●Change8

Migrating to Cloudflare Workers @cloudflare/vitest-pool-workers@0.20.0

Version @cloudflare/vitest-pool-workers@0.20.0 introduces 2 breaking changes. This guide details how to update your code.

Released: 7/31/2026

2
Breaking Changes
3
Migration Steps
8
Affected Symbols

⚠️ Check Your Code

If you use any of these symbols, you need to read this guide:

miniflare override optionsminiflare.wrappedBindingsminiflare.cacheWarnUsageminiflare.fetchMockminiflare.containerEngineminiflare.cacheminiflare.cacheAPIminiflare.unsafeStickyBlobs

Breaking Changes

●Issue #1

Removed several options from the `miniflare` override options: `wrappedBindings`, `cacheWarnUsage`, `fetchMock`, and `containerEngine`. For `fetchMock`, use `outboundService` instead. For `containerEngine`, consider using `createTestHarness()` if you need to test against actual containers.

●Issue #2

The `unsafeStickyBlobs` Miniflare option has been removed and is no longer enabled by the pool. This change has no impact on behavior as the feature it supported was dropped previously.

Migration Steps

  1. 1
    Replace `fetchMock` with `outboundService` in `miniflare` override options.
  2. 2
    If using `containerEngine` for `miniflare` overrides, consider migrating to `createTestHarness()` for testing against actual containers.
  3. 3
    Update `miniflare` configurations to use `cacheAPI` instead of the deprecated `cache` option.

Release Summary

This release removes several `miniflare` override options and deprecates the `cache` option in favor of `cacheAPI`. It also ensures backward compatibility for the `cache` option and stops enabling the removed `unsafeStickyBlobs` option.

Need More Details?

View the full release notes and all changes for Cloudflare Workers @cloudflare/vitest-pool-workers@0.20.0.

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