@serenity-js/assertions

Serenity/JS

Serenity/JS is a framework designed to make acceptance and regression testing of modern full-stack applications faster, more collaborative and easier to scale.

Visit serenity-js.org for the latest tutorials and API docs, and follow @SerenityJS and @JanMolak on Twitter for project updates.

Learning Serenity/JS

To learn more about Serenity/JS, check out the video below, read the tutorial, review the examples, and create your own test suite with Serenity/JS template projects.

If you have any questions, join us on Serenity/JS Community Chat.

Serenity/JS Assertions

@serenity-js/assertions is an assertions library implementing the Screenplay Pattern.

Installation

To install this module, run the following command in your computer terminal:

npm install --save-dev @serenity-js/{core,assertions}

Performing verifications using Ensure

import { actorCalled } from '@serenity-js/core';
import { Ensure, endsWith } from '@serenity-js/assertions';
import { Website } from '@serenity-js/protractor';

const actor = actorCalled('Erica');

actor.attemptsTo(
    Ensure.that(Website.title(), endsWith('Serenity/JS'))
);

Controlling execution flow using Check

import { actorCalled } from '@serenity-js/core';
import { Check } from '@serenity-js/assertions'; 
import { Click, isVisible } from '@serenity-js/protractor';

actorCalled('Erica').attemptsTo(
    Check.whether(NewsletterModal, isVisible())
        .andIfSo(Click.on(CloseModalButton)),
);

Synchronising the test with the System Under Test using Wait

import { actorCalled } from '@serenity-js/core';
import { Click, isVisible, Wait } from '@serenity-js/protractor';

actorCalled('Erica').attemptsTo(
    Wait.until(CloseModalButton, isVisible()),
    Click.on(CloseModalButton)
);

Defining custom expectations using Expectation.thatActualShould

import { actorCalled } from '@serenity-js/core';
import { Expectation, Ensure } from '@serenity-js/assertions';

function isDivisibleBy(expected: Answerable<number>): Expectation<number> {
    return Expectation.thatActualShould<number, number>('have value divisible by', expected)
        .soThat((actualValue, expectedValue) => actualValue % expectedValue === 0);
}

actorCalled('Erica').attemptsTo(
    Ensure.that(4, isDivisibleBy(2)),
);

Composing expectations using Expectation.to

import { actorCalled } from '@serenity-js/core';
import { Expectation, Ensure, and, or, isGreaterThan, isLessThan, equals  } from '@serenity-js/assertions';

function isWithin(lowerBound: number, upperBound: number) {
    return Expectation
        .to(`have value within ${ lowerBound } and ${ upperBound }`)
        .soThatActual(and(
           or(isGreaterThan(lowerBound), equals(lowerBound)),
           or(isLessThan(upperBound), equals(upperBound)),
        ));
}

actorCalled('Erica').attemptsTo(
    Ensure.that(5, isWithin(3, 6)),
);

Changelog

3.0.0-rc.23 (2022-07-19)

Bug Fixes

• node: support for Node 18 (73212bc), closes #1243