Jarred-Sumner · Oct 20, 2026
diff --git a/.prettierignore b/.prettierignore
@@ -1,5 +1,7 @@
 vendor
 test/snapshots
+# written by Jest and Vitest, and compared byte for byte
+test/js/bun/test/snapshot-tests/formats
 test/bundler/transpiler/react-compiler-fixtures
 src/**/*.generated.rs
 test/js/deno

diff --git a/Cargo.lock b/Cargo.lock
diff --git a/docs/bundler/css.mdx b/docs/bundler/css.mdx
@@ -932,6 +932,8 @@ This outputs:
 
 The class names are unique to each file, so they don't collide.
 
+Importing a CSS module at runtime (`bun run`, `bun test`) gives you the same object. Server-rendered markup and component tests see the same class names the bundler emits, as long as both run from the same working directory.
+
 ### Composition
 
 CSS modules can compose class selectors together to reuse style rules across multiple classes.

diff --git a/docs/docs.json b/docs/docs.json
@@ -164,6 +164,7 @@
               "/runtime/xml",
               "/runtime/jsonl",
               "/runtime/html-rewriter",
+              "/runtime/dom",
               "/runtime/image",
               "/runtime/hashing",
               "/runtime/glob",

diff --git a/docs/guides/test/migrate-from-jest.mdx b/docs/guides/test/migrate-from-jest.mdx
@@ -64,13 +64,15 @@ Bun implements most of Jest's matchers, but compatibility isn't 100%. See the co
 
 ---
 
-If you use `testEnvironment: "jsdom"` to run your tests in a browser-like environment, follow the [DOM testing with Bun and happy-dom](/guides/test/happy-dom) guide to inject browser APIs into the global scope. That guide uses [`happy-dom`](https://github.com/capricorn86/happy-dom), a leaner and faster alternative to [`jsdom`](https://github.com/jsdom/jsdom).
+Replace `testEnvironment: "jsdom"` in your Jest config with `environment` in `bunfig.toml`, and install `jsdom` itself (`bun add -d jsdom`). [`happy-dom`](https://github.com/capricorn86/happy-dom) is a leaner and faster alternative.
 
 ```toml bunfig.toml icon="settings"
 [test]
-preload = ["./happydom.ts"]
+environment = "jsdom"
 ```
 
+`@jest-environment jsdom` and `@jest-environment node` comments in test files work as-is. If a comment uses a name Bun doesn't support, such as `jest-environment-jsdom`, Bun prints a warning and runs the file without a DOM. Change it to `jsdom` or `node`. See [DOM testing](/test/dom#test-environments).
+
 ---
 
 Replace `bail` in your Jest config with the `--bail` CLI flag.

diff --git a/docs/project/benchmarking.mdx b/docs/project/benchmarking.mdx
@@ -250,6 +250,7 @@ BUN_OPTIONS="--cpu-prof-md" bun script.js
 ```sh terminal icon="terminal"
 bun --cpu-prof --cpu-prof-name my-profile.cpuprofile script.js
 bun --cpu-prof --cpu-prof-dir ./profiles script.js
+bun test --cpu-prof --cpu-prof-dir ./profiles # with --parallel, one profile for each worker
 ```
 
 | Flag                         | Description                                                 |

diff --git a/docs/runtime/bun-apis.mdx b/docs/runtime/bun-apis.mdx
@@ -31,6 +31,7 @@ Use the links in the table to jump to the associated documentation.
 | Transpiler                       | [`Bun.Transpiler`](/runtime/transpiler)                                                                                                                                                                                                                                                                                |
 | Routing                          | [`Bun.FileSystemRouter`](/runtime/file-system-router)                                                                                                                                                                                                                                                                  |
 | Streaming HTML                   | [`HTMLRewriter`](/runtime/html-rewriter)                                                                                                                                                                                                                                                                               |
+| DOM                              | [`bun:dom`](/runtime/dom)                                                                                                                                                                                                                                                                                              |
 | Headless Browser                 | [`Bun.WebView`](/runtime/webview)                                                                                                                                                                                                                                                                                      |
 | Hashing                          | [`Bun.password`](/runtime/hashing#bun-password), [`Bun.hash`](/runtime/hashing#bun-hash), [`Bun.CryptoHasher`](/runtime/hashing#bun-cryptohasher), `Bun.sha`                                                                                                                                                           |
 | CSRF Protection                  | [`Bun.CSRF.generate`](/runtime/csrf), [`Bun.CSRF.verify`](/runtime/csrf)                                                                                                                                                                                                                                               |

diff --git a/docs/runtime/bunfig.mdx b/docs/runtime/bunfig.mdx
@@ -194,6 +194,47 @@ Same as the top-level `preload` field, but only applies to `bun test`.
 preload = ["./setup.ts"]
 ```
 
+### `test.environment`
+
+The DOM that test files run with. One of `"happy-dom"`, `"jsdom"`, or `"node"` for no DOM. Default `"node"`. A `// @vitest-environment <name>` comment in a test file overrides it. See [DOM testing](/test/dom#test-environments).
+
+```toml title="bunfig.toml" icon="settings"
+[test]
+environment = "happy-dom"
+```
+
+Equivalent CLI flag: `--environment`. It overrides the `bunfig.toml` value.
+
+### `test.globals`
+
+Which module `test`, `expect` and the other globals come from. Default `"bun"`.
+
+- `"bun"`: a file that imports anything from `"vitest"` gets them from `"vitest"`. Any other file gets them from `"bun:test"`.
+- `"vitest"`: every file gets them from `"vitest"`, like `globals: true` in a Vitest project.
+
+```toml title="bunfig.toml" icon="settings"
+[test]
+globals = "vitest"
+```
+
+Equivalent CLI flag: `--globals`. It overrides the `bunfig.toml` value.
+
+### `test.reactCompiler`
+
+Compile components and hooks with Bun's built-in React Compiler. Default `false`. Experimental.
+
+- `true`: every JavaScript and TypeScript file, except test files, preload scripts and `node_modules`.
+- An array of folders or glob patterns: only the files in them.
+- A table with `include` and `exclude`: the files that `include` matches and `exclude` doesn't.
+
+```toml title="bunfig.toml" icon="settings"
+[test.reactCompiler]
+include = ["src", "packages/ui"]
+exclude = ["**/*.stories.*"]
+```
+
+Equivalent CLI flag: `--react-compiler`. See [React Compiler](/test/configuration#react-compiler).
+
 ### `test.pathIgnorePatterns`
 
 Exclude files and directories from test discovery using glob patterns. The test runner prunes matched directories during scanning, so it never traverses their contents. Use this when your project contains submodules or vendored code with `*.test.ts` files that you don't want `bun test` to pick up.
@@ -346,6 +387,17 @@ retry = 3
 
 The `--retry` CLI flag overrides this setting.
 
+### `test.clearMocks`
+
+Clear every mock function's calls and results before each test. Default `false`, or `true` for tests that use `test` from `"vitest"`.
+
+```toml title="bunfig.toml" icon="settings"
+[test]
+clearMocks = true
+```
+
+`mockReset`, `restoreMocks`, `unstubEnvs` and `unstubGlobals` work the same way. They call `vi.resetAllMocks()`, `vi.restoreAllMocks()`, `vi.unstubAllEnvs()` and `vi.unstubAllGlobals()` before each test. Default `false`.
+
 ### `test.concurrentTestGlob`
 
 Test files matching this glob pattern run all of their tests concurrently, as if you passed the `--concurrent` flag.
@@ -394,6 +446,21 @@ junit = "test-results.xml"
 
 CI systems and other tools can consume the report.
 
+#### `test.reporter.junitSuites`
+
+How the JUnit report represents `describe` blocks. Default `"nested"`.
+
+- `"nested"`: each block gets its own `<testsuite>` inside its file's `<testsuite>`.
+- `"flat"`: each file gets one `<testsuite>`, and each test's name is prefixed with the names of its blocks.
+
+```toml title="bunfig.toml" icon="settings"
+[test.reporter]
+junit = "test-results.xml"
+junitSuites = "flat"
+```
+
+Equivalent to the `--reporter-junit-suites` flag.
+
 ## Linter
 
 The `[lint]` section configures [`bun lint`](/lint). Run `bun lint --init` to add it.