add typing-extensions to pyodide, add comment about V8 bug

Author: samuelcolvin

wasm-preview/README.md

@@ -1,12 +1,11 @@
 # Demonstration of pydantic-core unit tests running in the browser
 
-To run tests in your browser, go
-[here](https://githubproxy.samuelcolvin.workers.dev/pydantic/pydantic-core/blob/main/wasm-preview/index.html).
+To run tests in your browser, go [here](https://githubproxy.samuelcolvin.workers.dev/pydantic/pydantic-core/blob/main/wasm-preview/index.html).
 
-To test with a specific version of pydantic-core, add a query parameter `?pydantic_core_version=...` to the URL,
-e.g. `?pydantic_core_version=v0.25.0`, defaults to latest release.
+To test with a specific version of pydantic-core, add a query parameter `?pydantic_core_version=...` to the URL, e.g. `?pydantic_core_version=v0.25.0`, defaults to latest release.
 
-This doesn't work for version of pydantic-core before v0.23.0 as before that we built 3.10 binaries, and pyodide
-now rust 3.11.
+This doesn't work for version of pydantic-core before v0.23.0 as before that we built 3.10 binaries, and pyodide now rust 3.11.
 
 If the output appears to stop prematurely, try looking in the developer console for more details.
+
+Tests are currently failing 10-15% of the wait through on Chrome due to a suspected V8 bug, see [pyodide/pyodide#3792](https://github.com/pyodide/pyodide/issues/3792) for more information.

wasm-preview/worker.js

@@ -97,7 +97,7 @@ async function main() {
     setupStreams(FS, pyodide._module.TTY);
     FS.mkdir('/test_dir');
     FS.chdir('/test_dir');
-    await pyodide.loadPackage(['micropip', 'pytest', 'pytz']);
+    await pyodide.loadPackage(['micropip', 'pytest', 'pytz', 'typing-extensions']);
     await pyodide.runPythonAsync(python_code, {globals: pyodide.toPy({pydantic_core_version, tests_zip})});
     post();
   } catch (err) {