assert.deepEqual can generate invalid YAML output

[connor4312]

Version

v19.7.0

Platform

Linux Helios 5.10.102.1-microsoft-standard-WSL2 #1 SMP Wed Mar 2 00:30:59 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux

Subsystem

test_runner

What steps will reproduce the bug?

Have this test file:

const { test } = require("node:test");
const { deepEqual } = require("node:assert");

test("b", () => {
  deepEqual({ foo: 1 }, { foo: 2 });
});

Run it with node file.js and examine the output, or use something like tap-parser and node file.js | tap-parser

How often does it reproduce? Is there a required condition?

100%

What is the expected behavior?

It should output valid TAP

What do you see instead?

TAP version 13
# Subtest: b
not ok 1 - b
  ---
  duration_ms: 2.116422
  failureType: 'testCodeFailure'
  error: |-
    Expected values to be loosely deep-equal:
    
    {
      foo: 1
    }
    
    should loosely deep-equal
    
    {
      foo: 2
    }
  code: 'ERR_ASSERTION'
  foo: 2
  foo: 1
  operator: 'deepEqual'
  stack: |-
    TestContext.<anonymous> (/home/connor/Github/nodejs-testing/testCases/simple/workspace/test-WithADash.js:5:3)
    Test.runInAsyncScope (node:async_hooks:203:9)
    Test.run (node:internal/test_runner/test:549:25)
    Test.start (node:internal/test_runner/test:465:17)
    test (node:internal/test_runner/harness:172:18)
    Object.<anonymous> (/home/connor/Github/nodejs-testing/testCases/simple/workspace/test-WithADash.js:4:1)
    Module._compile (node:internal/modules/cjs/loader:1275:14)
    Module._extensions..js (node:internal/modules/cjs/loader:1329:10)
    Module.load (node:internal/modules/cjs/loader:1133:32)
    Module._load (node:internal/modules/cjs/loader:972:12)
  ...
1..1
# tests 1
# pass 0
# fail 1
# cancelled 0
# skipped 0
# todo 0
# duration_ms 7.64052

TAP uses YAML in its output, and here properties from the object in the deep equal check are added to the YAML. Duplicate mapping keys are invalid in YAML, and thus it breaks tap-parser, resulting in the following output:

[
  [ 'version', 13 ],
  [ 'comment', '# Subtest: b\n' ],
  [
    'assert',
    Result {
      name: 'b',
      id: 1,
      buffered: false,
      tapError: null,
      skip: false,
      todo: false,
      previous: null,
      plan: null,
      diag: null,
      time: null,
      fullname: '',
      ok: false
    }
  ],
  [
    'extra',
    '---\n' +
      '  duration_ms: 2.24284\n' +
      "  failureType: 'testCodeFailure'\n" +
      '  error: |-\n' +
      '    Expected values to be loosely deep-equal:\n' +
      '    \n' +
      '    {\n' +
      '      foo: 1\n' +
      '    }\n' +
      '    \n' +
      '    should loosely deep-equal\n' +
      '    \n' +
      '    {\n' +
      '      foo: 2\n' +
      '    }\n' +
      "  code: 'ERR_ASSERTION'\n" +
      '  foo: 2\n' +
      '  foo: 1\n' +
      "  operator: 'deepEqual'\n" +
      '  stack: |-\n' +
      '    TestContext.<anonymous> (/home/connor/Github/nodejs-testing/testCases/simple/workspace/test-WithADash.js:5:3)\n' +
      '    Test.runInAsyncScope (node:async_hooks:203:9)\n' +
      '    Test.run (node:internal/test_runner/test:549:25)\n' +
      '    Test.start (node:internal/test_runner/test:465:17)\n' +
      '    test (node:internal/test_runner/harness:172:18)\n' +
      '    Object.<anonymous> (/home/connor/Github/nodejs-testing/testCases/simple/workspace/test-WithADash.js:4:1)\n' +
      '    Module._compile (node:internal/modules/cjs/loader:1275:14)\n' +
      '    Module._extensions..js (node:internal/modules/cjs/loader:1329:10)\n' +
      '    Module.load (node:internal/modules/cjs/loader:1133:32)\n' +
      '    Module._load (node:internal/modules/cjs/loader:972:12)\n' +
      '...\n'
  ],
  [ 'plan', Plan { start: 1, end: 1, comment: '' } ],
  [ 'comment', '# tests 1\n' ],
  [ 'comment', '# pass 0\n' ],
  [ 'comment', '# fail 1\n' ],
  [ 'comment', '# cancelled 0\n' ],
  [ 'comment', '# skipped 0\n' ],
  [ 'comment', '# todo 0\n' ],
  [ 'comment', '# duration_ms 7.464937\n' ],
  [ 'comment', '# failed 1 test\n' ],
  [
    'complete',
    FinalResults {
      ok: false,
      count: 1,
      pass: 0,
      fail: 1,
      bailout: false,
      todo: 0,
      skip: 0,
      plan: FinalPlan {
        start: 1,
        end: 1,
        skipAll: false,
        skipReason: '',
        comment: ''
      },
      failures: [
        Result {
          name: 'b',
          id: 1,
          buffered: false,
          tapError: null,
          skip: false,
          todo: false,
          previous: null,
          plan: null,
          diag: null,
          time: null,
          fullname: '',
          ok: false
        }
      ],
      time: null
    }
  ],
  [ 'finish' ],
  [ 'close' ]
]

You can also verify this error by pasting the contents of the YAMLBlock in something like yamllint.

Additional information

First reported on connor4312/nodejs-testing#5