♻️(backend) rename convert-markdown endpoint

Renamed the `convert-markdown` endpoint to `convert` as a
general-purpose conversion endpoint for integration with DocSpec
conversion (DOCX import), without altering its existing functionality.

In a future contribution, this endpoint will not only support conversion
from Markdown -> BlockNote -> Yjs but also directly BlockNote -> Yjs.

Signed-off-by: Stephan Meijer <me@stephanmeijer.com>

src/frontend/servers/y-provider/__tests__/convert.test.ts

@@ -0,0 +1,66 @@
+import request from 'supertest';
+
+const port = 5556;
+const origin = 'http://localhost:3000';
+
+jest.mock('../src/env', () => {
+  return {
+    PORT: port,
+    COLLABORATION_SERVER_ORIGIN: origin,
+    Y_PROVIDER_API_KEY: 'yprovider-api-key',
+  };
+});
+
+import { initServer } from '../src/servers/appServer';
+
+console.error = jest.fn();
+const { app, server } = initServer();
+
+describe('Server Tests', () => {
+  afterAll(() => {
+    server.close();
+  });
+
+  test('POST /api/convert with incorrect API key should return 403', async () => {
+    const response = await request(app as any)
+      .post('/api/convert')
+      .set('Origin', origin)
+      .set('Authorization', 'wrong-api-key');
+
+    expect(response.status).toBe(403);
+    expect(response.body.error).toBe('Forbidden: Invalid API Key');
+  });
+
+  test('POST /api/convert with a Bearer token', async () => {
+    const response = await request(app as any)
+      .post('/api/convert')
+      .set('Origin', origin)
+      .set('Authorization', 'Bearer test-secret-api-key');
+
+    // Warning: Changing the authorization header to Bearer token format will break backend compatibility with this microservice.
+    expect(response.status).toBe(403);
+  });
+
+  test('POST /api/convert with missing body param content', async () => {
+    const response = await request(app as any)
+      .post('/api/convert')
+      .set('Origin', origin)
+      .set('Authorization', 'yprovider-api-key');
+
+    expect(response.status).toBe(400);
+    expect(response.body.error).toBe('Invalid request: missing content');
+  });
+
+  test('POST /api/convert with body param content being an empty string', async () => {
+    const response = await request(app as any)
+      .post('/api/convert')
+      .set('Origin', origin)
+      .set('Authorization', 'yprovider-api-key')
+      .send({
+        content: '',
+      });
+
+    expect(response.status).toBe(400);
+    expect(response.body.error).toBe('Invalid request: missing content');
+  });
+});