jest_test

JavaScript and TypeScript tests run with Jest.

Start Here

Install Jest in the package with the project's JavaScript package manager, or make the jest command available on the executable search path. For example:

npm install --save-dev jest

Retrieve the runnable starter when you want a complete declaration, package manifest, and sample tests:

once query example jest_test jest-test-minimal --format json

Copy the declaration below into once.toml, adjust srcs and any setup files for the project, then establish discovery and run the file batches:

once test tests --format json
once query test-manifest tests --format json
once test tests --jobs 4 --format json

The first command runs the complete target. Later runs can use the resulting manifest for automatic batching and exact selection. See Testing and Scheduling for affected plans, case-level batching, and exact unit commands.

Description

jest_test prefers the package-local Jest entry point, then falls back to the installed jest command. It uses structured output, records stable file and full-name identifiers, and writes normalized Once results. Exact execution selects the discovered file and an anchored test name pattern.

The target kind declares Node.js and Jest as tool requirements. A workspace-relative runner is treated as an input, while an installed runner is identified as part of the toolchain.

Automatic batching uses one batch per test file by default. Set batching to case for individual cases, or target for one target batch. A complete run must establish a current manifest before smaller batches are planned. Once disables Jest's mutable local cache inside the action because installed packages are declared inputs. Once's action cache reuses successful test results when those inputs have not changed.

Attributes

Attribute	Type	Required	Default	Description
node	string	no	node	Node.js executable name, absolute path, or workspace-relative path
runner	string	no	automatic	Package-relative Jest entry point or installed command. Once prefers node_modules/jest/bin/jest.js, then searches for jest
config	list<string>	no	package and lock files	Dependency and runner configuration inputs
dependencies	list<string>	no	node_modules/**/*	Installed runner and package files required during execution
data	list<string>	no	[]	Setup, transform, snapshot, and runtime inputs
args	list<string>	no	[]	Additional Jest arguments
env	map<string, string>	no	{}	Explicit test environment variables
env_inherit	list<string>	no	[]	Host environment variables inherited by name
batching	string	no	file	Automatic granularity: file, case, or target
labels	list<string>	no	[]	Labels exposed through test discovery
timeout_ms	int	no	empty	Optional timeout in milliseconds

Dependency Edges

deps names targets whose changes should select this test target.

Providers and Capabilities

The target emits once_test_info and exposes test with the default, test_results, and logs output groups.

Example

[[target]]
name = "tests"
kind = "jest_test"
srcs = ["tests/**/*.test.js"]

Include setup files, transforms, snapshots, and other runtime files in data.