fix: mock image path as next/image expects it

[balazsorban44]

The default mock value caused next/image to throw an error.

Fixes #33976

Bug

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• Integration tests added
• Errors have helpful link attached, see contributing.md

Feature

• Implements an existing feature request or RFC. Make sure the feature request has been accepted for implementation before opening a PR.
• Related issues linked using fixes #number
• Integration tests added
• Documentation added
• Telemetry added. In case of a feature if it's used or not.
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Documentation / Examples

• Make sure the linting passes by running yarn lint

[ijjk]

Failing test suites

Commit: bb3ae26

yarn testheadless test/production/next/jest/index.test.ts

• next/jest > should work

Expand output

● next/jest › should work

thrown: "Exceeded timeout of 90000 ms for a hook.
Use jest.setTimeout(newTimeout) to increase the timeout value, if this is a long-running test."

   6 |   let next: NextInstance
   7 |
>  8 |   beforeAll(async () => {
     |   ^
   9 |     next = await createNext({
  10 |       files: {
  11 |         'public/vercel.svg':

  at production/next/jest/index.test.ts:8:3
  at Object.<anonymous> (production/next/jest/index.test.ts:5:1)

● Test suite failed to run

TypeError: Cannot read property 'destroy' of undefined

  124 |     })
  125 |   })
> 126 |   afterAll(() => next.destroy())
      |                       ^
  127 |
  128 |   it('should work', async () => {
  129 |     const html = await renderViaHTTP(next.url, '/')

  at production/next/jest/index.test.ts:126:23

Read more about building and testing Next.js in contributing.md.

[ijjk]

Stats from current PR

Default Build (Increase detected ⚠️)

General Overall increase ⚠️

	vercel/next.js canary	vercel/next.js fix/jest-img-mock	Change
buildDuration	18.3s	18.1s	-200ms
buildDurationCached	7.2s	7.1s	-35ms
nodeModulesSize	359 MB	359 MB	⚠️ +234 B

Page Load Tests Overall increase ✓

	vercel/next.js canary	vercel/next.js fix/jest-img-mock	Change
/ failed reqs	0	0	✓
/ total time (seconds)	3.588	3.619	⚠️ +0.03
/ avg req/sec	696.72	690.81	⚠️ -5.91
/error-in-render failed reqs	0	0	✓
/error-in-render total time (seconds)	1.652	1.619	-0.03
/error-in-render avg req/sec	1513.14	1544.58	+31.44

Client Bundles (main, webpack, commons)

	vercel/next.js canary	vercel/next.js fix/jest-img-mock	Change
450.HASH.js gzip	179 B	179 B	✓
framework-HASH.js gzip	42 kB	42 kB	✓
main-HASH.js gzip	27.9 kB	27.9 kB	✓
webpack-HASH.js gzip	1.44 kB	1.44 kB	✓
Overall change	71.5 kB	71.5 kB	✓

Legacy Client Bundles (polyfills)

	vercel/next.js canary	vercel/next.js fix/jest-img-mock	Change
polyfills-HASH.js gzip	31 kB	31 kB	✓
Overall change	31 kB	31 kB	✓

Client Pages

	vercel/next.js canary	vercel/next.js fix/jest-img-mock	Change
_app-HASH.js gzip	1.36 kB	1.36 kB	✓
_error-HASH.js gzip	194 B	194 B	✓
amp-HASH.js gzip	312 B	312 B	✓
css-HASH.js gzip	326 B	326 B	✓
dynamic-HASH.js gzip	2.57 kB	2.57 kB	✓
head-HASH.js gzip	350 B	350 B	✓
hooks-HASH.js gzip	919 B	919 B	✓
image-HASH.js gzip	5.05 kB	5.05 kB	✓
index-HASH.js gzip	263 B	263 B	✓
link-HASH.js gzip	2.26 kB	2.26 kB	✓
routerDirect..HASH.js gzip	321 B	321 B	✓
script-HASH.js gzip	383 B	383 B	✓
withRouter-HASH.js gzip	318 B	318 B	✓
85e02e95b279..7e3.css gzip	107 B	107 B	✓
Overall change	14.7 kB	14.7 kB	✓

Client Build Manifests

	vercel/next.js canary	vercel/next.js fix/jest-img-mock	Change
_buildManifest.js gzip	460 B	460 B	✓
Overall change	460 B	460 B	✓

Rendered Page Sizes

	vercel/next.js canary	vercel/next.js fix/jest-img-mock	Change
index.html gzip	532 B	532 B	✓
link.html gzip	545 B	545 B	✓
withRouter.html gzip	526 B	526 B	✓
Overall change	1.6 kB	1.6 kB	✓

---

Default Build with SWC (Decrease detected ✓)

General Overall increase ⚠️

	vercel/next.js canary	vercel/next.js fix/jest-img-mock	Change
buildDuration	21.7s	24.3s	⚠️ +2.5s
buildDurationCached	7.2s	7.5s	⚠️ +378ms
nodeModulesSize	359 MB	359 MB	⚠️ +234 B

Page Load Tests Overall decrease ⚠️

	vercel/next.js canary	vercel/next.js fix/jest-img-mock	Change
/ failed reqs	0	0	✓
/ total time (seconds)	3.578	3.895	⚠️ +0.32
/ avg req/sec	698.77	641.8	⚠️ -56.97
/error-in-render failed reqs	0	0	✓
/error-in-render total time (seconds)	1.575	1.878	⚠️ +0.3
/error-in-render avg req/sec	1587.22	1330.86	⚠️ -256.36

Client Bundles (main, webpack, commons)

	vercel/next.js canary	vercel/next.js fix/jest-img-mock	Change
450.HASH.js gzip	179 B	179 B	✓
framework-HASH.js gzip	42.1 kB	42.1 kB	✓
main-HASH.js gzip	27.9 kB	27.9 kB	✓
webpack-HASH.js gzip	1.44 kB	1.44 kB	✓
Overall change	71.7 kB	71.7 kB	✓

Legacy Client Bundles (polyfills)

	vercel/next.js canary	vercel/next.js fix/jest-img-mock	Change
polyfills-HASH.js gzip	31 kB	31 kB	✓
Overall change	31 kB	31 kB	✓

Client Pages

	vercel/next.js canary	vercel/next.js fix/jest-img-mock	Change
_app-HASH.js gzip	1.35 kB	1.35 kB	✓
_error-HASH.js gzip	180 B	180 B	✓
amp-HASH.js gzip	305 B	305 B	✓
css-HASH.js gzip	321 B	321 B	✓
dynamic-HASH.js gzip	2.56 kB	2.56 kB	✓
head-HASH.js gzip	342 B	342 B	✓
hooks-HASH.js gzip	911 B	911 B	✓
image-HASH.js gzip	5.08 kB	5.08 kB	✓
index-HASH.js gzip	256 B	256 B	✓
link-HASH.js gzip	2.28 kB	2.28 kB	✓
routerDirect..HASH.js gzip	314 B	314 B	✓
script-HASH.js gzip	375 B	375 B	✓
withRouter-HASH.js gzip	309 B	309 B	✓
85e02e95b279..7e3.css gzip	107 B	107 B	✓
Overall change	14.7 kB	14.7 kB	✓

Client Build Manifests

	vercel/next.js canary	vercel/next.js fix/jest-img-mock	Change
_buildManifest.js gzip	459 B	459 B	✓
Overall change	459 B	459 B	✓

Rendered Page Sizes

	vercel/next.js canary	vercel/next.js fix/jest-img-mock	Change
index.html gzip	533 B	533 B	✓
link.html gzip	547 B	547 B	✓
withRouter.html gzip	527 B	527 B	✓
Overall change	1.61 kB	1.61 kB	✓

Commit: 3c15159

[kevva]

This breaks support for SVG assets which aren't used with the Image component. Also, there's no way of overriding the default moduleNameMapper since Jest uses the first pattern that matches but you include the rules from the user after the default ones instead of before.

[balazsorban44]

Could you please open a bug report with an attached reproduction? 🙏