Registry / testing / cypress-websocket-server

cypress-websocket-server

library0.1.2jsnpmunverified

A Cypress plugin for mocking WebSocket servers during end-to-end tests. Version 0.1.2 is stable but low-activity. It allows defining a sequence of server and client messages in a JSON fixture file, enabling deterministic testing of WebSocket interactions. The plugin listens on localhost:1999 and enforces ordered message exchanges. Compared to other WebSocket mocking libraries, it integrates directly with Cypress commands and fixtures.

testing

npm install cypress-websocket-server

github ↗package ↗homepage ↗

INSTALL

IMPORT

SIG · CYPRESS-WEBSOCKET-

cypress-websocket-server

testingjavascriptv0.1.2

harness data pending

Install & Compatibility

Where this runs

No compatibility data collected yet for this library.

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

addCommand

✓ import { addCommand } from 'cypress-websocket-server';

✗ const addCommand = require('cypress-websocket-server').addCommand;

Package uses ESM for the addCommand export; require works but may cause issues in some bundlers

startMockWsServer

✓ const { startMockWsServer } = require('cypress-websocket-server');

✗ import { startMockWsServer } from 'cypress-websocket-server';

startMockWsServer is exported as CJS; ESM import may fail depending on environment

default import

✓ import cws from 'cypress-websocket-server';

✗ const cws = require('cypress-websocket-server').default;

Default export is not documented; package only exports named exports

Shows setup: add Cypress command and start mock server, then use cy.setWebsocketWorkflow() with a fixture file defining ordered server/client messages.

// cypress/support/index.js import { addCommand } from 'cypress-websocket-server'; addCommand(); // cypress/plugins/index.js const { startMockWsServer } = require('cypress-websocket-server'); module.exports = (on, config) => { startMockWsServer(config); }; // test file it('handles WebSocket workflow', () => { cy.visit('/'); cy.setWebsocketWorkflow('workflow.json'); // fixture file cy.get('[data-cy=connect]').click(); // server sends { message: 'connected' } and expects client { action: 'get-user' } });

Debug

Known issues

gotchaThe mock server runs on ws://localhost:1999; ensure no other service uses that port.

fix

Change port by passing options to startMockWsServer (if supported) or kill conflicting processes.

affects: >=0.0.0

gotchaWorkflow assertions are strict: client messages must match exactly the type and payload; extra or out-of-order messages cause test failure.

fix

Ensure your application sends exactly the expected messages in the correct order.

affects: >=0.0.0

Errors

Common errors & fixes

Error: WebSocket connection to 'ws://localhost:1999/' failed

Mock server not started or port in use.

fix

Verify cypress/plugins/index.js includes startMockWsServer(config). Restart Cypress.

cy.setWebsocketWorkflow is not a function

Forgot to call addCommand() in support file.

fix

In cypress/support/index.js, add: import { addCommand } from 'cypress-websocket-server'; addCommand();

Upgrade

Version history

0.1.2latest on npm

Audit

Dependencies

cypressrequiredPlugin designed to work as a Cypress plugin; cypress must be installed

Agent activity

11 hits · last 30 days

node

Amazon

Resources

githubhttps://github.com/vgeorge/cypress-websocket-server ↗

packagecypress-websocket-server ↗

homepagehttps://github.com/vgeorge/cypress-websocket-server#readme ↗