tape-promise
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    4.0.0 • Public • Published

    tape-promise

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    Promise and ES2016 (ES7) async/await support for Tape.

    This module assumes that you're familiar with at least the concepts of Promises and if you want to use async/await, then you must be familiar with Babel.

    Install

    npm i --save-dev tape-promise
    

    Usage

    Make sure that you have tape installed:

    npm i --save-dev tape
    

    Unlike blue-tape, tape-promise is just a decorator (not an ES7 decorator). That is, it does NOT depend upon tape and requires that you pass it in.

    ES5

    var tape = require('tape')
    var _test = require('tape-promise').default // <---- notice 'default'
    var test = _test(tape) // decorate tape

    ES6 (ES2015)

    import tape from 'tape'
    import _test from 'tape-promise'
    const test = _test(tape) // decorate tape

    or, for convenience...

    import test from 'tape-promise/tape'

    but you must explicitly have tape as a dependency.

    Example (promises)

    Just return the promise.

    // example function that returns a Promise
    function delay (time) {
      return new Promise(function (resolve, reject) {
        setTimeout(function () {
          resolve()
        }, time)
      })
    }
     
    test('ensure promises works', function (t) {
      return delay(100).then(function () {
        t.true(true)
      })
    })

    Example (async/await)

    Async/await functions just transform to Promises. Don't forget to put the async keyword on your function.

    // example function that returns a Promise
    // it could also be an async function
    function delay (time) {
      return new Promise(function (resolve, reject) {
        setTimeout(function () {
          resolve()
        }, time)
      })
    }
     
    // NOTICE 'async'?
    test('ensure async works', async function (t) {
      await delay(100)
      t.true(true)
      t.end() // not really necessary
    })

    Example (normal tape tests)

    Of course you can write normal tape tests as you would.

    test('ensure that regular test functions still work', function (t) {
      t.true(true)
      t.end()
    })

    New Assertions

    t.rejects(promise, expected, msg)

    Assert that the promise will reject.

    If promise is a function, then it is called, and the returned promise is used.

    expected is the error that should be rejected with, if present, must be a RegExp or Function. The RegExp matches the string representation of the exception, as generated by err.toString(). The Function is the exception thrown (e.g. Error). If the promise rejects, but its error doesn't match expected, then the assertion fails.

    msg is an optional description of the assertion.

    This function returns a promise that resolves when the assertion is complete (after the promise is settled). The test will not wait for the assertion automatically, so it needs to be awaited.

    t.doesNotReject(promise, expected, msg)

    Assert that the promise will resolve.

    If promise is a function, then it is called, and the returned promise is used.

    expected is the error that the promise shouldn't reject with, if present, it must be a RegExp or Function. The RegExp matches the string representation of the exception, as generated by err.toString(). The Function is the exception thrown (e.g. Error). If the promise rejects, but its error doesn't match expected, then the assertion passes.

    msg is an optional description of the assertion.

    This function returns a promise that resolves when the assertion is complete (after the promise is settled). The test will not wait for the assertion automatically, so it needs to be awaited.

    example

    test('reject and doesNotReject example', async (t) => {
      await t.rejects(asyncFunction)
      await t.rejects(asyncFunction())
      await t.doesNotReject(Promise.resolve())
    })

    License

    Licensed under MIT

    Copyright (c) JP Richardson

    Install

    npm i tape-promise

    DownloadsWeekly Downloads

    4,432

    Version

    4.0.0

    License

    MIT

    Unpacked Size

    12.6 kB

    Total Files

    8

    Last publish

    Collaborators

    • jprichardson
    • ryanzim