diff --git a/tests/WebPlatformSubset/upstream-files.json b/tests/WebPlatformSubset/upstream-files.json
index 145216840..9026f2c9a 100644
--- a/tests/WebPlatformSubset/upstream-files.json
+++ b/tests/WebPlatformSubset/upstream-files.json
@@ -106,6 +106,9 @@
     "shadow-dom/Element-interface-shadowRoot-attribute.html": "d4e740808bfd51ae76593b05159943595baa127f7fa205054736c2e8aeef151a",
     "shadow-dom/HTMLSlotElement-interface.html": "5e15195914e8800dcc6fa6de88aaa184316c42d85fa31eea0190a3eeabb00d60",
     "shadow-dom/ShadowRoot-interface.html": "2332d49d844c3ac679ba3c4748bfee5d2a508d04763b9813e15666b05a323cf4",
-    "uievents/order-of-events/focus-events/focus-automated-blink-webkit.html": "8630aec2d53c1b890c205f40e49059b010fae1d729f0b721239f391395b169c1"
+    "uievents/order-of-events/focus-events/focus-automated-blink-webkit.html": "8630aec2d53c1b890c205f40e49059b010fae1d729f0b721239f391395b169c1",
+    "webmessaging/Channel_postMessage_clone_port_error.any.js": "48957061b1b6810b1c229c92e66b5dcdd829a8904c14b4460abb406dd75360de",
+    "webmessaging/message-channels/basics.any.js": "d5d60f5efbc3eb9a026ba44763fb19c2564f6a02a717ff28982e22d52143c69e",
+    "webmessaging/message-channels/close.any.js": "1ebab07ef56a6fd88b61b4a3af9c4c77d604a2ed950b5bd53d6334c5461895d9"
   }
 }
diff --git a/tests/WebPlatformSubset/upstream/webmessaging/Channel_postMessage_clone_port_error.any.js b/tests/WebPlatformSubset/upstream/webmessaging/Channel_postMessage_clone_port_error.any.js
new file mode 100644
index 000000000..cbee47270
--- /dev/null
+++ b/tests/WebPlatformSubset/upstream/webmessaging/Channel_postMessage_clone_port_error.any.js
@@ -0,0 +1,14 @@
+// META: title=postMessage() DataCloneError: cloning source port
+
+    var description = "Test Description: Throw a DataCloneError if transfer array in postMessage contains source port.";
+
+    test(function()
+    {
+        var channel = new MessageChannel();
+        channel.port1.start();
+
+        assert_throws_dom("DATA_CLONE_ERR", function()
+        {
+            channel.port1.postMessage("ports", [channel.port1]);
+        });
+    }, description);
diff --git a/tests/WebPlatformSubset/upstream/webmessaging/message-channels/basics.any.js b/tests/WebPlatformSubset/upstream/webmessaging/message-channels/basics.any.js
new file mode 100644
index 000000000..5732fb268
--- /dev/null
+++ b/tests/WebPlatformSubset/upstream/webmessaging/message-channels/basics.any.js
@@ -0,0 +1,12 @@
+// META: title=basic messagechannel test
+
+async_test(function(t) {
+  var channel = new MessageChannel();
+  channel.port1.postMessage(1);
+  channel.port2.onmessage = t.step_func(
+    function(e) {
+      assert_equals(e.data, 1);
+      t.done();
+    });
+  channel.port2.start();
+});
diff --git a/tests/WebPlatformSubset/upstream/webmessaging/message-channels/close.any.js b/tests/WebPlatformSubset/upstream/webmessaging/message-channels/close.any.js
new file mode 100644
index 000000000..8741d894b
--- /dev/null
+++ b/tests/WebPlatformSubset/upstream/webmessaging/message-channels/close.any.js
@@ -0,0 +1,62 @@
+// How long (in ms) these tests should wait before deciding no further messages
+// will be received.
+const time_to_wait_for_messages = 100;
+
+async_test(t => {
+    const c = new MessageChannel();
+    c.port1.onmessage = t.unreached_func('Should not have delivered message');
+    c.port1.close();
+    c.port2.postMessage('TEST');
+    setTimeout(t.step_func_done(), time_to_wait_for_messages);
+  }, 'Message sent to closed port should not arrive.');
+
+async_test(t => {
+    const c = new MessageChannel();
+    c.port1.onmessage = t.unreached_func('Should not have delivered message');
+    c.port2.close();
+    c.port2.postMessage('TEST');
+    setTimeout(t.step_func_done(), time_to_wait_for_messages);
+  }, 'Message sent from closed port should not arrive.');
+
+async_test(t => {
+    const c = new MessageChannel();
+    c.port1.onmessage = t.unreached_func('Should not have delivered message');
+    c.port1.close();
+    const c2 = new MessageChannel();
+    c2.port1.onmessage = t.step_func(e => {
+        e.ports[0].postMessage('TESTMSG');
+        setTimeout(t.step_func_done(), time_to_wait_for_messages);
+      });
+    c2.port2.postMessage('TEST', [c.port2]);
+  }, 'Message sent to closed port from transferred port should not arrive.');
+
+async_test(t => {
+    const c = new MessageChannel();
+    let isClosed = false;
+    c.port1.onmessage = t.step_func_done(e => {
+        assert_true(isClosed);
+        assert_equals(e.data, 'TEST');
+      });
+    c.port2.postMessage('TEST');
+    c.port2.close();
+    isClosed = true;
+  }, 'Inflight messages should be delivered even when sending port is closed afterwards.');
+
+async_test(t => {
+    const c = new MessageChannel();
+    c.port1.onmessage = t.step_func_done(e => {
+        if (e.data == 'DONE') t.done();
+        assert_equals(e.data, 'TEST');
+        c.port1.close();
+      });
+    c.port2.postMessage('TEST');
+    c.port2.postMessage('DONE');
+  }, 'Close in onmessage should not cancel inflight messages.');
+
+test(() => {
+  const c1 = new MessageChannel();
+  const c2 = new MessageChannel();
+  c1.port1.close();
+  assert_throws_dom("DataCloneError", () => c2.port1.postMessage(null, [c1.port1]));
+  c2.port1.postMessage(null, [c1.port2]);
+}, "close() detaches a MessagePort (but not the one its entangled with)");
diff --git a/tests/WebPlatformSubset/webscene-aureon-runtime-profile.json b/tests/WebPlatformSubset/webscene-aureon-runtime-profile.json
index c04ec0854..96a634e91 100644
--- a/tests/WebPlatformSubset/webscene-aureon-runtime-profile.json
+++ b/tests/WebPlatformSubset/webscene-aureon-runtime-profile.json
@@ -9,6 +9,40 @@
   },
   "required": [],
   "candidate": [
+    {
+      "path": "webmessaging/message-channels/basics.any.js",
+      "type": "testharness",
+      "capabilities": [
+        "window-any-js-harness",
+        "message-channel",
+        "message-port-start"
+      ],
+      "evidence": ["unchanged-pinned-wpt-messagechannel-basics"],
+      "reason": "Unchanged pinned WPT proving queued MessageChannel delivery after explicit MessagePort.start()."
+    },
+    {
+      "path": "webmessaging/Channel_postMessage_clone_port_error.any.js",
+      "type": "testharness",
+      "capabilities": [
+        "window-any-js-harness",
+        "messageport-transfer",
+        "structured-clone-error"
+      ],
+      "evidence": ["unchanged-pinned-wpt-messageport-transfer-error"],
+      "reason": "Unchanged pinned WPT requiring DataCloneError when a MessagePort attempts to transfer itself."
+    },
+    {
+      "path": "webmessaging/message-channels/close.any.js",
+      "type": "testharness",
+      "capabilities": [
+        "window-any-js-harness",
+        "message-port-close",
+        "messageport-transfer",
+        "inflight-message-delivery"
+      ],
+      "evidence": ["unchanged-pinned-wpt-messageport-close"],
+      "reason": "Unchanged pinned WPT covering closed-port suppression, transfer rejection, and delivery of messages queued before close()."
+    },
     {
       "path": "contracts/module-worker-clone.html",
       "type": "contract",