Cypress-SignalR-Mock

Easy Mock SignalR hub connections in Cypress E2E tests.

Features

• Provides Cypress commands to publish and verify messages from and to the SignalR hub!
• No replacement of the Socket object on the window object!
• Multiple hubs can be mocked at the same time!
• Full TypeScript support!
• Provides mock support for all public HubConnection methods!

Compatibility

The below are not hard requirements, but the plugin is tested against these versions.

• Cypress 10.0.0 or higher
• SignalR 6.0.0 or higher
• TypeScript 4.0.0 or higher
• RxJS 6.6.0 or higher
• Node 12.0.0 or higher

Install

Install with npm:

npm install --save-dev cypress-signalr-mock

Install with yarn:

yarn add cypress-signalr-mock --dev

Install with pnpm:

pnpm add -D cypress-signalr-mock

Usage

// 01. Import the plugin to where your signalR connections are created
import {useCypressSignalRMock} from 'cypress-signalr-mock';

// 02. Call "useCypressSignalRMock" to create a mock for the SignalR hub connection
//     or use the real connection if not running in Cypress E2E mode
const progressHubConnection = useCypressSignalRMock('progress') ??
    new HubConnectionBuilder().withUrl(`http://localhost:3000/progress`).build();

// 03. Activate the plugin in your cypress/support/index.js file
import 'cypress-signalr-mock';

// 04. Use the plugin in your tests
cy.signalrPublish(
    'progress', // The name of the hub connection
    'hello-world', // The name of the message type
    {
        message: 'Hello World!', // The message payload
    },
);

How does it work

Uses Rx.js behind the scenes to create an observable that can be subscribed to. The observable is created when the createCypressSignalrMock function is called. The observable is then used to publish messages

Cypress Commands

From Server to Client

From Client to Server

Limitations

• Multiple listeners for the same message type are not supported

// This will not work

• The hubConnection.on and hubConnection.stream cannot have the same message type name.

// This will not work

Contributing

Credits

Shout-out to cypress-plugin-signalr for the inspiration and the methods used. It's unfortunately not maintained anymore, so I decided to make a spiritual successor to it.