Use nip.io to have a specific hostname for proxy

Also use GRIST_ORG_IN_PATH to make it work as expected, and
GRIST_SINGLE_PORT=0 to ensure to query the pool of workers.

test/server/lib/DocApi.ts

@@ -173,12 +173,14 @@ describe('DocApi', function () {
         const additionalEnvConfiguration = {
           ALLOWED_WEBHOOK_DOMAINS: `example.com,localhost:${webhooksTestPort}`,
           GRIST_DATA_DIR: dataDir,
-          APP_HOME_URL: await proxy.getServerUrl()
+          APP_HOME_URL: await proxy.getServerUrl(),
+          GRIST_ORG_IN_PATH: 'true',
+          GRIST_SINGLE_PORT: '0',
         };
         home = await TestServer.startServer('home', tmpDir, suitename, additionalEnvConfiguration);
         docs = await TestServer.startServer('docs', tmpDir, suitename, additionalEnvConfiguration, home.serverUrl);
 
-        proxy.start(home, docs);
+        await proxy.start(home, docs);
 
         homeUrl = serverUrl = await proxy.getServerUrl();
         iterateOverAccountHeaders(account => {
@@ -3182,8 +3184,9 @@ function testDocApi() {
   it("GET /docs/{did1}/compare/{did2} tracks changes between docs", async function () {
     // Pass kiwi's headers as it contains both Authorization and Origin headers
     // if run behind a proxy, so we can ensure that the Origin header check is not made.
+    const userApiServerUrl = docs.proxiedServer ? serverUrl : undefined;
     const chimpyApi = home.makeUserApi(
-      ORG_NAME, 'chimpy', { serverUrl, headers: chimpy.headers as Record<string, string> }
+      ORG_NAME, 'chimpy', { serverUrl: userApiServerUrl, headers: chimpy.headers as Record<string, string> }
     );
     const ws1 = (await chimpyApi.getOrgWorkspaces('current'))[0].id;
     const docId1 = await chimpyApi.newDoc({name: 'testdoc1'}, ws1);

test/server/lib/helpers/TestServer.ts

@@ -199,7 +199,12 @@ export class TestServer {
 
 // FIXME: found that TestProxyServer exist, what should I do? :'(
 export class TestServerProxy {
-  public static readonly HOSTNAME: string = 'grist-test-proxy.localhost';
+
+  // Use a different hostname for the proxy than the doc and home workers'
+  // so we can ensure that either we omit the Origin header (so the internal calls to home and doc workers
+  // are not considered as CORS requests), or otherwise we fail because the hostnames are different
+  // https://github.com/gristlabs/grist-core/blob/24b39c651b9590cc360cc91b587d3e1b301a9c63/app/server/lib/requestUtils.ts#L85-L98
+  public static readonly HOSTNAME: string = 'grist-test-proxy.127.0.0.1.nip.io';
 
   private _stopped: boolean = false;
   private _app = express();
@@ -210,18 +215,19 @@ export class TestServerProxy {
 
   public constructor() {
     this._address = new Promise(resolve => {
-      this._server = this._app.listen(0, TestServerProxy.HOSTNAME, () => {
+      this._server = this._app.listen(0, () => {
         resolve(this._server.address() as AddressInfo);
       });
     });
   }
 
-  public start(homeServer: TestServer, docServer: TestServer) {
+  public async start(homeServer: TestServer, docServer: TestServer) {
     this._app.all(['/dw/dw1', '/dw/dw1/*'], (oreq, ores) => this._getRequestHandlerFor(docServer));
     this._app.all('/*', this._getRequestHandlerFor(homeServer));
     // Forbid now the use of serverUrl property
     homeServer.disallowDirectAccess();
     docServer.disallowDirectAccess();
+    log.info('proxy server running on ', await this.getServerUrl());
   }
 
   public async getAddress() {
@@ -254,11 +260,11 @@ export class TestServerProxy {
         headers: oreq.headers,
       };
 
-      log.debug('[proxy] Requesting: ' + oreq.url);
+      log.debug(`[proxy] Requesting (method=${oreq.method}): ${new URL(oreq.url, serverUrl).href}`);
 
       const creq = http
       .request(options, pres => {
-        log.debug('[proxy] Received response for ' + pres.url);
+        log.debug('[proxy] Received response for ' + oreq.url);
 
         // set encoding, required?
         pres.setEncoding('utf8');