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Jest

Official module: dagger/jest

Install with dagger mod install github.com/dagger/jest.

What It Is​

The Jest module runs Jest tests for JavaScript and TypeScript projects.

Use it when Jest is already the test runner for the repo and you want tests to become a Dagger check.

Use It For​

  • Run Jest in CI and Dagger Cloud.
  • Check one app or package in a larger workspace.
  • List discovered tests when you need to debug test selection.

Main Workflows​

  • test: run the Jest suite.
  • list: show which tests Jest sees.

How to Use It​

Install the module, then run its check:

dagger mod install github.com/dagger/jest

dagger check          # run every check in the workspace
dagger check jest:test # run the Jest suite

test installs dependencies and runs the Jest suite over the workspace (excluding node_modules, dist, and build). It automatically registers an OpenTelemetry hook, so individual tests appear as spans in the Dagger TUI and Dagger Cloud without changing the project's Jest config.

Settings​

List the current settings and their values with dagger settings jest, then set one with dagger settings jest <key> <value>. Settings are stored in .dagger/config.toml under [modules.jest.settings].

  • packageManager (default npm): the package manager used to install dependencies before testing. Set it to yarn or pnpm to match the project.
  • baseImageAddress (default node:25-alpine): the Node base image tests run in. Pin it to the project's Node version, for example node:22-alpine.
[modules.jest.settings]
packageManager = "pnpm"
baseImageAddress = "node:22-alpine"

Test options​

The jest:test check runs with default options. Call the test function directly with dagger function call to override them:

  • files: limit the run to specific test files.
  • build: run the project's build script before testing.
  • useEnv: use the project's own Jest environment instead of the module's automatic OpenTelemetry environment.
  • flags: extra flags passed through to jest.

Use list to print the tests Jest discovers when test selection is unclear.

Workspace Fit​

Use this module when Jest is the test runner. Use Vitest instead for projects built around Vitest or Vite-first test workflows.

Source​

Source repo: github.com/dagger/jest