tests: generate and upload wptreport.json (#10869)

These reports can be consumed by tools like `wptreport` or
https://wpt.fyi. The old style report could be removed in a future PR
when wpt.deno.land is updated.

1 files changed, 8 insertions, 1 deletions

diff --git a/tools/wpt/testharnessreport.js b/tools/wpt/testharnessreport.js
index d3e783376..04251c852 100644
--- a/tools/wpt/testharnessreport.js
+++ b/tools/wpt/testharnessreport.js
@@ -10,6 +10,13 @@ window.add_result_callback(({ message, name, stack, status }) => {
   }
 });
 
-window.add_completion_callback((_tests, _harnessStatus) => {
+window.add_completion_callback((_tests, harnessStatus) => {
+  const data = new TextEncoder().encode(
+    `#$#$#${JSON.stringify(harnessStatus)}\n`,
+  );
+  let bytesWritten = 0;
+  while (bytesWritten < data.byteLength) {
+    bytesWritten += Deno.stderr.writeSync(data.subarray(bytesWritten));
+  }
   Deno.exit(0);
 });