Fix flaky playwright tests (#28984)

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

playwright/plugins/homeserver/synapse/legacyOAuthHomeserver.ts

@@ -6,20 +6,31 @@ SPDX-License-Identifier: AGPL-3.0-only OR GPL-3.0-only OR LicenseRef-Element-Com
 Please see LICENSE files in the repository root for full details.
 */
 
-import { Fixtures } from "@playwright/test";
+import { Fixtures, PlaywrightTestArgs } from "@playwright/test";
 import { TestContainers } from "testcontainers";
 
 import { Services } from "../../../services.ts";
 import { OAuthServer } from "../../oauth_server";
 
-export const legacyOAuthHomeserver: Fixtures<{}, Services> = {
-    _homeserver: [
-        async ({ _homeserver: container }, use) => {
+export const legacyOAuthHomeserver: Fixtures<PlaywrightTestArgs, Services, PlaywrightTestArgs> = {
+    oAuthServer: [
+        // eslint-disable-next-line no-empty-pattern
+        async ({}, use) => {
             const server = new OAuthServer();
-            const port = server.start();
-
+            await use(server);
+            server.stop();
+        },
+        { scope: "worker" },
+    ],
+    context: async ({ context, oAuthServer }, use, testInfo) => {
+        oAuthServer.onTestStarted(testInfo);
+        await use(context);
+    },
+    _homeserver: [
+        async ({ oAuthServer, _homeserver: homeserver }, use) => {
+            const port = oAuthServer.start();
             await TestContainers.exposeHostPorts(port);
-            container.withConfig({
+            homeserver.withConfig({
                 oidc_providers: [
                     {
                         idp_id: "test",
@@ -43,8 +54,8 @@ export const legacyOAuthHomeserver: Fixtures<{}, Services> = {
                     },
                 ],
             });
-            await use(container);
-            server.stop();
+
+            await use(homeserver);
         },
         { scope: "worker" },
     ],

playwright/plugins/oauth_server/index.ts

@@ -9,12 +9,21 @@ Please see LICENSE files in the repository root for full details.
 import http from "http";
 import express from "express";
 import { AddressInfo } from "net";
+import { TestInfo } from "@playwright/test";
+
+import { randB64Bytes } from "../utils/rand.ts";
 
 export class OAuthServer {
     private server?: http.Server;
+    private sub?: string;
+
+    public onTestStarted(testInfo: TestInfo): void {
+        this.sub = testInfo.testId;
+    }
 
     public start(): number {
         if (this.server) this.stop();
+        const token = randB64Bytes(16);
 
         const app = express();
 
@@ -28,7 +37,7 @@ export class OAuthServer {
             const code = req.body.code;
             if (code === "valid_auth_code") {
                 res.send({
-                    access_token: "oauth_access_token",
+                    access_token: token,
                     token_type: "Bearer",
                     expires_in: "3600",
                 });
@@ -43,7 +52,7 @@ export class OAuthServer {
 
             // return an OAuth2 user info object
             res.send({
-                sub: "alice",
+                sub: this.sub,
                 name: "Alice",
             });
         });