enzymejs/enzyme

Enzyme's `React.lazy` support is reducing coverage

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#2,238 opened on Sep 13, 2019

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help wanted

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Description

Current behavior

Screen Shot 2019-08-14 at 11 49 32 AM

Expected behavior

React.lazy line is covered.

Reference: https://github.com/airbnb/enzyme/issues/1917#issuecomment-521326956

@ljharb created a new issue for you as suggested.

Your environment

API

  • shallow
  • mount
  • render

Version

library version
enzyme 3.10.0
react 16.9.x
react-dom 16.9.x
react-test-renderer 16.9.x
adapter (below)

Adapter

  • enzyme-adapter-react-16

Contributor guide

Research direction
Investigate how React.lazy is rendered in Enzyme and trace coverage reporting to understand why lazy loaded components reduce line coverage. Look at the Enzyme adapter for React 16 and how it handles React.lazy. Check if there is a missing mock or wrapper that causes the lazy component to not be executed during tests.
Tech stack
javascriptreact
Domain
testingfrontend
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
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.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Mostly clear
Prerequisites
JavaScriptReactEnzymeJest
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
40