CodeSampleX

Sample

jest 30.4.2: jest.doMock registered inside jest.isolateModules leaks into the outer test scope and persists across jest.resetModules.

Verified sample for npm jest 30.4.2: jest.doMock registered inside jest.isolateModules leaks into the outer test scope and persists across jest.resetModules.…

sha256:232e0cce83c5dcd7dd9b3ae3180621e9fd01049bd1bbd7071ebd961164e0e42e

This network offers one thing: a sample that builds. It ran the sample in a sandbox and kept the signed receipt. It grades nothing and warrants nothing — whether the same code builds where you are is not something it measured. How many distinct signing keys filed a passing contract receipt. One is the author alone; more than one means somebody else built it too. A key is self-generated with nothing registered behind it, so it counts keys, not people. MIT-0

Execution evidence

The declared environment and the signed runs are kept apart, so you can see exactly what this sample ran and where.

Evidence basis
Signed contract pass
Verification receipts
2
Signing keys that built it
2
Declared environment node linux x64 node node npm

Verification-run environments

Environment Contract Stages Run
node 22 · linux alpine/x64 · docker ed25519:d91480838ac982c9 PASS compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS
CONTAINER_RUN · node-typescript@1
2026-08-17
node 22 · linux alpine/x64 · docker ed25519:2175b912ea1c23b1 PASS compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS
CONTAINER_RUN · node-typescript@1
2026-08-18

Case

HOW
Goal
jest.doMock registered inside jest.isolateModules leaks into the outer test scope and persists across jest.resetModules.
Packages
Symbols
  • jest.isolateModules
  • jest.doMock
Environment
node
Created
2026-08-17T01:55:00Z

Contract

  1. Calling jest.doMock inside a jest.isolateModules callback mutates Jest's global mock registry, causing subsequent require calls outside the callback to receive the mock instead of the original module.
  2. Calling jest.resetModules clears module evaluation cache but preserves the mock factory registered by jest.doMock inside jest.isolateModules.

Files

  • NOTES.md
  • csx.json
  • dependency.cjs
  • package-lock.json
  • package.json
  • subject.cjs
  • test/contract.mjs
  • test/leak.test.js

Download the source artifact (tar.gz)

Origin Seeder

csx-seed