[BigSur wk1 Release arm64] imported/w3c/web-platform-tests/workers/modules/shared-worker-import-csp.html is a flaky failure

• Component: Service Workers
• Status: NEW ---

[Eric Hutchison]

imported/w3c/web-platform-tests/workers/modules/shared-worker-import-csp.html 

is a flaky failure on BigSur wk1 Release arm64 since test release on platform.

History: https://results.webkit.org/?suite=layout-tests&test=imported%2Fw3c%2Fweb-platform-tests%2Fworkers%2Fmodules%2Fshared-worker-import-csp.html&platform=ios&platform=mac

Diff: 

--- /Volumes/Data/worker/bigsur-release-applesilicon-tests-wk1/build/layout-test-results/imported/w3c/web-platform-tests/workers/modules/shared-worker-import-csp-expected.txt
+++ /Volumes/Data/worker/bigsur-release-applesilicon-tests-wk1/build/layout-test-results/imported/w3c/web-platform-tests/workers/modules/shared-worker-import-csp-actual.txt
@@ -14,15 +14,4 @@
 CONSOLE MESSAGE: ReferenceError: Can't find variable: SharedWorker
 CONSOLE MESSAGE: ReferenceError: Can't find variable: SharedWorker
 CONSOLE MESSAGE: ReferenceError: Can't find variable: SharedWorker
-CONSOLE MESSAGE: ReferenceError: Can't find variable: SharedWorker
 
-FAIL worker-src 'self' directive should disallow cross origin static import. assert_array_equals: value is object "[object Object]", expected array
-FAIL worker-src * directive should allow cross origin static import. assert_array_equals: value is object "[object Object]", expected array
-FAIL script-src 'self' directive should disallow cross origin static import. assert_array_equals: value is object "[object Object]", expected array
-FAIL script-src * directive should allow cross origin static import. assert_array_equals: value is object "[object Object]", expected array
-FAIL worker-src * directive should override script-src 'self' directive and allow cross origin static import. assert_array_equals: value is object "[object Object]", expected array
-FAIL worker-src 'self' directive should override script-src * directive and disallow cross origin static import. assert_array_equals: value is object "[object Object]", expected array
-FAIL script-src 'self' directive should disallow cross origin dynamic import. assert_array_equals: value is object "[object Object]", expected array
-FAIL script-src * directive should allow cross origin dynamic import. assert_array_equals: value is object "[object Object]", expected array
-FAIL worker-src 'self' directive should not take effect on dynamic import. assert_array_equals: value is object "[object Object]", expected array
-

Reproduced using run-webkit-tests -1 --iterations 500 --exit-after-n-failures 2 -f imported/w3c/web-platform-tests/workers/modules/shared-worker-import-csp.html on r280247

[Radar WebKit Bug Importer]

<rdar://problem/81034895>

[Eric Hutchison]

Updated test expectations on https://trac.webkit.org/changeset/280257/webkit.

[Chris Dumez]

Seems to have to do with the following code in LayoutTests/resources/testharnessreport.js:

```
// Wait for any other completion callbacks, which may eliminate test elements
// from the page and therefore reduce the output.
setTimeout(function () {
    testRunner.forceImmediateCompletion();
}, 0);
```

The 0 timer here seems to sometimes cause the test to finish before all the windows have closed (Test relies on `add_result_callback(() => win.close());`) and it affects the output.