chore: Add test suite for multi-tab behaviour

jcoglan · jcoglan · commit 5d2955a0eb15 · 2026-03-27T16:57:32.000Z
diff --git a/.eslintrc.json b/.eslintrc.json
@@ -21,7 +21,8 @@
     "ArrayBuffer": "readonly",
     "FileReaderSync": "readonly",
     "emit": "readonly",
-    "PouchDB": "readonly"
+    "PouchDB": "readonly",
+    "__pouch__": "readonly"
   },
 
   "rules": {
diff --git a/tests/multitab/concurrency.test.js b/tests/multitab/concurrency.test.js
@@ -0,0 +1,42 @@
+'use strict';
+
+const { assert } = require('chai');
+const UserAgent = require('./user_agent');
+
+describe('multi-tab concurrency', () => {
+  let agent, res;
+
+  beforeEach(async () => {
+    agent = await UserAgent.start();
+  });
+
+  afterEach(async () => {
+    await agent.stop();
+  });
+
+  async function checkInfo({ doc_count }) {
+    let info1 = await agent.eval(1, () => __pouch__.info());
+    assert.equal(info1.doc_count, doc_count);
+
+    let info2 = await agent.eval(2, () => __pouch__.info());
+    assert.deepEqual(info1, info2);
+  }
+
+  it('creates docs concurrently in two tabs', async () => {
+    res = await agent.eval(1, () => __pouch__.put({ _id: 'doc-1' }));
+    assert(res.ok);
+    await checkInfo({ doc_count: 1 });
+
+    res = await agent.eval(2, () => __pouch__.put({ _id: 'doc-2' }));
+    assert(res.ok);
+    await checkInfo({ doc_count: 2 });
+
+    res = await agent.eval(1, () => __pouch__.put({ _id: 'doc-3' }));
+    assert(res.ok);
+    await checkInfo({ doc_count: 3 }); // fails on indexeddb; pages have different info
+
+    res = await agent.eval(2, () => __pouch__.put({ _id: 'doc-4' }));
+    assert(res.ok); // fails on indexeddb
+    await checkInfo({ doc_count: 4 });
+  });
+});
diff --git a/tests/multitab/shell.html b/tests/multitab/shell.html
@@ -0,0 +1,9 @@
+<!doctype html>
+<html>
+  <head>
+    <title>Playwright shell</title>
+    <script src="/packages/node_modules/pouchdb/dist/pouchdb.min.js"></script>
+    <script src="/packages/node_modules/pouchdb/dist/pouchdb.indexeddb.min.js"></script>
+  </head>
+  <body></body>
+</html>
diff --git a/tests/multitab/user_agent.js b/tests/multitab/user_agent.js
@@ -0,0 +1,53 @@
+'use strict';
+
+const playwright = require('playwright');
+
+const ADAPTERS = process.env.ADAPTERS || 'indexeddb';
+const CLIENT = process.env.CLIENT || 'firefox';
+const SHELL_URL = 'http://127.0.0.1:8000/tests/multitab/shell.html';
+
+class UserAgent {
+  static async start() {
+    let browser = await playwright[CLIENT].launch();
+    let context = await browser.newContext();
+    return new UserAgent(ADAPTERS, browser, context);
+  }
+
+  constructor(adapter, browser, context) {
+    this._adapter = adapter;
+    this._browser = browser;
+    this._context = context;
+    this._pages = new Map();
+  }
+
+  async stop() {
+    await this._browser.close();
+  }
+
+  async eval(pageId, fn) {
+    let page = await this._getPage(pageId);
+    return page.evaluate(fn);
+  }
+
+  _getPage(id) {
+    if (!this._pages.has(id)) {
+      this._pages.set(id, this._setupPage());
+    }
+    return this._pages.get(id);
+  }
+
+  async _setupPage() {
+    let page = await this._context.newPage();
+    await page.goto(SHELL_URL);
+
+    if (this._adapter === 'idb') {
+      await page.evaluate(() => window.__pouch__ = new PouchDB('testdb', { adapter: 'idb' }));
+    } else if (this._adapter === 'indexeddb') {
+      await page.evaluate(() => window.__pouch__ = new PouchDB('testdb', { adapter: 'indexeddb' }));
+    }
+
+    return page;
+  }
+}
+
+module.exports = UserAgent;
