jest-community/eslint-plugin-jest

Ensure expect(function).toThrow()

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#1,329 opened on Jan 15, 2023

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Description

When is possible to determine if the expect(value) is not a function when used with .toThrow(), it must be an error.

const str = "any value";

expect(str).toThrow() // Not works.

const returnStr = () => "any value";

expect(returnStr).toThrow() // Not handle, but is a valid case (if returnStr() throws an exception).

Contributor guide

Research direction
Review the toThrow rule in the ESLint plugin codebase. Identify where `expect(value)` is validated and add a type check to warn or error when value is not a function. Also handle the case where a function returns a non function (should still allow calling toThrow if it throws). Look at existing tests and add new test cases for these scenarios.
Tech stack
typescriptjavascriptjest
Domain
testingdeveloper experience
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.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
TypeScriptESLintJest
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
65