02-execution-context.md

Execution Context (t argument)

Translations: Français

Each test or hook is called with an execution context. By convention it's named t.

const test = require('ava');

test('my passing test', t => {
	t.pass();
});

Each test or hook receives a different object. It contains the assertions as well as the methods and properties listed below.

t.title

The test title.

t.context

Contains shared state from hooks.

t.passed

When used in test.afterEach() or test.afterEach.always() hooks this tells you whether the test has passed. When used in a test itself (including teardown functions) this remains true until an assertion fails, the test has ended with an error, or a teardown function caused an error. This value has no meaning in other hooks.

t.end()

End the test. Only works with test.cb(). Removed in AVA 4.

t.log(...values)

Log values contextually alongside the test result instead of immediately printing them to stdout. Behaves somewhat like console.log, but without support for placeholder tokens.

t.plan(count)

Plan how many assertions there are in the test. The test will fail if the actual assertion count doesn't match the number of planned assertions. See assertion planning.

t.teardown(fn)

Registers the fn function to be run after the test has finished. You can register multiple functions. In AVA 3 the functions are called in order, but in AVA 4 they'll run in reverse order.^†. You can use asynchronous functions: only one will run at a time.

You cannot perform assertions using the t object or register additional functions from inside fn.

You cannot use t.teardown() in hooks either.

^† You can opt in to this behavior in AVA 3 by enabling the reverseTeardowns experiment.

package.json:

{
	"ava": {
		"nonSemVerExperiments": {
			"reverseTeardowns": true
		}
	}
}

ava.config.js:

export default {
	nonSemVerExperiments: {
		reverseTeardowns: true
	}
}

t.timeout(ms)

Set a timeout for the test, in milliseconds. The test will fail if this timeout is exceeded. The timeout is reset each time an assertion is made.