strict mode: use allowUnionTypes to allow union type keyword at "#/properties/image" (strictTypes) during Jest tests

[112RG]

Prerequisites

• I have written a descriptive issue title
• I have searched existing issues to ensure the issue has not already been raised

Issue

npx jest __tests__/get.test.js -t "GET Index"
  console.warn
    strict mode: use allowUnionTypes to allow union type keyword at "#/properties/image" (strictTypes)

      at checkStrictMode (node_modules/@fastify/ajv-compiler/node_modules/ajv/lib/compile/util.ts:212:18)
      at strictTypesError (node_modules/@fastify/ajv-compiler/node_modules/ajv/lib/compile/validate/index.ts:322:18)
      at checkMultipleTypes (node_modules/@fastify/ajv-compiler/node_modules/ajv/lib/compile/validate/index.ts:294:5)
      at checkStrictTypes (node_modules/@fastify/ajv-compiler/node_modules/ajv/lib/compile/validate/index.ts:274:33)
      at schemaKeywords (node_modules/@fastify/ajv-compiler/node_modules/ajv/lib/compile/validate/index.ts:231:18)
      at typeAndKeywords (node_modules/@fastify/ajv-compiler/node_modules/ajv/lib/compile/validate/index.ts:161:3)
      at subSchemaObjCode (node_modules/@fastify/ajv-compiler/node_modules/ajv/lib/compile/validate/index.ts:147:3)

 PASS  __tests__/get.test.js
  GET Pages
    ✓ GET index (84 ms)

route
After upgrading to Fastify@V4 I have started to encounter this warning during the running of my Jest test. Now I know I should be using tap, I just haven't had to to migrate over to it yet. To my knowledge this warning only shows during test and I am guessing this is happening because of the upgrade to Ajv v8 but I am unsure reading there migration guide how to fix this.

This is the route that is being hit

  fastify.get('/', async (req, reply) => {
    return reply.view('login', { captcha: process.env.CAPTCHA_LOGIN, sitekey: process.env.CAPTCHA_SITE_KEY, token: await reply.generateCsrf() })
  })

[mcollina]

Fixing this is documented in https://ajv.js.org/strict-mode.html#strict-types. You'd need to use anyOf for one of your schemas.

Would you like to send a PR to https://github.com/fastify/fastify/blob/main/docs/Migration-Guide-V4.md? Thx

[Eomm]

Fixed in #3986