chore: ensure `python@3.11` is installed for WPT tests (#23195)

This provides a more thorough check of whether the correct Python
version is installed for running WPT tests.

2 files changed, 3 insertions, 2 deletions

diff --git a/tests/wpt/runner/utils.ts b/tests/wpt/runner/utils.ts
index 5e3399fa7..47f980833 100644
--- a/tests/wpt/runner/utils.ts
+++ b/tests/wpt/runner/utils.ts
@@ -141,10 +141,10 @@ export async function checkPy3Available() {
   assert(success, "failed to run python --version");
   const output = new TextDecoder().decode(stdout);
   assert(
-    output.includes("Python 3."),
+    output.includes("Python 3.11"),
     `The ${
       Deno.build.os == "windows" ? "python.exe" : "python3"
-    } in your path is not Python 3.`,
+    } in your path is not Python 3.11.x. See https://github.com/web-platform-tests/wpt/issues/44427 for more details.`,
   );
 }
 
diff --git a/tests/wpt/wpt.ts b/tests/wpt/wpt.ts
index 35a7c1e79..056db5dc0 100755
--- a/tests/wpt/wpt.ts
+++ b/tests/wpt/wpt.ts
@@ -72,6 +72,7 @@ switch (command) {
     break;
 
   case "run":
+    await checkPy3Available();
     await cargoBuild();
     await run();
     break;