Test Lifecycle Events

There are a few moments in the life of a test where you might want to attach some setup or teardown logic. Node-tap implements these using the following functions.

t.beforeEach(fn(done, childTest))

Before any child test (or any children of any child tests, etc.) the supplied function is called with two arguments. The first is a callback to indicate that the function is complete. The second is the test object that it's prefixing.

If the function returns a Promise, then that is used as the indication of doneness. Thus, async functions automatically end when all of their awaited Promises are complete.

t.afterEach(fn(done, childTest))

This is called after each child test (or any children of any child tests, on down the tree). Like beforeEach, it's called with a done callback as the first argument, and the child test object as the second, and can return a Promise.

t.teardown(fn())

When the test is completely finished, the teardown functions are called. They do not receive a done callback, but may return a Promise to perform asynchronous actions.

Why no t.before()?

There is no t.before() because there are other options for doing this:

• If the actions are synchronous, you can put them before your tests.
• If the actions are asynchronous, you can use a t.test().

t.on('end')

The end event fires when the test is completely finished, and all of its teardown functions have completed.

This is just a normal EventEmitter event, so it doesn't support any sort of async actions.

t.context

You can use the t.context object to track details specific to a test. For example, a beforeEach function might create a database connection, and then an afterEach function might shut it down cleanly.

const myDataBase = require('my-special-db-thingie')

t.beforeEach((done, t) => {
  t.context.connection = myDataBase.connect()
  done()
})

t.afterEach((done, t) => {
  t.context.connection.disconnect()
  done()
})

t.test('read and write', t => {
  const conn = t.context.connection
  conn.write('foo', 'bar')
  t.equal(conn.read('foo'), 'bar')
  t.end()
})