mjackson/expect

Expected {} to equal {}

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#225 opened on Aug 21, 2017

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enhancementhelp wanted

Description

> expect(Object.create(null)).toEqual({})
Error: Expected {} to equal {}

They are different, because of prototype, but the output is weird.

Contributor guide

Tech stack
javascript
Domain
testing
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
basic JavaScriptunderstanding of Object.create
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
70
Research direction
Investigate the `toEqual` implementation in `expect/src/assertions.js`. The issue is that `Object.create(null)` has a null prototype, which causes a misleading error message. Check how deep equality is performed and ensure that objects with null prototype are handled correctly, perhaps by considering the prototype chain in the comparison logic.