tape

What is tape?

Tape is a minimalist JavaScript testing framework for Node.js. It provides a simple and straightforward way to write tests for your code, focusing on simplicity and ease of use.

What are tape's main functionalities?

Basic Test

This feature allows you to write basic tests. The example demonstrates a simple test that checks if the sum of 1 and 1 equals 2.

const test = require('tape');

test('Basic test', function (t) {
  t.plan(1);
  t.equal(1 + 1, 2, '1 + 1 should equal 2');
});

Asynchronous Test

This feature allows you to write asynchronous tests. The example demonstrates a test that performs an assertion after a 1-second delay.

const test = require('tape');

test('Asynchronous test', function (t) {
  t.plan(1);
  setTimeout(function () {
    t.equal(1 + 1, 2, '1 + 1 should equal 2');
  }, 1000);
});

Nested Tests

This feature allows you to write nested tests. The example demonstrates a parent test containing a child test.

const test = require('tape');

test('Parent test', function (t) {
  t.test('Child test', function (st) {
    st.plan(1);
    st.equal(1 + 1, 2, '1 + 1 should equal 2');
  });
  t.end();
});

Other packages similar to tape

mocha

Mocha is a feature-rich JavaScript test framework running on Node.js and in the browser, making asynchronous testing simple and fun. It provides a variety of interfaces (e.g., BDD, TDD) and supports a wide range of reporters. Compared to Tape, Mocha is more feature-rich and flexible but also more complex.

jest

Jest is a delightful JavaScript testing framework with a focus on simplicity. It works out of the box for most JavaScript projects and includes features like snapshot testing and a built-in test runner. Compared to Tape, Jest is more opinionated and comes with more built-in features, making it easier to set up but less minimalistic.

ava

AVA is a test runner for Node.js with a concise API, detailed error output, and process isolation. It runs tests concurrently, which can lead to faster test execution. Compared to Tape, AVA is more modern and provides better support for ES6/ES7 features, but it may be less familiar to those used to traditional test runners.

README

tape

tap-producing test harness for node and browsers

example

var test = require('tape');

test('timing test', function (t) {
    t.plan(2);
    
    t.equal(typeof Date.now, 'function');
    var start = Date.now();
    
    setTimeout(function () {
        t.equal(Date.now() - start, 100);
    }, 100);
});

$ node example/timing.js
TAP version 13
# timing test
ok 1 should be equal
not ok 2 should be equal
  ---
    operator: equal
    expected: 100
    actual:   107
  ...

1..2
# tests 2
# pass  1
# fail  1

methods

The assertion methods in tape are heavily influenced or copied from the methods in node-tap.

var test = require('tape')

test(name, cb)

Create a new test with an optional name string. cb(t) fires with the new test object t once all preceeding tests have finished. Tests execute serially.

If you forget to t.plan() out how many assertions you are going to run and you don't call t.end() explicitly, your test will hang.

test.skip(name, cb)

Generate a new test that will be skipped over.

t.plan(n)

Declare that n assertions should be run. t.end() will be called automatically after the nth assertion. If there are any more assertions after the nth, or after t.end() is called, they will generate errors.

t.end()

Declare the end of a test explicitly.

t.fail(msg)

Generate a failing assertion with a message msg.

t.pass(msg)

Generate a passing assertion with a message msg.

t.skip(msg)

Generate an assertion that will be skipped over.

t.ok(value, msg)

Assert that value is truthy with an optional description message msg.

Aliases: t.true(), t.assert()

t.notOk(value, msg)

Assert that value is falsy with an optional description message msg.

Aliases: t.false(), t.notok()

t.error(err, msg)

Assert that err is falsy. If err is non-falsy, use its err.message as the description message.

Aliases: t.ifError(), t.ifErr(), t.iferror()

t.equal(a, b, msg)

Assert that a === b with an optional description msg.

Aliases: t.equals(), t.isEqual(), t.is(), t.strictEqual(), t.strictEquals()

t.notEqual(a, b, msg)

Assert that a !== b with an optional description msg.

Aliases: t.notEquals(), t.notStrictEqual(), t.notStrictEquals(), t.isNotEqual(), t.isNot(), t.not(), t.doesNotEqual(), t.isInequal()

t.deepEqual(a, b, msg)

Assert that a and b have the same structure and nested values using node's deepEqual() algorithm with strict comparisons (===) on leaf nodes and an optional description msg.

Aliases: t.deepEquals(), t.isEquivalent(), t.same()

t.notDeepEqual(a, b, msg)

Assert that a and b do not have the same structure and nested values using node's deepEqual() algorithm with strict comparisons (===) on leaf nodes and an optional description msg.

Aliases: t.notEquivalent(), t.notDeeply(), t.notSame(), t.isNotDeepEqual(), t.isNotDeeply(), t.isNotEquivalent(), t.isInequivalent()

t.deepLooseEqual(a, b, msg)

Assert that a and b have the same structure and nested values using node's deepEqual() algorithm with loose comparisons (==) on leaf nodes and an optional description msg.

Aliases: t.looseEqual(), t.looseEquals()

t.notDeepLooseEqual(a, b, msg)

Assert that a and b do not have the same structure and nested values using node's deepEqual() algorithm with loose comparisons (==) on leaf nodes and an optional description msg.

Aliases: t.notLooseEqual(), t.notLooseEquals()

t.throws(fn, expected, msg)

Assert that the function call fn() throws an exception.

t.doesNotThrow(fn, expected, msg)

Assert that the function call fn() does not throw an exception.

t.test(name, cb)

Create a subtest with a new test handle st from cb(st) inside the current test t. cb(st) will only fire when t finishes. Additional tests queued up after t will not be run until all subtests finish.

var htest = test.createHarness()

Create a new test harness instance, which is a function like test(), but with a new pending stack and test state.

By default the TAP output goes to console.log(). You can pipe the output to someplace else if you htest.createStream().pipe() to a destination stream on the first tick.

test.only(name, cb)

Like test(name, cb) except if you use .only this is the only test case that will run for the entire process, all other test cases using tape will be ignored

var stream = test.createStream(opts)

Create a stream of output, bypassing the default output stream that writes messages to console.log(). By default stream will be a text stream of TAP output, but you can get an object stream instead by setting opts.objectMode to true.

tap stream reporter

You can create your own custom test reporter using this createStream() api:

var test = require('tape');
var path = require('path');

test.createStream().pipe(process.stdout);

process.argv.slice(2).forEach(function (file) {
    require(path.resolve(file));
});

You could substitute process.stdout for whatever other output stream you want, like a network connection or a file.

Pass in test files to run as arguments:

$ node tap.js test/x.js test/y.js
TAP version 13
# (anonymous)
not ok 1 should be equal
  ---
    operator: equal
    expected: "boop"
    actual:   "beep"
  ...
# (anonymous)
ok 2 should be equal
ok 3 (unnamed assert)
# wheee
ok 4 (unnamed assert)

1..4
# tests 4
# pass  3
# fail  1

object stream reporter

Here's how you can render an object stream instead of TAP:

var test = require('tape');
var path = require('path');

test.createStream({ objectMode: true }).on('data', function (row) {
    console.log(JSON.stringify(row))
});

process.argv.slice(2).forEach(function (file) {
    require(path.resolve(file));
});

The output for this runner is:

$ node object.js test/x.js test/y.js
{"type":"test","name":"(anonymous)","id":0}
{"id":0,"ok":false,"name":"should be equal","operator":"equal","actual":"beep","expected":"boop","error":{},"test":0,"type":"assert"}
{"type":"end","test":0}
{"type":"test","name":"(anonymous)","id":1}
{"id":0,"ok":true,"name":"should be equal","operator":"equal","actual":2,"expected":2,"test":1,"type":"assert"}
{"id":1,"ok":true,"name":"(unnamed assert)","operator":"ok","actual":true,"expected":true,"test":1,"type":"assert"}
{"type":"end","test":1}
{"type":"test","name":"wheee","id":2}
{"id":0,"ok":true,"name":"(unnamed assert)","operator":"ok","actual":true,"expected":true,"test":2,"type":"assert"}
{"type":"end","test":2}

install

With npm do:

npm install tape

license

MIT

Changelog

v2.12.3 - 2014-04-04

Commits

• Remove dependency on util builtin d39b0eb