[ iOS MacOS ] imported/w3c/web-platform-tests/encoding/sharedarraybuffer.https.html is a flaky failure

imported/w3c/web-platform-tests/encoding/sharedarraybuffer.https.html

Is a flaky failure on iOS (Release & Debug) and MacOS Debug.

History: https://results.webkit.org/?suite=layout-tests&test=imported/w3c/web-platform-tests/encoding/sharedarraybuffer.https.html

The test started showing up on EWS as a flaky test.

https://ews-build.webkit.org/#/builders/51/builds/19853

Result page: https://build.webkit.org/results/Apple-BigSur-Debug-WK2-Tests/r281618%20(3440)/results.html

Diff:

--- /Volumes/Data/worker/bigsur-debug-tests-wk2/build/layout-test-results/imported/w3c/web-platform-tests/encoding/sharedarraybuffer.https-expected.txt
+++ /Volumes/Data/worker/bigsur-debug-tests-wk2/build/layout-test-results/imported/w3c/web-platform-tests/encoding/sharedarraybuffer.https-actual.txt
@@ -1,5 +1,5 @@
-
-FAIL decoding SharedArrayBuffer assert_throws_js: constructing TextDecoder with SharedArrayBuffer view should throw function "() => {
-    decoder.decode(new Uint8Array(buffer));
-  }" did not throw
-
+layer at (0,0) size 800x600
+  RenderView at (0,0) size 800x600
+layer at (0,0) size 800x600
+  RenderBlock {HTML} at (0,0) size 800x600
+    RenderBody {BODY} at (8,8) size 784x584

[Radar WebKit Bug Importer]

<rdar://problem/82393158>

This bug might have to same root case as https://bugs.webkit.org/show_bug.cgi?id=229501 since the diff, history, and affected configuration look very similar.

Updated test expectations: https://trac.webkit.org/changeset/281626/webkit

[Chris Dumez]

(In reply to ayumi_kojima from comment #2)
> This bug might have to same root case as
> https://bugs.webkit.org/show_bug.cgi?id=229501 since the diff, history, and
> affected configuration look very similar.

Yes, this is very likely the same issue. I suspect WebKitTestRunner's injected bundle doesn't deal well with process swaps on network response (due to COOP).

*** This bug has been marked as a duplicate of bug 229501 ***