Jasmine-SSE

A simple addon for to test a "Server Sent Event" application easily!

Installation

• Install the latest version: npm run install --save-dev jasmine-sse.
• Add the main entry point (i.e dist/jasmine-sse.js) file to your test suite.

Example

Suppose this (very) simple chat application:

let sse;
let messages = [];

function onNewMessage(e) {
  messages.push(e.data);
}

function connect() {
  if (sse) {
    return;
  }

  sse = new EventSource('/chat');
  sse.addEventListener('message', displayMessage);
}

function sendMessage(message) {
  fetch('/chat', {
    method: 'POST',
    body: JSON.stringify({message}),
    headers: {
      'Content-Type': 'application/json; charset=utf-8',
    },
  });
}

function disconnect() {
  if (sse) {
    sse.close();
    sse.removeEventListener('message', displayMessage);
    sse = null;
  }
}

Testing this application can be easy with jasmine-sse:

describe('app', () => {
  beforeEach(() => {
    jasmine.sse().install();
  });

  afterEach(() => {
    jasmine.sse().uninstall();
  });

  it('should connect sse', () => {
    connect();

    const connections = jasmine.sse().connections();
    expect(connections.count()).toBe(1);
    
    const connection = connections.mostRecent();
    expect(connection.url).toBe('...');
    expect(connection.readyState).toBe(0);
    expect(messages).toEqual([]);

    connection.emit('Hi dude');
    expect(messages).toEqual(['Hi dude']);

    // Or with an object containing event type.
    connection.emit({
      type: 'custom',
      message: 'Hi bob',
    });

    expect(messages).toEqual(['Hi dude']);

    disconnect();
    expect(sse.getEventListeners()).toEqual([]);
  });
});

API

jasmine.sse

jasmine.sse().install()

Install the fake EventSource implementation, typically called in a beforeEach method. Note that:

• The fake implementation is installed if, and only if, a native EventSource implementaton is available (i.e if browser supports EventSource), otherwise this method do nothing (and do not fail).
• This method will fail if jasmine-sse has already been installed.

jasmine.sse().uninstall()

Install the fake EventSource implementation, typically called in a beforeEach method. Note that:

• Like the jasmine.sse().install() method, if browser does not support native EventSource this method do nothing (and do not fail).
• This method will fail if jasmine-sse has not been previously installed.

jasmine.sse().connections()

Returns an object containing methods to get tracked connection:

• count(): number Get the number of tracked connections.
• all(): Array<FakeEventSource> Get an array of all tracked connections.
• first(): FakeEventSource Get the first tracked connections or undefined.
• last(): FakeEventSource Get the last tracked connections or undefined.
• at(idx: number): FakeEventSource Get the tracked connection at given index or undefined.

jasmine.sse().withMock(testFn)

Install the fake EventSource implementation, execute the test function testFn, then reset the fake implementation. This method can be used to install/uninstall fake EventSource API in a single test, for example:

it('should run test with fake implementation', () => {
  jasmine.sse().withMock(() => {
    doYourTest();
    doYourExpect();
  });
});

FakeEventSource

A tracked connection is a fake EventSource (so contains all methods of EventSource object as documented here) with additional methods:

• emit(message: string|object): void Emit a message from the server.
• failConnection(): void Fail the connection, typically used to test a connection failure from server.
• reestablishConnection(): Array<string> Reestablish connection, typically used to test connection establishment.
• getEventListeners(eventType?: string): Array<function> Get registered listeners (passing string parameter will return registered event listeners for given event type).

Licence

MIT License (MIT)

Contributing

If you find a bug or you think something is missing, feel free to contribute and submit an issue or a pull request.