An assertion library for cucumber.js providing cucumber compatible failures instead of exceptions

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An assertion library for cucumber.js. It allows assertions in cucumber.js without extra-long stacktraces when an assertion fails.


npm install cucumber-assert


As of Version 2.0, cucumber-assert uses Promises. If you need the old version without Promises, install Version 1.0.4:
npm install cucumber-assert@1.0.4

Example usage

var assert = require('cucumber-assert');

module.exports = function() {

	this.Given(/^the field E-Mail is filled with "([^"]*)"/, function (email, callback) {
		var fieldValue = this.getFieldValue('#password');
		assert.equal(fieldValue, email, 'Expected E-Mail to be ' + email).then(callback, callback);


Multiple operations

If you need multiple assertions in one step, you can simply wait to resolve all the Promises. Since Promise.all() will resolve with an array of the results, Promise.all(...).then(callback) would result in a broken test, since calling the callback with a parameter tells cucumber, that something went wrong. You can either use Promise.all(...).then(() => callback()) or the provided .all() Method:
var assert = require('cucumber-assert');

module.exports = function() {

	this.Given(/^the form is filled out"/, function (callback) {
		var password = this.getFieldValue('#password');
		var name = this.getFieldValue('#name');
		var tosCheck = this.getFieldValue('#tos');
        var promises = [];
		promises.push(assert.notEqual(password, '', 'Expected E-Mail to not be empty'));
		promises.push(assert.notEqual(tosCheck, '', 'Expected Name not to be empty'));
		promises.push(assert.equal(tosCheck, 'checked', 'Expected TOS to be checked'));
        assert.all(promises).then(callback, callback);

instead of
Promise.all(promises).then(() => callback(), () => callback());

Available assertions

Generally cucumber-assert wraps the assertions available by default in node. For reference see
The parameter "callback" is the callback provided by cucumber.js in step definitions and has to be passed always alongside the actual values and expectations.

equal(actual, expected, callback, message)

assert.equal(password, '', 'Expected E-Mail to be empty').then(callback);

notEqual(actual, expected, message)

assert.notEqual(password, '', 'Expected E-Mail not to be empty').then(callback);

deepEqual(actual, expected, message)

assert.deepEqual(nestedObject, expectedNestedObject).then(callback);

notDeepEqual(actual, expected, message)

assert.notDeepEqual(nestedObject, notExpectedNestedObject).then(callback);

strictEqual(actual, expected, message)

assert.strictEqual(1, 1).then(callback);

notStrictEqual(actual, expected, message)

assert.notStrictEqual(1, "1").then(callback);

throws(block, error, message)


doesNotThrow(block, message)


ifError(value, message)



See here