jest

Based on Jest Roblox v3.x, generated 2026-02-07.

Jest Roblox is a Luau port of Jest for the Roblox platform. It closely follows the upstream Jest API but has critical deviations due to Luau language constraints.

Critical deviations from JS Jest:

• .never instead of .not (reserved keyword)
• jest.fn() returns two values: mock object + forwarding function
• 0, "", {} are truthy in Luau (only false and nil are falsy)
• All globals (describe, expect, jest, etc.) must be explicitly imported
• .each uses table syntax, not tagged template literals
• Custom matchers take self as first parameter

Read core-deviations first when working with this codebase.

Core References