feat: add base implementation for realtime communication

Signed-off-by: Philip Molares <philip.molares@udo.edu>
Signed-off-by: Erik Michelson <github@erik.michelson.eu>
Co-authored-by: Erik Michelson <github@erik.michelson.eu>
Co-authored-by: Philip Molares <philip.molares@udo.edu>
Co-authored-by: Tilman Vatteroth <git@tilmanvatteroth.de>
Signed-off-by: Tilman Vatteroth <git@tilmanvatteroth.de>

src/realtime/realtime-note/realtime-note.spec.ts

@@ -0,0 +1,79 @@
+/*
+ * SPDX-FileCopyrightText: 2022 The HedgeDoc developers (see AUTHORS file)
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+import { RealtimeNote } from './realtime-note';
+import { mockAwareness } from './test-utils/mock-awareness';
+import { mockConnection } from './test-utils/mock-connection';
+import { mockWebsocketDoc } from './test-utils/mock-websocket-doc';
+import * as websocketAwarenessModule from './websocket-awareness';
+import { WebsocketAwareness } from './websocket-awareness';
+import * as websocketDocModule from './websocket-doc';
+import { WebsocketDoc } from './websocket-doc';
+
+describe('realtime note', () => {
+  let mockedDoc: WebsocketDoc;
+  let mockedAwareness: WebsocketAwareness;
+
+  beforeEach(() => {
+    jest.resetAllMocks();
+    jest.resetModules();
+    mockedDoc = mockWebsocketDoc();
+    mockedAwareness = mockAwareness();
+    jest
+      .spyOn(websocketDocModule, 'WebsocketDoc')
+      .mockImplementation(() => mockedDoc);
+    jest
+      .spyOn(websocketAwarenessModule, 'WebsocketAwareness')
+      .mockImplementation(() => mockedAwareness);
+  });
+
+  afterAll(() => {
+    jest.resetAllMocks();
+    jest.resetModules();
+  });
+
+  it('can connect and disconnect clients', () => {
+    const sut = new RealtimeNote('mock-note', 'nothing');
+    const client1 = mockConnection(true);
+    sut.addClient(client1);
+    expect(sut.getConnections()).toStrictEqual([client1]);
+    expect(sut.hasConnections()).toBeTruthy();
+    sut.removeClient(client1);
+    expect(sut.getConnections()).toStrictEqual([]);
+    expect(sut.hasConnections()).toBeFalsy();
+  });
+
+  it('creates a y-doc and y-awareness', () => {
+    const sut = new RealtimeNote('mock-note', 'nothing');
+    expect(sut.getYDoc()).toBe(mockedDoc);
+    expect(sut.getAwareness()).toBe(mockedAwareness);
+  });
+
+  it('destroys y-doc and y-awareness on self-destruction', () => {
+    const sut = new RealtimeNote('mock-note', 'nothing');
+    const docDestroy = jest.spyOn(mockedDoc, 'destroy');
+    const awarenessDestroy = jest.spyOn(mockedAwareness, 'destroy');
+    sut.destroy();
+    expect(docDestroy).toBeCalled();
+    expect(awarenessDestroy).toBeCalled();
+  });
+
+  it('emits destroy event on destruction', async () => {
+    const sut = new RealtimeNote('mock-note', 'nothing');
+    const destroyPromise = new Promise<void>((resolve) => {
+      sut.once('destroy', () => {
+        resolve();
+      });
+    });
+    sut.destroy();
+    await expect(destroyPromise).resolves.not.toThrow();
+  });
+
+  it("doesn't destroy a destroyed note", () => {
+    const sut = new RealtimeNote('mock-note', 'nothing');
+    sut.destroy();
+    expect(() => sut.destroy()).toThrow();
+  });
+});