Vitest

The Vitest module runs Vitest tests for JavaScript and TypeScript projects as a Dagger check, locally, in CI, and in Dagger Cloud. Each Vitest or Vite config roots a project, and each project's test files are a collection, so a check can run one project, one test file, or everything.

Add it to your workspace

dagger module install dagger.io/js/vitest

Run the tests

dagger check --vitest                                            # run every Vitest project
dagger check --vitest-project=apps/web                           # run one project
dagger check --vitest-project=apps/web --vitest-test-file=src/add.test.js   # run one test file

The check is vitest/projects/tests/test. It installs dependencies and runs the project's own Vitest once per project, over the selected test files. With every file in the project selected, it runs vitest with the project's config. With some selected, it runs only those files.

The module registers an OpenTelemetry hook, so individual tests appear as spans in the Dagger TUI and Dagger Cloud without changing the project's Vitest config. Tests can call Dagger themselves.

Collections

Flag	Collection	Key
--vitest-project	projects	Directory holding the config, relative to the workspace root. The root is .
--vitest-test-file	tests, on a project	Test file path, relative to the project

List the keys with dagger list vitest-projects -a and dagger list vitest-test-files -a. Select collection items describes how to select items.

A project is a directory holding vitest.config.* or vite.config.*, with a ts, mts, cts, js, mjs, or cjs extension. Projects are found at or below the directory dagger runs from, plus the nearest project that encloses it. A nested project is a project of its own.

Test files are the files that match Vitest's default include pattern, such as *.test.ts and *.spec.js. The config's own include and exclude are not read. node_modules, .git, and nested projects are left out. A project with no test files has nothing to run.

Dependencies install at the nearest workspace root (a pnpm-workspace.yaml or a package.json with workspaces), else the nearest lockfile, else the nearest package.json. The source is mounted without node_modules and without files ignored by .gitignore.

To print the tests Vitest discovers in a project, call its list function:

dagger api call vitest project --path=apps/web list

Configure it

List the current settings and their values with dagger module settings vitest, then set one with dagger module settings vitest <key> <value>. They live in dagger.toml under [modules.vitest.settings] and apply to every project:

• packageManager (default empty) is the package manager that installs dependencies: npm, yarn, pnpm, or bun. Empty detects it from the packageManager field of package.json, then from the lockfile, then uses npm. The module enables Corepack for pnpm and Yarn.
• baseImageAddress (default node:25-alpine) is the Node base image tests run in. Pin it to the project's Node version, for example node:22-alpine.
• includeExtraFiles (default empty) are workspace-root include patterns mounted alongside the project at their workspace-relative paths, for fixtures or schemas a project imports from elsewhere in a monorepo.
• build (default false) runs the package manager's build script before the tests.
• flags (default empty) are extra flags passed to every vitest run.
• installFlags (default empty) are extra flags for the install command, such as ["--ignore-scripts"].
• environment (default empty) sets environment variables for the install and the tests, as KEY=VALUE.

[modules.vitest.settings]
baseImageAddress = "node:22-alpine"
includeExtraFiles = ["schema/*.json"]
build = true

Working with other modules

Use this module when Vitest is the test runner. Use Jest instead for projects that already depend on Jest conventions and config.

source code