Add 'shadowrealm-in-audioworklet' global

This will add to any test with global=shadowrealm in its metadata, an
.any.shadowrealm-in-audioworklet.html variant.

The wrapper here is similar to the one for ServiceWorkers, since dynamic
import() is also forbidden in worklet scopes. But additionally fetch() is
not exposed, so we add a utility function to set up the ability to call
the window realm's fetch() through the AudioWorklet's message port.

We also add /resources/testharness-shadowrealm-audioworkletprocessor.js to
contain most of the AudioWorklet setup boilerplate, so that it isn't
written inline in serve.py.

Note '.https.' needs to be added to the test path.

docs/writing-tests/testharness.md

@@ -182,6 +182,9 @@ are:
 * `shadowrealm-in-serviceworker`: runs the test code in a ShadowRealm context
   hosted in a service worker; to be run at
   <code><var>x</var>.https.any.shadowrealm-in-serviceworker.html</code>
+* `shadowrealm-in-audioworklet`: runs the test code in a ShadowRealm context
+  hosted in an AudioWorklet processor; to be run at
+  <code><var>x</var>.https.any.shadowrealm-in-audioworklet.html</code>
 * `shadowrealm`: shorthand for all of the ShadowRealm scopes
 
 To check what scope your test is run from, you can use the following methods that will

resources/testharness-shadowrealm-audioworkletprocessor.js

@@ -0,0 +1,52 @@
+/**
+ * AudioWorkletProcessor intended for hosting a ShadowRealm and running a test
+ * inside of that ShadowRealm.
+ */
+globalThis.TestRunner = class TestRunner extends AudioWorkletProcessor {
+  constructor() {
+    super();
+    this.createShadowRealmAndStartTests();
+  }
+
+  /**
+   * Fetch adaptor function intended as a drop-in replacement for fetchAdaptor()
+   * (see testharness-shadowrealm-outer.js), but it does not assume fetch() is
+   * present in the realm. Instead, it relies on setupFakeFetchOverMessagePort()
+   * having been called on the port on the other side of this.port's channel.
+   */
+  fetchOverPortExecutor(resource) {
+    return (resolve, reject) => {
+      const listener = (event) => {
+        if (typeof event.data !== "string" || !event.data.startsWith("fetchResult::")) {
+          return;
+        }
+
+        const result = event.data.slice("fetchResult::".length);
+        if (result.startsWith("success::")) {
+          resolve(result.slice("success::".length));
+        } else {
+          reject(result.slice("fail::".length));
+        }
+
+        this.port.removeEventListener("message", listener);
+      }
+      this.port.addEventListener("message", listener);
+      this.port.start();
+      this.port.postMessage(`fetchRequest::${resource}`);
+    }
+  }
+
+  /**
+   * Async method, which is patched over in
+   * (test).any.audioworklet-shadowrealm.js; see serve.py
+   */
+  async createShadowRealmAndStartTests() {
+    throw new Error("Forgot to overwrite this method!");
+  }
+
+  /** Overrides AudioWorkletProcessor.prototype.process() */
+  process() {
+    return false;
+  }
+};
+registerProcessor("test-runner", TestRunner);

resources/testharness-shadowrealm-outer.js

@@ -100,3 +100,28 @@ globalThis.setupFakeDynamicImportInShadowRealm = function(realm, adaptor) {
     }
   `)(fetchModuleTextExecutor);
 };
+
+/**
+ * Used when the hosting realm does not expose fetch(), i.e. in worklets. The
+ * port on the other side of the channel needs to send messages starting with
+ * 'fetchRequest::' and listen for messages starting with 'fetchResult::'. See
+ * testharness-shadowrealm-audioworkletprocessor.js.
+ *
+ * @param {port} MessagePort - the message port on which to listen for fetch
+ *   requests
+ */
+globalThis.setupFakeFetchOverMessagePort = function (port) {
+  port.addEventListener("message", (event) => {
+    if (typeof event.data !== "string" || !event.data.startsWith("fetchRequest::")) {
+      return;
+    }
+
+    fetch(event.data.slice("fetchRequest::".length))
+      .then(res => res.text())
+      .then(
+        text => port.postMessage(`fetchResult::success::${text}`),
+        error => port.postMessage(`fetchResult::fail::${error}`),
+      );
+  });
+  port.start();
+}

tools/manifest/sourcefile.py

@@ -93,12 +93,17 @@ class VariantData(TypedDict, total=False):
         "force_https": True,
         "suffix": ".https.any.shadowrealm-in-serviceworker.html",
     },
+    "shadowrealm-in-audioworklet": {
+        "force_https": True,
+        "suffix": ".https.any.shadowrealm-in-audioworklet.html",
+    },
     "shadowrealm": {"longhand": {
         "shadowrealm-in-window",
         "shadowrealm-in-shadowrealm",
         "shadowrealm-in-dedicatedworker",
         "shadowrealm-in-sharedworker",
         "shadowrealm-in-serviceworker",
+        "shadowrealm-in-audioworklet",
     }},
     "jsshell": {"suffix": ".any.js"},
 }

tools/serve/serve.py

@@ -535,6 +535,33 @@ class ShadowRealmInServiceWorkerHandler(ServiceWorkersHandler):
                      ".any.serviceworker-shadowrealm.js")]
 
 
+class ShadowRealmInAudioWorkletHandler(HtmlWrapperHandler):
+    global_type = "shadowrealm-in-audioworklet"
+    path_replace = [(".https.any.shadowrealm-in-audioworklet.html", ".any.js",
+                     ".any.audioworklet-shadowrealm.js")]
+
+    wrapper = """<!doctype html>
+<meta charset=utf-8>
+%(meta)s
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/resources/testharness-shadowrealm-outer.js"></script>
+<script>
+(async function() {
+  const context = new AudioContext();
+  await context.audioWorklet.addModule(
+    "/resources/testharness-shadowrealm-outer.js");
+  await context.audioWorklet.addModule(
+    "/resources/testharness-shadowrealm-audioworkletprocessor.js");
+  await context.audioWorklet.addModule("%(path)s%(query)s");
+  const node = new AudioWorkletNode(context, "test-runner");
+  setupFakeFetchOverMessagePort(node.port);
+  fetch_tests_from_worker(node.port);
+})();
+</script>
+"""
+
+
 class BaseWorkerHandler(WrapperHandler):
     headers = [('Content-Type', 'text/javascript')]
 
@@ -654,6 +681,37 @@ def _create_script_import(self, attribute):
         return 'await fakeDynamicImport("%s");' % attribute
 
 
+class ShadowRealmAudioWorkletWrapperHandler(BaseWorkerHandler):
+    path_replace = [(".any.audioworklet-shadowrealm.js", ".any.js")]
+    wrapper = """%(meta)s
+TestRunner.prototype.createShadowRealmAndStartTests = async function() {
+  const queryPart = import.meta.url.split('?')[1];
+  const locationSearch = queryPart ? '?' + queryPart : '';
+
+  const r = new ShadowRealm();
+  const adaptor = this.fetchOverPortExecutor.bind(this);
+  setupFakeDynamicImportInShadowRealm(r, adaptor);
+
+  await shadowRealmEvalAsync(r, `
+    await fakeDynamicImport("/resources/testharness-shadowrealm-inner.js");
+    await fakeDynamicImport("/resources/testharness.js");
+  `);
+  r.evaluate("setShadowRealmGlobalProperties")(locationSearch, adaptor);
+
+  await shadowRealmEvalAsync(r, `
+    %(script)s
+    await fakeDynamicImport("%(path)s");
+  `);
+  const forwardMessage = (msgJSON) =>
+    this.port.postMessage(JSON.parse(msgJSON));
+  r.evaluate("begin_shadow_realm_tests")(forwardMessage);
+}
+"""
+
+    def _create_script_import(self, attribute):
+        return 'await fakeDynamicImport("%s");' % attribute
+
+
 rewrites = [("GET", "/resources/WebIDLParser.js", "/resources/webidl2/lib/webidl2.js")]
 
 
@@ -715,11 +773,13 @@ def add_mount_point(self, url_base, path):
             ("GET", "*.any.shadowrealm-in-dedicatedworker.html", ShadowRealmInDedicatedWorkerHandler),
             ("GET", "*.any.shadowrealm-in-sharedworker.html", ShadowRealmInSharedWorkerHandler),
             ("GET", "*.any.shadowrealm-in-serviceworker.html", ShadowRealmInServiceWorkerHandler),
+            ("GET", "*.any.shadowrealm-in-audioworklet.html", ShadowRealmInAudioWorkletHandler),
             ("GET", "*.any.window-module.html", WindowModulesHandler),
             ("GET", "*.any.worker.js", ClassicWorkerHandler),
             ("GET", "*.any.worker-module.js", ModuleWorkerHandler),
             ("GET", "*.any.serviceworker-shadowrealm.js", ShadowRealmServiceWorkerWrapperHandler),
             ("GET", "*.any.worker-shadowrealm.js", ShadowRealmWorkerWrapperHandler),
+            ("GET", "*.any.audioworklet-shadowrealm.js", ShadowRealmAudioWorkletWrapperHandler),
             ("GET", "*.asis", handlers.AsIsHandler),
             ("*", "/.well-known/attribution-reporting/report-event-attribution", handlers.PythonScriptHandler),
             ("*", "/.well-known/attribution-reporting/debug/report-event-attribution", handlers.PythonScriptHandler),