
    at Module._compile (internal/modules/cjs/loader.js:956:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:973:10)
    at Module.load (internal/modules/cjs/loader.js:812:32)
    at Function.Module._load (internal/modules/cjs/loader.js:724:14)
    at Function.Module.runMain (internal/modules/cjs/loader.js:1025:10)
    at internal/main/run_main_module.js:17:11 {
  generatedMessage: true,
  code: 'ERR_ASSERTION',
  actual: NaN,
  expected: NaN,
  operator: '=='
}


---
() => assert.deepEqual(0 / 0, 0 / 0)
AssertionError [ERR_ASSERTION]: Expected values to be loosely deep-equal:

NaN

should loosely deep-equal

NaN
    at /Users/balupton/Projects/batches/obligations/promises/normalify/node-issue-30350.js:15:18
    at log (/Users/balupton/Projects/batches/obligations/promises/normalify/node-issue-30350.js:4:3)
    at Object.<anonymous> (/Users/balupton/Projects/batches/obligations/promises/normalify/node-issue-30350.js:15:1)
    at Module._compile (internal/modules/cjs/loader.js:956:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:973:10)
    at Module.load (internal/modules/cjs/loader.js:812:32)
    at Function.Module._load (internal/modules/cjs/loader.js:724:14)
    at Function.Module.runMain (internal/modules/cjs/loader.js:1025:10)
    at internal/main/run_main_module.js:17:11 {
  generatedMessage: true,
  code: 'ERR_ASSERTION',
  actual: NaN,
  expected: NaN,
  operator: 'deepEqual'
}


---
() => assert.equal(nan, nan)
AssertionError [ERR_ASSERTION]: NaN == NaN
    at /Users/balupton/Projects/batches/obligations/promises/normalify/node-issue-30350.js:19:18
    at log (/Users/balupton/Projects/batches/obligations/promises/normalify/node-issue-30350.js:4:3)
    at Object.<anonymous> (/Users/balupton/Projects/batches/obligations/promises/normalify/node-issue-30350.js:19:1)
    at Module._compile (internal/modules/cjs/loader.js:956:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:973:10)
    at Module.load (internal/modules/cjs/loader.js:812:32)
    at Function.Module._load (internal/modules/cjs/loader.js:724:14)
    at Function.Module.runMain (internal/modules/cjs/loader.js:1025:10)
    at internal/main/run_main_module.js:17:11 {
  generatedMessage: true,
  code: 'ERR_ASSERTION',
  actual: NaN,
  expected: NaN,
  operator: '=='
}


---
() => assert.deepEqual(nan, nan)
AssertionError [ERR_ASSERTION]: Expected values to be loosely deep-equal:

NaN

should loosely deep-equal

NaN
    at /Users/balupton/Projects/batches/obligations/promises/normalify/node-issue-30350.js:20:18
    at log (/Users/balupton/Projects/batches/obligations/promises/normalify/node-issue-30350.js:4:3)
    at Object.<anonymous> (/Users/balupton/Projects/batches/obligations/promises/normalify/node-issue-30350.js:20:1)
    at Module._compile (internal/modules/cjs/loader.js:956:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:973:10)
    at Module.load (internal/modules/cjs/loader.js:812:32)
    at Function.Module._load (internal/modules/cjs/loader.js:724:14)
    at Function.Module.runMain (internal/modules/cjs/loader.js:1025:10)
    at internal/main/run_main_module.js:17:11 {
  generatedMessage: true,
  code: 'ERR_ASSERTION',
  actual: NaN,
  expected: NaN,
  operator: 'deepEqual'
}


---
() => assert.deepEqual({ p: nan }, { p: nan })
AssertionError [ERR_ASSERTION]: Expected values to be loosely deep-equal:

{
  p: NaN
}

should loosely deep-equal

{
  p: NaN
}
    at /Users/balupton/Projects/batches/obligations/promises/normalify/node-issue-30350.js:23:18
    at log (/Users/balupton/Projects/batches/obligations/promises/normalify/node-issue-30350.js:4:3)
    at Object.<anonymous> (/Users/balupton/Projects/batches/obligations/promises/normalify/node-issue-30350.js:23:1)
    at Module._compile (internal/modules/cjs/loader.js:956:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:973:10)
    at Module.load (internal/modules/cjs/loader.js:812:32)
    at Function.Module._load (internal/modules/cjs/loader.js:724:14)
    at Function.Module.runMain (internal/modules/cjs/loader.js:1025:10)
    at internal/main/run_main_module.js:17:11 {
  generatedMessage: true,
  code: 'ERR_ASSERTION',
  actual: [Object],
  expected: [Object],
  operator: 'deepEqual'
}

The text was updated successfully, but these errors were encountered:

targos · 2019-11-10T10:25:31Z

assert.equal uses the == operator to compare values.
In JavaScript, this operator always returns false with NaN.
We recommend to use assert.strictEqual instead, which handles NaN as you would like.

balupton · 2019-11-10T10:28:36Z

ok thanks

addaleax · 2019-11-10T12:48:13Z

I do feel like assert.equal() should never fail when assert.strictEqual() succeeds, though?

This aligns the `equal` and `deepEqual()` implementations with the strict versions by accepting `NaN` as being identical in case both sides are NaN. Refs: nodejs#30350 (comment)

This aligns the `equal` and `deepEqual()` implementations with the strict versions by accepting `NaN` as being identical in case both sides are NaN. Refs: #30350 (comment) PR-URL: #30766 Reviewed-By: James M Snell <[email protected]> Reviewed-By: Denys Otrishko <[email protected]> Reviewed-By: Anna Henningsen <[email protected]> Reviewed-By: David Carlier <[email protected]> Reviewed-By: Rich Trott <[email protected]>

targos closed this as completed Nov 10, 2019

targos added the assert Issues and PRs related to the assert subsystem. label Nov 10, 2019

BridgeAR mentioned this issue Dec 2, 2019

assert: handle (deep) equal(NaN, NaN) as being identical #30766

Closed

4 tasks

rotu mentioned this issue Aug 3, 2023

assertEquals conflicts with the JavaScript's meaning of "equality" denoland/std#3513

Closed

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assert.equal(0/0, 0/0) fails despite both being NaN #30350

assert.equal(0/0, 0/0) fails despite both being NaN #30350

balupton commented Nov 10, 2019 •

edited

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targos commented Nov 10, 2019

balupton commented Nov 10, 2019

addaleax commented Nov 10, 2019

assert.equal(0/0, 0/0) fails despite both being NaN #30350

assert.equal(0/0, 0/0) fails despite both being NaN #30350

Comments

balupton commented Nov 10, 2019 • edited Loading

targos commented Nov 10, 2019

balupton commented Nov 10, 2019

addaleax commented Nov 10, 2019

balupton commented Nov 10, 2019 •

edited

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