feat(wrangler): add binding overrides to test harness

[edmundhung]

Fixes n/a.

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• Tests
  • Tests included/updated
  • Automated tests not possible - manual testing has been completed as follows:
  • Additional testing not necessary because:
• Public documentation
  • Cloudflare docs PR(s):
  • Documentation not necessary because: I will update the docs later

A picture of a cute animal (not mandatory, but encouraged)

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[changeset-bot]

🦋 Changeset detected

Latest commit: 4bc0083

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 3 packages

Name	Type
wrangler	Minor
@cloudflare/vite-plugin	Patch
@cloudflare/vitest-pool-workers	Patch

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Click here if you're a maintainer who wants to add another changeset to this PR

[workers-devprod]

Codeowners approval required for this PR:

• @cloudflare/wrangler

Show detailed file reviewers

• .changeset/tiny-oranges-sip.md: [@cloudflare/wrangler]
• fixtures/create-test-harness-example/README.md: [@cloudflare/wrangler]
• fixtures/create-test-harness-example/package.json: [@cloudflare/wrangler]
• fixtures/create-test-harness-example/tests/tsconfig.json: [@cloudflare/wrangler]
• fixtures/create-test-harness-example/tests/vitest.test.ts: [@cloudflare/wrangler]
• fixtures/create-test-harness-example/tsconfig.json: [@cloudflare/wrangler]
• fixtures/create-test-harness-example/vite.config.ts: [@cloudflare/wrangler]
• fixtures/create-test-harness-example/workers/api/worker-configuration.d.ts: [@cloudflare/wrangler]
• fixtures/create-test-harness-example/workers/mock-browser/index.ts: [@cloudflare/wrangler]
• fixtures/create-test-harness-example/workers/mock-browser/wrangler.jsonc: [@cloudflare/wrangler]
• fixtures/create-test-harness-example/workers/web/index.ts: [@cloudflare/wrangler]
• fixtures/create-test-harness-example/workers/web/worker-configuration.d.ts: [@cloudflare/wrangler]
• fixtures/create-test-harness-example/workers/web/wrangler.jsonc: [@cloudflare/wrangler]
• packages/wrangler/e2e/createTestHarness.test.ts: [@cloudflare/wrangler]
• packages/wrangler/src/api/test-harness.ts: [@cloudflare/wrangler]

[ask-bonk]

Both 2026-05-29 (10 chars) and 2026-05-29.png (sliced to 10) resolve to the same date. Consistent.

The PR is well-implemented. The core logic correctly merges binding overrides via inputBindings precedence in getBindings, the overrides only apply to configPath workers (sensible), and tests cover the override, reset, and missing-target cases. The fixtures and types are consistent.

I reviewed PR #14446 thoroughly: the binding override mechanism (bindingOverrides → service bindings → inputBindings taking precedence in getBindings), the new getExport() API, the merge ordering against vars/secrets/config bindings, the reset flow, the fixture changes, and the date-slice change in the web worker. I found no logic bugs, security issues, backward-compatibility violations, or incorrect API behavior. The changes are well-tested (override, reset reload, missing-target error) and internally consistent.

LGTM

github run

[github-actions]

✅ All changesets look good

[pkg-pr-new]

@cloudflare/autoconfig

npm i https://pkg.pr.new/@cloudflare/autoconfig@14446

create-cloudflare

npm i https://pkg.pr.new/create-cloudflare@14446

@cloudflare/deploy-helpers

npm i https://pkg.pr.new/@cloudflare/deploy-helpers@14446

@cloudflare/kv-asset-handler

npm i https://pkg.pr.new/@cloudflare/kv-asset-handler@14446

miniflare

npm i https://pkg.pr.new/miniflare@14446

@cloudflare/pages-shared

npm i https://pkg.pr.new/@cloudflare/pages-shared@14446

@cloudflare/unenv-preset

npm i https://pkg.pr.new/@cloudflare/unenv-preset@14446

@cloudflare/vite-plugin

npm i https://pkg.pr.new/@cloudflare/vite-plugin@14446

@cloudflare/vitest-pool-workers

npm i https://pkg.pr.new/@cloudflare/vitest-pool-workers@14446

@cloudflare/workers-auth

npm i https://pkg.pr.new/@cloudflare/workers-auth@14446

@cloudflare/workers-editor-shared

npm i https://pkg.pr.new/@cloudflare/workers-editor-shared@14446

@cloudflare/workers-utils

npm i https://pkg.pr.new/@cloudflare/workers-utils@14446

wrangler

npm i https://pkg.pr.new/wrangler@14446

commit: 4bc0083

[devin-ai-integration]

Devin Review found 1 potential issue.

[devin-ai-integration]

🚩 Binding override priority depends on getBindings() merge behavior

The binding overrides are set in input.bindings at packages/wrangler/src/api/test-harness.ts:366-368. In ConfigController.ts:281-284, the final bindings are constructed as { ...input.bindings, ...bindings } where bindings comes from resolveBindings() / getBindings(). At first glance this spread order would let config-resolved bindings overwrite the overrides. However, getBindings() receives input.bindings as a parameter and is expected to merge them with the right priority. The e2e tests at packages/wrangler/e2e/createTestHarness.test.ts:444-526 confirm that overrides work correctly (AI binding is replaced, call counter resets on server.reset()). Still, the correctness depends on an implicit contract in getBindings() that isn't documented — if getBindings() ever changes its merge strategy, binding overrides could silently stop working.

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