diff --git a/tests/wpt/metadata/MANIFEST.json b/tests/wpt/metadata/MANIFEST.json
index 0c8f83804595..545cc63b1f1e 100644
--- a/tests/wpt/metadata/MANIFEST.json
+++ b/tests/wpt/metadata/MANIFEST.json
@@ -262509,6 +262509,11 @@
      {}
     ]
    ],
+   "css/css-properties-values-api/resources/utils.js": [
+    [
+     {}
+    ]
+   ],
    "css/css-properties-values-api/support/alt/alt.css": [
     [
      {}
@@ -304389,6 +304394,11 @@
      {}
     ]
    ],
+   "service-workers/service-worker/resources/enable-client-message-queue.html": [
+    [
+     {}
+    ]
+   ],
    "service-workers/service-worker/resources/end-to-end-worker.js": [
     [
      {}
@@ -304864,6 +304874,11 @@
      {}
     ]
    ],
+   "service-workers/service-worker/resources/message-vs-microtask.html": [
+    [
+     {}
+    ]
+   ],
    "service-workers/service-worker/resources/mime-sniffing-worker.js": [
     [
      {}
@@ -304944,6 +304959,11 @@
      {}
     ]
    ],
+   "service-workers/service-worker/resources/nested-iframe-parent.html": [
+    [
+     {}
+    ]
+   ],
    "service-workers/service-worker/resources/nested_load_worker.js": [
     [
      {}
@@ -305329,6 +305349,11 @@
      {}
     ]
    ],
+   "service-workers/service-worker/resources/stalling-service-worker.js": [
+    [
+     {}
+    ]
+   ],
    "service-workers/service-worker/resources/success.py": [
     [
      {}
@@ -328133,6 +328158,12 @@
      {}
     ]
    ],
+   "background-fetch/abort.https.window.js": [
+    [
+     "/background-fetch/abort.https.window.html",
+     {}
+    ]
+   ],
    "background-fetch/content-security-policy.https.window.js": [
     [
      "/background-fetch/content-security-policy.https.window.html",
@@ -337499,6 +337530,12 @@
      {}
     ]
    ],
+   "css/css-properties-values-api/self-utils.html": [
+    [
+     "/css/css-properties-values-api/self-utils.html",
+     {}
+    ]
+   ],
    "css/css-properties-values-api/typedom.tentative.html": [
     [
      "/css/css-properties-values-api/typedom.tentative.html",
@@ -443900,12 +443937,16 @@
    "8ce9f8faa2acdfe7a2ef8dfc6c1ad8cbdf01c72d",
    "support"
   ],
+  "background-fetch/abort.https.window.js": [
+   "db01bf94b85fe9aeb05c63ec02186bbb40ec8206",
+   "testharness"
+  ],
   "background-fetch/content-security-policy.https.window.js": [
    "0b5b1cb5e94d3f27bebbb5a462bf1e823dfc57b4",
    "testharness"
   ],
   "background-fetch/fetch.https.window.js": [
-   "77297186ca456148c94ce3375434673aa54a90de",
+   "9ed7e94da3bf7fc6cba5690813848ed269bfe8eb",
    "testharness"
   ],
   "background-fetch/get-ids.https.window.js": [
@@ -443945,7 +443986,7 @@
    "support"
   ],
   "background-fetch/service_workers/sw.js": [
-   "af4655dbad4ef6ad6b17d79bb2645aee98ce1102",
+   "2e3fbfff1a83e2d1f4aa40e738fa305a6eba513c",
    "support"
   ],
   "background-fetch/update-ui.https.window.js": [
@@ -553705,7 +553746,7 @@
    "testharness"
   ],
   "css/css-properties-values-api/registered-property-computation.html": [
-   "30d6b4bd609bf01f1bb10a485baa787f22b635dc",
+   "cbcc0bea64d47a296adff0759cb91509ecb5beb4",
    "testharness"
   ],
   "css/css-properties-values-api/registered-property-cssom.html": [
@@ -553716,6 +553757,14 @@
    "d655af661f7fd95ed0289cddb9c5546467d28592",
    "testharness"
   ],
+  "css/css-properties-values-api/resources/utils.js": [
+   "c4dc3fd5a8d98106395e3e99566f05d6d9a30c0c",
+   "support"
+  ],
+  "css/css-properties-values-api/self-utils.html": [
+   "530c5f677ad25858a06281a9e526584e57081af5",
+   "testharness"
+  ],
   "css/css-properties-values-api/support/alt/alt.css": [
    "aeb6ad5abe0e2b7423b90b0d94ad11dae74e11b7",
    "support"
@@ -594553,7 +594602,7 @@
    "support"
   ],
   "docs/_running-tests/safari.md": [
-   "e6cedd97f965fe0848df5b29efe6fd32257b79d1",
+   "3ef508d3780aae433100702f03bdac9f33190c62",
    "support"
   ],
   "docs/_writing-tests/ahem.md": [
@@ -599853,7 +599902,7 @@
    "testharness"
   ],
   "fetch/api/abort/serviceworker-intercepted.https.html": [
-   "623036d46639fe5aac8a5d5f5bdd9695d2a24dac",
+   "a88aa896c90bd30dde2800ad5fe428b2410bdec9",
    "testharness"
   ],
   "fetch/api/basic/accept-header.any.js": [
@@ -600333,7 +600382,7 @@
    "support"
   ],
   "fetch/api/request/destination/resources/fetch-destination-worker-no-load-event.js": [
-   "5a3c679cc03e4694e92051f32b1e7c797ecaff05",
+   "c1b6c506e957198c97db679c7d25e93952af3376",
    "support"
   ],
   "fetch/api/request/destination/resources/fetch-destination-worker.js": [
@@ -604645,7 +604694,7 @@
    "testharness"
   ],
   "html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-tokenization-noopener.html": [
-   "cac23648ade4c11a4fca671823a6064dbe697652",
+   "c31e75fdf57e1d35d45afceb24ab2216dfbfe483",
    "testharness"
   ],
   "html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-tokenization-screenx-screeny.html": [
@@ -622117,7 +622166,7 @@
    "support"
   ],
   "interfaces/web-animations.idl": [
-   "7dce1002e666d3efa9b18531e05b087f0f4adc0d",
+   "9a3579da75f23c33512b12e631f24a365080363e",
    "support"
   ],
   "interfaces/web-bluetooth.idl": [
@@ -622129,7 +622178,7 @@
    "support"
   ],
   "interfaces/web-share.idl": [
-   "36ffa43e37971adc75017cb5e80a9fe98552227e",
+   "7fa83b0fed51fa17c6e10b5ce065558d314d2f70",
    "support"
   ],
   "interfaces/webaudio.idl": [
@@ -634385,7 +634434,7 @@
    "testharness"
   ],
   "picture-in-picture/resources/picture-in-picture-helpers.js": [
-   "96972dcbc8ef07aa7ea0150c4ee645507eea0856",
+   "7561944a18d0296b33dbb3acb1f3a82b1512d08f",
    "support"
   ],
   "picture-in-picture/shadow-dom.html": [
@@ -643697,7 +643746,7 @@
    "testharness"
   ],
   "resource-timing/resource_timing_buffer_full_eventually.html": [
-   "7ca8237b02cc398786d78dd61aea3dcb1163d48a",
+   "ce745237c0657c7045b00d9c7b8e71770ed490fc",
    "testharness"
   ],
   "resource-timing/resource_timing_buffer_full_when_populate_entries.html": [
@@ -647213,7 +647262,7 @@
    "testharness"
   ],
   "service-workers/service-worker/postmessage-to-client.https.html": [
-   "15d2e889337078869e3c3e97d312649e6a8bd8b2",
+   "b1dc41a018f273832f4ac90c17b4b981f095b0ef",
    "testharness"
   ],
   "service-workers/service-worker/postmessage.https.html": [
@@ -647329,7 +647378,7 @@
    "support"
   ],
   "service-workers/service-worker/resources/about-blank-replacement-ping-frame.py": [
-   "58fb4403f9c6597d2707b1e3241155fec07189a8",
+   "bb07c241ad49a7535ba62ee8664a75c8c59cd64c",
    "support"
   ],
   "service-workers/service-worker/resources/about-blank-replacement-popup-frame.py": [
@@ -647556,6 +647605,10 @@
    "e69de29bb2d1d6434b8b29ae775ad8c2e48c5391",
    "support"
   ],
+  "service-workers/service-worker/resources/enable-client-message-queue.html": [
+   "512bd14bc67d46b902e68eb8773107de529cc798",
+   "support"
+  ],
   "service-workers/service-worker/resources/end-to-end-worker.js": [
    "d45a50556a93c7e38d94ac05b90d2d733c04896a",
    "support"
@@ -647936,6 +647989,10 @@
    "501521ff3e37dfc75bc61f3213c8282410f91fbe",
    "support"
   ],
+  "service-workers/service-worker/resources/message-vs-microtask.html": [
+   "2c45c59a475ae9b2e6bc168dc75b31eab9d231f4",
+   "support"
+  ],
   "service-workers/service-worker/resources/mime-sniffing-worker.js": [
    "046628055e15ca7291a14247efb560460d01ae24",
    "support"
@@ -648000,6 +648057,10 @@
    "8539b40066dd91bbfaf7ef240b8104dcb2ab3b27",
    "support"
   ],
+  "service-workers/service-worker/resources/nested-iframe-parent.html": [
+   "115ab26e1221024b30313569f484942b10f6dba0",
+   "support"
+  ],
   "service-workers/service-worker/resources/nested_load_worker.js": [
    "6e2e9edc4d8b35e03f5aa4b29966812addf43444",
    "support"
@@ -648308,6 +648369,10 @@
    "7341132745be2bee9e47114cda4167865e8a9699",
    "support"
   ],
+  "service-workers/service-worker/resources/stalling-service-worker.js": [
+   "fdf1e6cac04e1651f30d960897da8740a40c9138",
+   "support"
+  ],
   "service-workers/service-worker/resources/success.py": [
    "bcbb487d2b29d4ef089a6c7dc18e1cc166a262fc",
    "support"
@@ -658833,7 +658898,7 @@
    "support"
   ],
   "tools/wpt/browser.py": [
-   "3b3074a985607abfdb1bd125f3803e25acf7822d",
+   "51f0dbdba926550725ec4d42bc69cd69106bd19d",
    "support"
   ],
   "tools/wpt/commands.json": [
@@ -658841,7 +658906,7 @@
    "support"
   ],
   "tools/wpt/install.py": [
-   "62c833aa3f0c707e659f691be7a166d8f7ec43d8",
+   "f588a412845848b896a063e50f07cd0e3e0758e7",
    "support"
   ],
   "tools/wpt/markdown.py": [
@@ -658857,7 +658922,7 @@
    "support"
   ],
   "tools/wpt/run.py": [
-   "d9a44fd3711563a0134ad2fbfc2ee90ac73c6fbd",
+   "da01a816974bfe445967faeaf3855ab5dcb0cf33",
    "support"
   ],
   "tools/wpt/testfiles.py": [
@@ -658945,7 +659010,7 @@
    "support"
   ],
   "tools/wptrunner/requirements.txt": [
-   "0e71ed50411b6697198d2b19787506ff959d7e11",
+   "2ae1622a6a398b65cf43a37bca8962bf7d3196a4",
    "support"
   ],
   "tools/wptrunner/requirements_chrome.txt": [
@@ -659581,7 +659646,7 @@
    "support"
   ],
   "tools/wptserve/tests/functional/base.py": [
-   "f8331f5086d31730a8b86c0b708162d8e505f30d",
+   "190e385f1020a7a5184fa34ad5bd59a75920a15c",
    "support"
   ],
   "tools/wptserve/tests/functional/docroot/document.txt": [
@@ -659709,7 +659774,7 @@
    "support"
   ],
   "tools/wptserve/tests/functional/test_pipes.py": [
-   "fdac4537d64fb5d9c1fb8dd3e148cac7c5ec240a",
+   "693cb82e2410b6a66ce15085fb91218f04eb683c",
    "support"
   ],
   "tools/wptserve/tests/functional/test_request.py": [
@@ -665337,7 +665402,7 @@
    "testharness"
   ],
   "webrtc/RTCDTMFSender-helper.js": [
-   "1dd2bccb361d4baefc18d33252c15e6d984caeed",
+   "84cc771dda283da81a0568fe58ad52a77a262347",
    "support"
   ],
   "webrtc/RTCDTMFSender-insertDTMF.https.html": [
@@ -665349,7 +665414,7 @@
    "testharness"
   ],
   "webrtc/RTCDTMFSender-ontonechange.https.html": [
-   "6beefb5287d65f5bf90b5866e0881f6d8de385fb",
+   "ff6d117b3c75dde71cc52b4087f223477ad08bb4",
    "testharness"
   ],
   "webrtc/RTCDataChannel-bufferedAmount.html": [
diff --git a/tests/wpt/metadata/css/css-transitions/transitions-animatable-properties-01.html.ini b/tests/wpt/metadata/css/css-transitions/transitions-animatable-properties-01.html.ini
index 97a457d28979..98c044f3c1a9 100644
--- a/tests/wpt/metadata/css/css-transitions/transitions-animatable-properties-01.html.ini
+++ b/tests/wpt/metadata/css/css-transitions/transitions-animatable-properties-01.html.ini
@@ -71,6 +71,3 @@
   [bottom intermediate]
     expected: FAIL
 
-  [border-bottom-width end]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata/fetch/cross-origin-resource-policy/fetch-in-iframe.html.ini b/tests/wpt/metadata/fetch/cross-origin-resource-policy/fetch-in-iframe.html.ini
index 3951cd266d51..0d630fb814a5 100644
--- a/tests/wpt/metadata/fetch/cross-origin-resource-policy/fetch-in-iframe.html.ini
+++ b/tests/wpt/metadata/fetch/cross-origin-resource-policy/fetch-in-iframe.html.ini
@@ -1,4 +1,5 @@
 [fetch-in-iframe.html]
+  expected: CRASH
   [Untitled]
     expected: FAIL
 
diff --git a/tests/wpt/metadata/html/browsers/history/the-history-interface/traverse_the_history_1.html.ini b/tests/wpt/metadata/html/browsers/history/the-history-interface/traverse_the_history_1.html.ini
deleted file mode 100644
index 87b07c3e6704..000000000000
--- a/tests/wpt/metadata/html/browsers/history/the-history-interface/traverse_the_history_1.html.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[traverse_the_history_1.html]
-  [Multiple history traversals from the same task]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata/html/browsers/history/the-history-interface/traverse_the_history_5.html.ini b/tests/wpt/metadata/html/browsers/history/the-history-interface/traverse_the_history_5.html.ini
deleted file mode 100644
index dc2e45516deb..000000000000
--- a/tests/wpt/metadata/html/browsers/history/the-history-interface/traverse_the_history_5.html.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[traverse_the_history_5.html]
-  [Multiple history traversals, last would be aborted]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-tokenization-noopener.html.ini b/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-tokenization-noopener.html.ini
index 2fa1da41f33e..a0ce96f63e12 100644
--- a/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-tokenization-noopener.html.ini
+++ b/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-tokenization-noopener.html.ini
@@ -5,3 +5,6 @@
   [invalid feature names should not tokenize as "noopener"]
     expected: FAIL
 
+  [Integer value of 0 should not activate the feature]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata/html/semantics/embedded-content/the-img-element/environment-changes/viewport-change.html.ini b/tests/wpt/metadata/html/semantics/embedded-content/the-img-element/environment-changes/viewport-change.html.ini
index 6a2b93b1aa8c..12dfe8f5c8e7 100644
--- a/tests/wpt/metadata/html/semantics/embedded-content/the-img-element/environment-changes/viewport-change.html.ini
+++ b/tests/wpt/metadata/html/semantics/embedded-content/the-img-element/environment-changes/viewport-change.html.ini
@@ -11,7 +11,7 @@
     expected: TIMEOUT
 
   [picture: source (max-width:500px) valid image, img valid image, resize to narrow]
-    expected: TIMEOUT
+    expected: FAIL
 
   [img (srcset 1 cand) valid image, resize to wide]
     expected: FAIL
@@ -22,3 +22,12 @@
   [picture: source (max-width:500px) valid image, img broken image, resize to wide]
     expected: FAIL
 
+  [picture: source (max-width:500px) broken image, img valid image, resize to narrow]
+    expected: FAIL
+
+  [img (srcset 1 cand) valid image, resize to narrow]
+    expected: FAIL
+
+  [picture: same URL in source (max-width:500px) and img, resize to narrow]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata/html/semantics/embedded-content/the-img-element/non-active-document.html.ini b/tests/wpt/metadata/html/semantics/embedded-content/the-img-element/non-active-document.html.ini
deleted file mode 100644
index 8cc42056d34e..000000000000
--- a/tests/wpt/metadata/html/semantics/embedded-content/the-img-element/non-active-document.html.ini
+++ /dev/null
@@ -1,10 +0,0 @@
-[non-active-document.html]
-  [DOMParser]
-    expected: FAIL
-
-  [createHTMLDocument]
-    expected: FAIL
-
-  [<template>]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata/html/syntax/parsing/DOMContentLoaded-defer.html.ini b/tests/wpt/metadata/html/syntax/parsing/DOMContentLoaded-defer.html.ini
deleted file mode 100644
index a9677391662b..000000000000
--- a/tests/wpt/metadata/html/syntax/parsing/DOMContentLoaded-defer.html.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[DOMContentLoaded-defer.html]
-  [The end: DOMContentLoaded and defer scripts]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata/html/webappapis/dynamic-markup-insertion/opening-the-input-stream/aborted-parser.window.js.ini b/tests/wpt/metadata/html/webappapis/dynamic-markup-insertion/opening-the-input-stream/aborted-parser.window.js.ini
index c6d49957c4a3..ce482a60da89 100644
--- a/tests/wpt/metadata/html/webappapis/dynamic-markup-insertion/opening-the-input-stream/aborted-parser.window.js.ini
+++ b/tests/wpt/metadata/html/webappapis/dynamic-markup-insertion/opening-the-input-stream/aborted-parser.window.js.ini
@@ -2,3 +2,6 @@
   [document.open() after parser is aborted]
     expected: FAIL
 
+  [async document.open() after parser is aborted]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata/quirks/unitless-length/quirks.html.ini b/tests/wpt/metadata/quirks/unitless-length/quirks.html.ini
deleted file mode 100644
index 2ed601c6ff44..000000000000
--- a/tests/wpt/metadata/quirks/unitless-length/quirks.html.ini
+++ /dev/null
@@ -1,283 +0,0 @@
-[quirks.html]
-  [top: -\\31 .5]
-    expected: FAIL
-
-  [bottom: -1A]
-    expected: FAIL
-
-  [bottom: -1a]
-    expected: FAIL
-
-  [top: @1]
-    expected: FAIL
-
-  [top: "1a"]
-    expected: FAIL
-
-  [top: @a]
-    expected: FAIL
-
-  [bottom: "1"]
-    expected: FAIL
-
-  [bottom: -/**/1]
-    expected: FAIL
-
-  [top: +/**/1]
-    expected: FAIL
-
-  [bottom: @1a]
-    expected: FAIL
-
-  [top: 1\\31 ]
-    expected: FAIL
-
-  [top: url('1')]
-    expected: FAIL
-
-  [bottom: -\\31 ]
-    expected: FAIL
-
-  [top: calc(1)]
-    expected: FAIL
-
-  [top: \\31 ]
-    expected: FAIL
-
-  [bottom: +1\\31 ]
-    expected: FAIL
-
-  [bottom: 1\\31 .5]
-    expected: FAIL
-
-  [bottom: #0001]
-    expected: FAIL
-
-  [top: calc(2 * 2px)]
-    expected: FAIL
-
-  [bottom: 1a]
-    expected: FAIL
-
-  [bottom: A]
-    expected: FAIL
-
-  [bottom: #01]
-    expected: FAIL
-
-  [top: +\\31 .5]
-    expected: FAIL
-
-  [bottom: #1]
-    expected: FAIL
-
-  [top: -/**/1]
-    expected: FAIL
-
-  [bottom: +\\31 .5]
-    expected: FAIL
-
-  [bottom: \\31 ]
-    expected: FAIL
-
-  [bottom: calc(1)]
-    expected: FAIL
-
-  [top: #001]
-    expected: FAIL
-
-  [top: +\\31 ]
-    expected: FAIL
-
-  [bottom: +\\31 ]
-    expected: FAIL
-
-  [top: +1.5]
-    expected: FAIL
-
-  [top: +1\\31 ]
-    expected: FAIL
-
-  [bottom: @a]
-    expected: FAIL
-
-  [bottom: @1]
-    expected: FAIL
-
-  [top: #1]
-    expected: FAIL
-
-  [top: 1a]
-    expected: FAIL
-
-  [bottom: +1a]
-    expected: FAIL
-
-  [bottom: +1A]
-    expected: FAIL
-
-  [bottom: "a"]
-    expected: FAIL
-
-  [top: #00001]
-    expected: FAIL
-
-  [bottom: -1\\31 .5]
-    expected: FAIL
-
-  [top: "1"]
-    expected: FAIL
-
-  [bottom: 1.5]
-    expected: FAIL
-
-  [bottom: -\\31 .5]
-    expected: FAIL
-
-  [bottom: url('1')]
-    expected: FAIL
-
-  [bottom: -1.5]
-    expected: FAIL
-
-  [top: \\31 .5]
-    expected: FAIL
-
-  [bottom: "1a"]
-    expected: FAIL
-
-  [bottom: calc(2 * 2px)]
-    expected: FAIL
-
-  [bottom: +1\\31 .5]
-    expected: FAIL
-
-  [bottom: 1\\31 ]
-    expected: FAIL
-
-  [bottom: +/**/1]
-    expected: FAIL
-
-  [bottom: #00001]
-    expected: FAIL
-
-  [top: url(1)]
-    expected: FAIL
-
-  [bottom: #001]
-    expected: FAIL
-
-  [top: +1\\31 .5]
-    expected: FAIL
-
-  [top: -1a]
-    expected: FAIL
-
-  [top: -1A]
-    expected: FAIL
-
-  [bottom: url(1)]
-    expected: FAIL
-
-  [top: a]
-    expected: FAIL
-
-  [top: A]
-    expected: FAIL
-
-  [top: #000001]
-    expected: FAIL
-
-  [top: 1]
-    expected: FAIL
-
-  [top: 1\\31 .5]
-    expected: FAIL
-
-  [bottom: a]
-    expected: FAIL
-
-  [bottom: 1]
-    expected: FAIL
-
-  [bottom: +1]
-    expected: FAIL
-
-  [bottom: #000001]
-    expected: FAIL
-
-  [bottom: +a]
-    expected: FAIL
-
-  [bottom: +A]
-    expected: FAIL
-
-  [top: 1.5]
-    expected: FAIL
-
-  [top: +A]
-    expected: FAIL
-
-  [top: +a]
-    expected: FAIL
-
-  [top: +1]
-    expected: FAIL
-
-  [top: -1.5]
-    expected: FAIL
-
-  [top: -1\\31 .5]
-    expected: FAIL
-
-  [top: +1a]
-    expected: FAIL
-
-  [top: +1A]
-    expected: FAIL
-
-  [top: @1a]
-    expected: FAIL
-
-  [bottom: \\31 .5]
-    expected: FAIL
-
-  [top: "a"]
-    expected: FAIL
-
-  [top: #01]
-    expected: FAIL
-
-  [bottom: +1.5]
-    expected: FAIL
-
-  [bottom: -A]
-    expected: FAIL
-
-  [bottom: -a]
-    expected: FAIL
-
-  [bottom: -1\\31 ]
-    expected: FAIL
-
-  [top: #0001]
-    expected: FAIL
-
-  [bottom: -1]
-    expected: FAIL
-
-  [top: -\\31 ]
-    expected: FAIL
-
-  [top: -A]
-    expected: FAIL
-
-  [top: -a]
-    expected: FAIL
-
-  [top: -1]
-    expected: FAIL
-
-  [top: -1\\31 ]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata/url/urlencoded-parser.any.js.ini b/tests/wpt/metadata/url/urlencoded-parser.any.js.ini
index 8408c819fd66..26e57ac51548 100644
--- a/tests/wpt/metadata/url/urlencoded-parser.any.js.ini
+++ b/tests/wpt/metadata/url/urlencoded-parser.any.js.ini
@@ -11,20 +11,41 @@
   [response.formData() with input: a=b&c=d&]
     expected: FAIL
 
+  [response.formData() with input: a&b&c]
+    expected: FAIL
+
+  [request.formData() with input: _charset_=windows-1252&test=%C2x]
+    expected: FAIL
+
+  [response.formData() with input: _charset_=windows-1252&test=%C2x]
+    expected: FAIL
+
+  [response.formData() with input: &&&a=b&&&&c=d&]
+    expected: FAIL
+
+  [request.formData() with input: a=b&c=d&]
+    expected: FAIL
+
 
 [urlencoded-parser.any.worker.html]
   [request.formData() with input: a&b&c]
     expected: FAIL
 
-  [response.formData() with input: a&b&c]
+  [request.formData() with input: &&&a=b&&&&c=d&]
     expected: FAIL
 
-  [request.formData() with input: &&&a=b&&&&c=d&]
+  [request.formData() with input: a=b&c=d]
     expected: FAIL
 
-  [request.formData() with input: _charset_=windows-1252&test=%C2x]
+  [response.formData() with input: a=b&c=d&]
     expected: FAIL
 
-  [request.formData() with input: a=b&c=d]
+  [response.formData() with input: _charset_=windows-1252&test=%C2x]
+    expected: FAIL
+
+  [response.formData() with input: &&&a=b&&&&c=d&]
+    expected: FAIL
+
+  [response.formData() with input: a=b&c=d]
     expected: FAIL
 
diff --git a/tests/wpt/metadata/webaudio/the-audio-api/the-analysernode-interface/realtimeanalyser-fft-scaling.html.ini b/tests/wpt/metadata/webaudio/the-audio-api/the-analysernode-interface/realtimeanalyser-fft-scaling.html.ini
index dfc61af48f01..66bd350083b0 100644
--- a/tests/wpt/metadata/webaudio/the-audio-api/the-analysernode-interface/realtimeanalyser-fft-scaling.html.ini
+++ b/tests/wpt/metadata/webaudio/the-audio-api/the-analysernode-interface/realtimeanalyser-fft-scaling.html.ini
@@ -1,2 +1,73 @@
 [realtimeanalyser-fft-scaling.html]
-  expected: TIMEOUT
+  [X 2048-point FFT peak position is not equal to 64. Got 0.]
+    expected: FAIL
+
+  [X 128-point FFT peak position is not equal to 4. Got 0.]
+    expected: FAIL
+
+  [X 32768-point FFT peak value in dBFS is not greater than or equal to -13.56. Got -1000.]
+    expected: FAIL
+
+  [X 64-point FFT peak value in dBFS is not greater than or equal to -13.56. Got -1000.]
+    expected: FAIL
+
+  [X 4096-point FFT peak value in dBFS is not greater than or equal to -13.56. Got -1000.]
+    expected: FAIL
+
+  [< [FFT scaling tests\] 22 out of 22 assertions were failed.]
+    expected: FAIL
+
+  [X 128-point FFT peak value in dBFS is not greater than or equal to -13.56. Got -1000.]
+    expected: FAIL
+
+  [X 8192-point FFT peak position is not equal to 256. Got 0.]
+    expected: FAIL
+
+  [X 32-point FFT peak value in dBFS is not greater than or equal to -14.43. Got -1000.]
+    expected: FAIL
+
+  [X 16384-point FFT peak value in dBFS is not greater than or equal to -13.56. Got -1000.]
+    expected: FAIL
+
+  [X 256-point FFT peak value in dBFS is not greater than or equal to -13.56. Got -1000.]
+    expected: FAIL
+
+  [X 8192-point FFT peak value in dBFS is not greater than or equal to -13.56. Got -1000.]
+    expected: FAIL
+
+  [X 1024-point FFT peak position is not equal to 32. Got 0.]
+    expected: FAIL
+
+  [X 64-point FFT peak position is not equal to 2. Got 0.]
+    expected: FAIL
+
+  [X 512-point FFT peak value in dBFS is not greater than or equal to -13.56. Got -1000.]
+    expected: FAIL
+
+  [X 32-point FFT peak position is not equal to 1. Got 0.]
+    expected: FAIL
+
+  [X 16384-point FFT peak position is not equal to 512. Got 0.]
+    expected: FAIL
+
+  [X 1024-point FFT peak value in dBFS is not greater than or equal to -13.56. Got -1000.]
+    expected: FAIL
+
+  [X 2048-point FFT peak value in dBFS is not greater than or equal to -13.56. Got -1000.]
+    expected: FAIL
+
+  [X 32768-point FFT peak position is not equal to 1024. Got 0.]
+    expected: FAIL
+
+  [X 4096-point FFT peak position is not equal to 128. Got 0.]
+    expected: FAIL
+
+  [X 512-point FFT peak position is not equal to 16. Got 0.]
+    expected: FAIL
+
+  [X 256-point FFT peak position is not equal to 8. Got 0.]
+    expected: FAIL
+
+  [# AUDIT TASK RUNNER FINISHED: 1 out of 1 tasks were failed.]
+    expected: FAIL
+
diff --git a/tests/wpt/web-platform-tests/background-fetch/abort.https.window.js b/tests/wpt/web-platform-tests/background-fetch/abort.https.window.js
new file mode 100644
index 000000000000..db01bf94b85f
--- /dev/null
+++ b/tests/wpt/web-platform-tests/background-fetch/abort.https.window.js
@@ -0,0 +1,59 @@
+// META: script=/service-workers/service-worker/resources/test-helpers.sub.js
+// META: script=resources/utils.js
+'use strict';
+
+// Covers basic functionality provided by BackgroundFetchManager.abort().
+// https://wicg.github.io/background-fetch/#background-fetch-registration-abort
+
+backgroundFetchTest(async (test, backgroundFetch) => {
+  const registration = await backgroundFetch.fetch(
+      uniqueId(),
+      ['resources/feature-name.txt', '/serviceworker/resources/slow-response.php']);
+
+  assert_true(await registration.abort());
+  assert_false(await registration.abort());
+
+}, 'Aborting the same registration twice fails');
+
+backgroundFetchTest(async (test, backgroundFetch) => {
+  const registration = await backgroundFetch.fetch(
+      uniqueId(),
+      ['resources/feature-name.txt', '/serviceworker/resources/slow-response.php']);
+
+  await new Promise(resolve => {
+    let aborted = false;
+    const expectedResultText = 'Background Fetch';
+
+    registration.onprogress = async event => {
+      if (event.target.downloaded < expectedResultText.length)
+        return;
+
+      if (aborted)
+        return;
+
+      // Abort after the first file has been downloaded and check the results.
+
+      aborted = true;
+      assert_true(await registration.abort());
+
+      const {type, eventRegistration, results} = await getMessageFromServiceWorker();
+
+      assert_equals(eventRegistration.result, 'failure');
+      assert_equals(eventRegistration.failureReason, 'aborted');
+      assert_equals(registration.result, 'failure');
+      assert_equals(registration.failureReason, 'aborted');
+
+      assert_equals(type, 'backgroundfetchabort');
+
+      // The abort might have gone through before the first result was persisted.
+      if (results.length === 1) {
+        assert_true(results[0].url.includes('resources/feature-name.txt'));
+        assert_equals(results[0].status, 200);
+        assert_equals(results[0].text, expectedResultText);
+      }
+
+      resolve();
+    };
+  });
+
+}, 'Calling BackgroundFetchRegistration.abort sets the correct fields and responses are still available');
\ No newline at end of file
diff --git a/tests/wpt/web-platform-tests/background-fetch/fetch.https.window.js b/tests/wpt/web-platform-tests/background-fetch/fetch.https.window.js
index 77297186ca45..9ed7e94da3bf 100644
--- a/tests/wpt/web-platform-tests/background-fetch/fetch.https.window.js
+++ b/tests/wpt/web-platform-tests/background-fetch/fetch.https.window.js
@@ -145,6 +145,24 @@ backgroundFetchTest(async (test, backgroundFetch) => {
 
 }, 'Using Background Fetch to successfully fetch a single resource');
 
+backgroundFetchTest(async (test, backgroundFetch) => {
+  const registrationId = uniqueId();
+  const registration =
+    await backgroundFetch.fetch(registrationId, 'resources/feature-name.txt');
+
+  assert_equals(registration.result, '');
+  assert_equals(registration.failureReason, '');
+
+  const {type, eventRegistration, results} =
+    await getMessageFromServiceWorker();
+  assert_equals('backgroundfetchsuccess', type);
+
+  assert_equals(eventRegistration.id, registration.id);
+  assert_equals(registration.result, 'success');
+  assert_equals(registration.failureReason, '');
+
+}, 'Registration object gets updated values when a background fetch completes.');
+
 backgroundFetchTest(async (test, backgroundFetch) => {
   const registrationId = uniqueId();
 
@@ -240,6 +258,9 @@ backgroundFetchTest(async (test, backgroundFetch) => {
   assert_equals(eventRegistration.result, 'failure');
   assert_equals(eventRegistration.failureReason, 'bad-status');
 
+  assert_equals(registration.result, 'failure');
+  assert_equals(registration.failureReason, 'bad-status');
+
 }, 'Using Background Fetch to fetch a non-existent resource should fail.');
 
 backgroundFetchTest(async (test, backgroundFetch) => {
diff --git a/tests/wpt/web-platform-tests/background-fetch/service_workers/sw.js b/tests/wpt/web-platform-tests/background-fetch/service_workers/sw.js
index af4655dbad4e..2e3fbfff1a83 100644
--- a/tests/wpt/web-platform-tests/background-fetch/service_workers/sw.js
+++ b/tests/wpt/web-platform-tests/background-fetch/service_workers/sw.js
@@ -27,3 +27,4 @@ function handleBackgroundFetchUpdateEvent(event) {
 
 self.addEventListener('backgroundfetchsuccess', handleBackgroundFetchUpdateEvent);
 self.addEventListener('backgroundfetchfail', handleBackgroundFetchUpdateEvent);
+self.addEventListener('backgroundfetchabort', handleBackgroundFetchUpdateEvent);
diff --git a/tests/wpt/web-platform-tests/css/css-properties-values-api/registered-property-computation.html b/tests/wpt/web-platform-tests/css/css-properties-values-api/registered-property-computation.html
index 30d6b4bd609b..cbcc0bea64d4 100644
--- a/tests/wpt/web-platform-tests/css/css-properties-values-api/registered-property-computation.html
+++ b/tests/wpt/web-platform-tests/css/css-properties-values-api/registered-property-computation.html
@@ -1,117 +1,115 @@
-<!DOCTYPE HTML>
+<!DOCTYPE html>
 <link rel="help" href="https://drafts.css-houdini.org/css-properties-values-api/#calculation-of-computed-values" />
 <script src="/resources/testharness.js"></script>
 <script src="/resources/testharnessreport.js"></script>
+<script src="./resources/utils.js"></script>
 
 <style>
 #divWithFontSizeSet, #parentDiv {
     font-size: 10px;
 }
-#divWithFontSizeSet, #divWithFontSizeInherited {
-    --length-1: 12px;
-    --length-2: 13vw;
-    --length-3: 14em;
-    --length-4: 15vmin;
-    --length-5: calc(16px - 7em + 10vh);
-    --length-6: var(--length-3);
-    --length-percentage-1: 17em;
-    --length-percentage-2: 18%;
-    --length-percentage-3: calc(19em - 2%);
-    --csv-1: 10px, 3em;
-    --csv-2: 4em ,9px;
-    --csv-3: 8em;
-    --csv-4: 3% , 10vmax  , 22px;
-    --csv-5: calc(50% + 1em), 4px;
-    --csv-6: calc(13% + 37px);
-    --list-1: 10px 3em;
-    --list-2: 4em 9px;
-    --list-3: 3% 10vmax 22px;
-    --list-4: calc(50% + 1em) 4px;
-    --transform-function-1: translateX(2px);
-    --transform-function-2: translateX(10em);
-    --transform-function-3: translateX(calc(11em + 10%));
-    --transform-function-4: translateX(10%) scale(2);
-}
 </style>
 
 <div id=divWithFontSizeSet></div>
 <div id=parentDiv>
     <div id=divWithFontSizeInherited></div>
 </div>
+<div id="ref"></div>
 
 <script>
-test(() => {
-    CSS.registerProperty({name: '--length-1', syntax: '<length>', initialValue: '0px', inherits: false});
-    CSS.registerProperty({name: '--length-2', syntax: '<length>', initialValue: '0px', inherits: false});
-    CSS.registerProperty({name: '--length-3', syntax: '<length>', initialValue: '0px', inherits: false});
-    CSS.registerProperty({name: '--length-4', syntax: '<length>', initialValue: '0px', inherits: false});
-    CSS.registerProperty({name: '--length-5', syntax: '<length>', initialValue: '0px', inherits: false});
-    CSS.registerProperty({name: '--length-6', syntax: '<length>', initialValue: '0px', inherits: false});
-    CSS.registerProperty({name: '--length-percentage-1', syntax: '<length-percentage>', initialValue: '0px', inherits: false});
-    CSS.registerProperty({name: '--length-percentage-2', syntax: '<length-percentage>', initialValue: '0px', inherits: false});
-    CSS.registerProperty({name: '--length-percentage-3', syntax: '<length-percentage>', initialValue: '0px', inherits: false});
-    CSS.registerProperty({name: '--csv-1', syntax: '<length>#', initialValue: '0px', inherits: false});
-    CSS.registerProperty({name: '--csv-2', syntax: '<length>#', initialValue: '0px', inherits: false});
-    CSS.registerProperty({name: '--csv-3', syntax: '<length>#', initialValue: '0px', inherits: false});
-    CSS.registerProperty({name: '--csv-4', syntax: '<length-percentage>#', initialValue: '0px', inherits: false});
-    CSS.registerProperty({name: '--csv-5', syntax: '<length-percentage>#', initialValue: '0px', inherits: false});
-    CSS.registerProperty({name: '--csv-6', syntax: '<length-percentage>#', initialValue: '0px', inherits: false});
-    CSS.registerProperty({name: '--list-1', syntax: '<length>+', initialValue: '0px', inherits: false});
-    CSS.registerProperty({name: '--list-2', syntax: '<length>+', initialValue: '0px', inherits: false});
-    CSS.registerProperty({name: '--list-3', syntax: '<length-percentage>+', initialValue: '0px', inherits: false});
-    CSS.registerProperty({name: '--list-4', syntax: '<length-percentage>+', initialValue: '0px', inherits: false});
-    CSS.registerProperty({name: '--transform-function-1', syntax: '<transform-function>', initialValue: 'translateX(0px)', inherits: false});
-    CSS.registerProperty({name: '--transform-function-2', syntax: '<transform-function>', initialValue: 'translateX(0px)', inherits: false});
-    CSS.registerProperty({name: '--transform-function-3', syntax: '<transform-function>', initialValue: 'translateX(0px)', inherits: false});
-    CSS.registerProperty({name: '--transform-function-4', syntax: '<transform-function>+', initialValue: 'translateX(0px)', inherits: false});
-}, "CSS.registerProperty");
-
-for (var element of [divWithFontSizeSet, divWithFontSizeInherited]) {
-    var id = element.id;
-    var computedStyle = getComputedStyle(element);
+
+for (let element of [divWithFontSizeSet, divWithFontSizeInherited]) {
+    let id = element.id;
+
+    // Generate a property and temporarily set its value. Then call 'fn' with
+    // the name of the generated property.
+    function with_custom_property(reg, value, fn) {
+        let name = generate_property(reg);
+
+        // Because we want to include the parsing step, insert a stylesheet
+        // node with textContent.
+        let node = document.createElement('style');
+        node.textContent = `#${id} { ${name}: ${value}; }`;
+        document.body.append(node);
+
+        try {
+            fn(name);
+        } finally {
+            node.remove();
+        }
+    }
+
+    function assert_computed_value(syntax, value, expected) {
+        with_custom_property(syntax, value, (name) => {
+            let actual = getComputedStyle(element).getPropertyValue(name);
+            assert_equals(actual, expected);
+        });
+    }
+
+    // Computes an absolute reference value for some length.
+    //
+    // E.g. to figure out how many pixels '10vh' is, do length_ref('10vh').
+    function length_ref(value, refnode = ref) {
+        try {
+            // The reference property 'min-height' is chosen arbitrarily, but
+            // avoid properties with "resolved value is used value"-behavior
+            // [1], as it may affect rounding, and custom properties do not
+            // have this behavior.
+            //
+            // [1] https://drafts.csswg.org/cssom/#resolved-values
+            const ref_property = 'min-height';
+            refnode.style = `${ref_property}: ${value}`;
+            return getComputedStyle(refnode).getPropertyValue(ref_property);
+        } finally {
+            refnode.style = '';
+        }
+    }
 
     test(function() {
-        assert_equals(computedStyle.getPropertyValue('--length-1'), '12px');
-        assert_equals(computedStyle.getPropertyValue('--length-2'), '104px');
-        assert_equals(computedStyle.getPropertyValue('--length-3'), '140px');
-        assert_equals(computedStyle.getPropertyValue('--length-4'), '90px');
-        assert_equals(computedStyle.getPropertyValue('--length-5'), '6px');
-        assert_equals(computedStyle.getPropertyValue('--length-6'), '140px');
+        assert_computed_value('<length>', '12px', '12px');
+        assert_computed_value('<length>', '13vw', length_ref('13vw'));
+        assert_computed_value('<length>', '14em', '140px');
+        assert_computed_value('<length>', '15vmin', length_ref('15vmin'));
+        assert_computed_value('<length>', 'calc(16px - 7em + 10vh)', length_ref('calc(10vh - 54px)'));
+        with_custom_property('<length>', '14em', (name) => {
+            assert_computed_value('<length>', `var(${name})`, '140px');
+        });
     }, "<length> values are computed correctly for " + id);
 
     test(function() {
-        assert_equals(computedStyle.getPropertyValue('--length-percentage-1'), '170px');
-        assert_equals(computedStyle.getPropertyValue('--length-percentage-2'), '18%');
-        assert_equals(computedStyle.getPropertyValue('--length-percentage-3'), 'calc(190px + -2%)');
+        assert_computed_value('<length-percentage>', '17em', '170px');
+        assert_computed_value('<length-percentage>', '18%', '18%');
+        assert_computed_value('<length-percentage>', 'calc(19em - 2%)', 'calc(190px + -2%)');
     }, "<length-percentage> values are computed correctly for " + id);
 
     test(function() {
-        assert_equals(computedStyle.getPropertyValue('--csv-1'), '10px, 30px');
-        assert_equals(computedStyle.getPropertyValue('--csv-2'), '40px, 9px');
-        assert_equals(computedStyle.getPropertyValue('--csv-3'), '80px');
+        assert_computed_value('<length>#', '10px, 3em', '10px, 30px');
+        assert_computed_value('<length>#', '10px, 3em', '10px, 30px');
+        assert_computed_value('<length>#', '4em ,9px', '40px, 9px');
+        assert_computed_value('<length>#', '8em', '80px');
     }, "<length># values are computed correctly for " + id);
 
     test(function() {
-        assert_equals(computedStyle.getPropertyValue('--csv-4'), '3%, 80px, 22px');
-        assert_equals(computedStyle.getPropertyValue('--csv-5'), 'calc(10px + 50%), 4px');
-        assert_equals(computedStyle.getPropertyValue('--csv-6'), 'calc(37px + 13%)');
+        assert_computed_value('<length-percentage>#', '3% , 10vmax  , 22px', ['3%', length_ref('10vmax'), '22px'].join(', '));
+        assert_computed_value('<length-percentage>#', 'calc(50% + 1em), 4px', 'calc(10px + 50%), 4px');
+        assert_computed_value('<length-percentage>#', 'calc(13% + 37px)', 'calc(37px + 13%)');
     }, "<length-percentage># values are computed correctly for " + id);
 
     test(function() {
-        assert_equals(computedStyle.getPropertyValue('--list-1'), '10px 30px');
-        assert_equals(computedStyle.getPropertyValue('--list-2'), '40px 9px');
+        assert_computed_value('<length>+', '10px 3em', '10px 30px');
+        assert_computed_value('<length>+', '4em 9px', '40px 9px');
     }, "<length>+ values are computed correctly for " + id);
 
     test(function() {
-        assert_equals(computedStyle.getPropertyValue('--list-3'), '3% 80px 22px');
-        assert_equals(computedStyle.getPropertyValue('--list-4'), 'calc(10px + 50%) 4px');
+        assert_computed_value('<length-percentage>+', '3% 10vmax 22px', ['3%', length_ref('10vmax'), '22px'].join(' '));
+        assert_computed_value('<length-percentage>+', 'calc(50% + 1em) 4px', 'calc(10px + 50%) 4px');
     }, "<length-percentage>+ values are computed correctly for " + id);
 
     test(function() {
-        assert_equals(computedStyle.getPropertyValue('--transform-function-1'), 'translateX(2px)');
-        assert_equals(computedStyle.getPropertyValue('--transform-function-2'), 'translateX(100px)');
-        assert_equals(computedStyle.getPropertyValue('--transform-function-3'), 'translateX(calc(110px + 10%))');
-        assert_equals(computedStyle.getPropertyValue('--transform-function-4'), 'translateX(10%) scale(2)');
+        assert_computed_value('<transform-function>', 'translateX(2px)', 'translateX(2px)');
+        assert_computed_value('<transform-function>', 'translateX(10em)', 'translateX(100px)');
+        assert_computed_value('<transform-function>', 'translateX(calc(11em + 10%))', 'translateX(calc(110px + 10%))');
+        assert_computed_value('<transform-function>+', 'translateX(10%) scale(2)', 'translateX(10%) scale(2)');
     }, "<transform-function> values are computed correctly for " + id);
 }
 </script>
diff --git a/tests/wpt/web-platform-tests/css/css-properties-values-api/resources/utils.js b/tests/wpt/web-platform-tests/css/css-properties-values-api/resources/utils.js
new file mode 100644
index 000000000000..c4dc3fd5a8d9
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-properties-values-api/resources/utils.js
@@ -0,0 +1,86 @@
+let next_property_id = 1;
+
+// Generate a unique property name on the form --prop-N.
+function generate_name() {
+  return `--prop-${next_property_id++}`;
+}
+
+// Produce a compatible initial value for the specified syntax.
+function any_initial_value(syntax) {
+  let components = syntax.split('|').map(x => x.trim())
+  let first_component = components[0];
+
+  if (first_component.endsWith('+') || first_component.endsWith('#'))
+    first_component = first_component.slice(0, -1);
+
+  switch (first_component) {
+    case '*':
+    case '<custom-ident>':
+      return 'NULL';
+    case '<angle>':
+      return '0deg';
+    case '<color>':
+      return 'rgb(0, 0, 0)';
+    case '<image>':
+    case '<url>':
+      return 'url(0)';
+    case '<integer>':
+    case '<length-percentage>':
+    case '<length>':
+    case '<number>':
+      return '0';
+    case '<percentage>':
+      return '0%';
+    case '<resolution>':
+      return '0dpi';
+    case '<time>':
+      return '0s';
+    case '<transform-function>':
+    case '<transform-list>':
+      return 'matrix(0, 0, 0, 0, 0, 0)';
+    default:
+      // We assume syntax is a specific custom ident.
+      return first_component;
+  }
+}
+
+// Registers a unique property on the form '--prop-N' and returns the name.
+// Any value except 'syntax' may be omitted, in which case the property will
+// not inherit, and some undefined (but compatible) initial value will be
+// generated. If a single string is used as the argument, it is assumed to be
+// the syntax.
+function generate_property(reg) {
+  let syntax = typeof(reg) === 'string' ? reg : reg.syntax;
+  let initial = typeof(reg.initialValue) === 'undefined' ? any_initial_value(syntax)
+                                                         : reg.initialValue;
+  let inherits = typeof(reg.inherits) === 'undefined' ? false : reg.inherits;
+
+  let name = generate_name();
+  CSS.registerProperty({
+    name: name,
+    syntax: syntax,
+    initialValue: initial,
+    inherits: inherits
+  });
+  return name;
+}
+
+function all_syntaxes() {
+  return [
+    '*',
+    '<angle>',
+    '<color>',
+    '<custom-ident>',
+    '<image>',
+    '<integer>',
+    '<length-percentage>',
+    '<length>',
+    '<number>',
+    '<percentage>',
+    '<resolution>',
+    '<time>',
+    '<transform-function>',
+    '<transform-list>',
+    '<url>'
+  ]
+}
diff --git a/tests/wpt/web-platform-tests/css/css-properties-values-api/self-utils.html b/tests/wpt/web-platform-tests/css/css-properties-values-api/self-utils.html
new file mode 100644
index 000000000000..530c5f677ad2
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-properties-values-api/self-utils.html
@@ -0,0 +1,35 @@
+<!DOCTYPE html>
+<title>Self-test for utils.js</title>
+<link rel="help" href="https://drafts.css-houdini.org/css-properties-values-api-1/">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="./resources/utils.js"></script>
+<div id=outer><div id=inner></div></div>
+<script>
+
+test(function(){
+  let syntaxes = all_syntaxes().concat([
+    'foo',
+    'bar | <length>',
+    '<angle> | <length>'
+  ]);
+  // Don't throw:
+  syntaxes.forEach(generate_property);
+}, 'Default initial values of generated properties are valid (self-test).');
+
+test(function(){
+  try {
+    let inherited = generate_property({ syntax: '<length>', inherits: true });
+    let non_inherited = generate_property({ syntax: '<length>', inherits: false, initialValue: '5px' });
+    outer.style = `${inherited}: 10px; ${non_inherited}: 11px;`;
+    assert_equals(getComputedStyle(outer).getPropertyValue(inherited), '10px');
+    assert_equals(getComputedStyle(outer).getPropertyValue(non_inherited), '11px');
+    assert_equals(getComputedStyle(inner).getPropertyValue(inherited), '10px');
+    assert_equals(getComputedStyle(inner).getPropertyValue(non_inherited), '5px');
+  } finally {
+    outer.style = '';
+    inner.style = '';
+  }
+}, 'Generated properties respect inherits flag');
+
+</script>
diff --git a/tests/wpt/web-platform-tests/docs/_running-tests/safari.md b/tests/wpt/web-platform-tests/docs/_running-tests/safari.md
index e6cedd97f965..3ef508d3780a 100644
--- a/tests/wpt/web-platform-tests/docs/_running-tests/safari.md
+++ b/tests/wpt/web-platform-tests/docs/_running-tests/safari.md
@@ -22,7 +22,7 @@ Now, run the tests using the `safari` product:
 ```
 
 This will use the `safaridriver` found on the path, which will be stable Safari.
-To run Safari Technology Preview instead, use the `--webdriver-binary` argument:
+To run Safari Technology Preview instead, use the `--channel=preview` argument:
 ```
-./wpt run --webdriver-binary "/Applications/Safari Technology Preview.app/Contents/MacOS/safaridriver" safari [test_list]
+./wpt run --channel=preview safari [test_list]
 ```
diff --git a/tests/wpt/web-platform-tests/fetch/api/abort/serviceworker-intercepted.https.html b/tests/wpt/web-platform-tests/fetch/api/abort/serviceworker-intercepted.https.html
index 623036d46639..a88aa896c90b 100644
--- a/tests/wpt/web-platform-tests/fetch/api/abort/serviceworker-intercepted.https.html
+++ b/tests/wpt/web-platform-tests/fetch/api/abort/serviceworker-intercepted.https.html
@@ -21,7 +21,8 @@
   }
 
   promise_test(async t => {
-    const scope = SCOPE + "?q=aborted-not-intercepted";
+    const suffix = "?q=aborted-not-intercepted";
+    const scope = SCOPE + suffix;
     await setupRegistration(t, scope);
     const iframe = await with_iframe(scope);
     add_completion_callback(_ => iframe.remove());
@@ -33,8 +34,13 @@
 
     const nextData = new Promise(resolve => {
       w.navigator.serviceWorker.addEventListener('message', function once(event) {
-        w.navigator.serviceWorker.removeEventListener('message', once);
-        resolve(event.data);
+        // The message triggered by the iframe's document's fetch
+        // request cannot get dispatched by the time we add the event
+        // listener, so we have to guard against it.
+        if (!event.data.endsWith(suffix)) {
+          w.navigator.serviceWorker.removeEventListener('message', once);
+          resolve(event.data);
+        }
       })
     });
 
diff --git a/tests/wpt/web-platform-tests/fetch/api/request/destination/resources/fetch-destination-worker-no-load-event.js b/tests/wpt/web-platform-tests/fetch/api/request/destination/resources/fetch-destination-worker-no-load-event.js
index 5a3c679cc03e..c1b6c506e957 100644
--- a/tests/wpt/web-platform-tests/fetch/api/request/destination/resources/fetch-destination-worker-no-load-event.js
+++ b/tests/wpt/web-platform-tests/fetch/api/request/destination/resources/fetch-destination-worker-no-load-event.js
@@ -1,7 +1,8 @@
 self.addEventListener('fetch', function(event) {
-    if (event.request.url.includes('dummy')) {
+    const url = event.request.url;
+    if (url.includes('dummy') && url.includes('?')) {
         event.waitUntil(async function() {
-            let destination = new URL(event.request.url).searchParams.get("dest");
+            let destination = new URL(url).searchParams.get("dest");
             var result = "FAIL";
             if (event.request.destination == destination) {
               result = "PASS";
diff --git a/tests/wpt/web-platform-tests/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-tokenization-noopener.html b/tests/wpt/web-platform-tests/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-tokenization-noopener.html
index cac23648ade4..c31e75fdf57e 100644
--- a/tests/wpt/web-platform-tests/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-tokenization-noopener.html
+++ b/tests/wpt/web-platform-tests/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-tokenization-noopener.html
@@ -40,8 +40,10 @@
     'noOpenER',
     '  NOopener',
     '=NOOPENER',
-    'noopener=NOOPENER', // => ('noopener', 'noopener')
-    'NOOPENER=noopener' // => ('noopener', 'noopener')
+    'noopener=1',
+    'NOOPENER=1',
+    'NOOPENER=yes',
+    'noopener=YES',
   ];
   featureVariants.forEach(feature => {
     var win = window.open(windowURL, '', feature);
@@ -82,9 +84,9 @@
     'noopener==,',
     'noopener=\n ,',
     'noopener = \t ,',
-    'noopener\n=\r noopener,', // => ('noopener', 'noopener')
+    'noopener\n=\r 1,', // => ('noopener', '1')
     'noopener=,yes', // => ('noopener'), ('yes')
-    'noopener= foo=,', // => ('noopener', 'foo')
+    'noopener= yes=,', // => ('noopener', 'yes')
     'noopener = \u000Cyes' // => ('noopener', 'yes')
   ];
   featureVariants.forEach(feature => {
@@ -96,14 +98,14 @@
 test (t => {
   // Tokenizing `value` should collect any non-separator code points until first separator
   var featureVariants = [
-    'noopener=noopener', // => ('noopener', 'noopener')
+    'noopener=1', // => ('noopener', 'noopener')
     'noopener=yes', // => ('noopener', 'yes')
     'noopener = yes ,', // => ('noopener', 'yes')
     'noopener=\nyes  ,', // => ('noopener', 'yes')
     'noopener=yes yes', // => ('noopener', 'yes'), ('yes', '')
     'noopener=yes\ts', // => ('noopener', 'yes'), ('s', '')
     'noopener==', // => ('noopener', '')
-    'noopener=0\n,', // => ('noopener', '0')
+    'noopener=1\n,', // => ('noopener', '1')
     '==noopener===', // => ('noopener', '')
     'noopener==\u000C' // => ('noopener', '')
   ];
@@ -114,20 +116,30 @@
 }, 'Tokenizing should read characters until first window feature separator as `value`');
 
 test (t => {
-  // If tokenizedFeatures contains an entry with the key "noopener"...disown opener
-  // i.e. `value` should be irrelevant
   var featureVariants = [
-    'noopener=false',
-    ',noopener=0, ',
-    'foo=bar,noopener=noopener,',
-    'noopener=true',
-    'noopener=foo\nbar\t'
+    'noopener=1',
+    'noopener=2',
+    'noopener=12345',
+    'noopener=1.5',
+    'noopener=-1',
   ];
   featureVariants.forEach(feature => {
     var win = window.open(windowURL, '', feature);
     assert_equals(win, null, `"${feature}" should activate feature "noopener"`);
   });
-}, '"noopener" should be based on name (key), not value');
+}, 'Integer values other than 0 should activate the feature');
+
+test (t => {
+  var featureVariants = [
+    'noopener=0',
+    'noopener=0.5',
+    'noopener=error',
+  ];
+  featureVariants.forEach(feature => {
+    var win = window.open(windowURL, '', feature);
+    assert_not_equals(win, null, `"${feature}" should NOT activate feature "noopener"`);
+  });
+}, 'Integer value of 0 should not activate the feature');
 
 test (t => {
   var invalidFeatureVariants = [
diff --git a/tests/wpt/web-platform-tests/interfaces/web-animations.idl b/tests/wpt/web-platform-tests/interfaces/web-animations.idl
index 7dce1002e666..9a3579da75f2 100644
--- a/tests/wpt/web-platform-tests/interfaces/web-animations.idl
+++ b/tests/wpt/web-platform-tests/interfaces/web-animations.idl
@@ -1,7 +1,7 @@
 // GENERATED CONTENT - DO NOT EDIT
 // Content was automatically extracted by Reffy into reffy-reports
 // (https://github.com/tidoust/reffy-reports)
-// Source: Web Animations (https://w3c.github.io/web-animations/)
+// Source: Web Animations (https://drafts.csswg.org/web-animations-1/)
 
 [Exposed=Window]
 interface AnimationTimeline {
diff --git a/tests/wpt/web-platform-tests/interfaces/web-share.idl b/tests/wpt/web-platform-tests/interfaces/web-share.idl
index 36ffa43e3797..7fa83b0fed51 100644
--- a/tests/wpt/web-platform-tests/interfaces/web-share.idl
+++ b/tests/wpt/web-platform-tests/interfaces/web-share.idl
@@ -1,7 +1,7 @@
 // GENERATED CONTENT - DO NOT EDIT
 // Content was automatically extracted by Reffy into reffy-reports
 // (https://github.com/tidoust/reffy-reports)
-// Source: Web Share API (https://wicg.github.io/web-share/)
+// Source: Web Share API - Level 1 (https://wicg.github.io/web-share/)
 
 partial interface Navigator {
   [SecureContext] Promise<void> share(optional ShareData data);
diff --git a/tests/wpt/web-platform-tests/picture-in-picture/resources/picture-in-picture-helpers.js b/tests/wpt/web-platform-tests/picture-in-picture/resources/picture-in-picture-helpers.js
index 96972dcbc8ef..7561944a18d0 100644
--- a/tests/wpt/web-platform-tests/picture-in-picture/resources/picture-in-picture-helpers.js
+++ b/tests/wpt/web-platform-tests/picture-in-picture/resources/picture-in-picture-helpers.js
@@ -1,9 +1,3 @@
-if (!('pictureInPictureEnabled' in document)) {
-  HTMLVideoElement.prototype.requestPictureInPicture = function() {
-    return Promise.reject('Picture-in-Picture API is not available');
-  }
-}
-
 function loadVideo(activeDocument, sourceUrl) {
   return new Promise((resolve, reject) => {
     const document = activeDocument || window.document;
diff --git a/tests/wpt/web-platform-tests/resource-timing/resource_timing_buffer_full_eventually.html b/tests/wpt/web-platform-tests/resource-timing/resource_timing_buffer_full_eventually.html
index 7ca8237b02cc..ce745237c065 100644
--- a/tests/wpt/web-platform-tests/resource-timing/resource_timing_buffer_full_eventually.html
+++ b/tests/wpt/web-platform-tests/resource-timing/resource_timing_buffer_full_eventually.html
@@ -16,15 +16,23 @@
         function() {
             // Scripts appended in JS to ensure setResourceTimingBufferSize is called before.
             let counter = performance.getEntriesByType("resource").length;
-            function appendScript() {
-                const src = "resources/empty.js?" + counter;
-                const script = document.createElement('script');
-                script.type = 'text/javascript';
-                script.onload = function() { ++counter; appendScript()};
-                script.src = src;
-                document.body.appendChild(script);
+            function appendScripts() {
+                const documentFragment = document.createDocumentFragment();
+                // Add 100 elements at a time to avoid page reflow every time.
+                let numScriptsAccumulated = 0;
+                while (numScriptsAccumulated < 100) {
+                    const src = "resources/empty.js?" + counter;
+                    const script = document.createElement('script');
+                    script.type = 'text/javascript';
+                    script.src = src;
+                    documentFragment.appendChild(script);
+                    ++counter;
+                    ++numScriptsAccumulated;
+                }
+                document.body.appendChild(documentFragment);
+                t.step_timeout(appendScripts, 20);
             }
-            appendScript();
+            appendScripts();
         });
 </script>
 </body>
diff --git a/tests/wpt/web-platform-tests/service-workers/service-worker/postmessage-to-client.https.html b/tests/wpt/web-platform-tests/service-workers/service-worker/postmessage-to-client.https.html
index 15d2e8893370..b1dc41a018f2 100644
--- a/tests/wpt/web-platform-tests/service-workers/service-worker/postmessage-to-client.https.html
+++ b/tests/wpt/web-platform-tests/service-workers/service-worker/postmessage-to-client.https.html
@@ -51,4 +51,208 @@
         })
       .then(e => { assert_equals(e.data, 'quit'); });
   }, 'postMessage from ServiceWorker to Client.');
+
+// This function creates a message listener that captures all messages
+// sent to this window and matches them with corresponding requests.
+// This frees test code from having to use clunky constructs just to
+// avoid race conditions, since the relative order of message and
+// request arrival doesn't matter.
+function create_message_listener(t) {
+    const listener = {
+        messages: new Set(),
+        requests: new Set(),
+        waitFor: function(predicate) {
+            for (const event of this.messages) {
+                // If a message satisfying the predicate has already
+                // arrived, it gets matched to this request.
+                if (predicate(event)) {
+                    this.messages.delete(event);
+                    return Promise.resolve(event);
+                }
+            }
+
+            // If no match was found, the request is stored and a
+            // promise is returned.
+            const request = { predicate };
+            const promise = new Promise(resolve => request.resolve = resolve);
+            this.requests.add(request);
+            return promise;
+        }
+    };
+    window.onmessage = t.step_func(event => {
+        for (const request of listener.requests) {
+            // If the new message matches a stored request's
+            // predicate, the request's promise is resolved with this
+            // message.
+            if (request.predicate(event)) {
+                listener.requests.delete(request);
+                request.resolve(event);
+                return;
+            }
+        };
+
+        // No outstanding request for this message, store it in case
+        // it's requested later.
+        listener.messages.add(event);
+    });
+    return listener;
+}
+
+async function service_worker_register_and_activate(t, script, scope) {
+    const registration = await service_worker_unregister_and_register(t, script, scope);
+    t.add_cleanup(() => registration.unregister());
+    const worker = registration.installing;
+    await wait_for_state(t, worker, 'activated');
+    return worker;
+}
+
+// Add an iframe (parent) whose document contains a nested iframe
+// (child), then set the child's src attribute to child_url and return
+// its Window (without waiting for it to finish loading).
+async function with_nested_iframes(t, child_url) {
+    const parent = await with_iframe('resources/nested-iframe-parent.html?role=parent');
+    t.add_cleanup(() => parent.remove());
+    const child = parent.contentWindow.document.getElementById('child');
+    child.setAttribute('src', child_url);
+    return child.contentWindow;
+}
+
+// Returns a predicate matching a fetch message with the specified
+// key.
+function fetch_message(key) {
+    return event => event.data.type === 'fetch' && event.data.key === key;
+}
+
+// Returns a predicate matching a ping message with the specified
+// payload.
+function ping_message(data) {
+    return event => event.data.type === 'ping' && event.data.data === data;
+}
+
+// A client message queue test is a testharness.js test with some
+// additional setup:
+// 1. A listener (see create_message_listener)
+// 2. An active service worker
+// 3. Two nested iframes
+// 4. A state transition function that controls the order of events
+//    during the test
+function client_message_queue_test(url, test_function, description) {
+    promise_test(async t => {
+        t.listener = create_message_listener(t);
+
+        const script = 'resources/stalling-service-worker.js';
+        const scope = 'resources/';
+        t.service_worker = await service_worker_register_and_activate(t, script, scope);
+
+        // We create two nested iframes such that both are controlled by
+        // the newly installed service worker.
+        const child_url = url + '?role=child';
+        t.frame = await with_nested_iframes(t, child_url);
+
+        t.state_transition = async function(from, to, scripts) {
+            // A state transition begins with the child's parser
+            // fetching a script due to a <script> tag. The request
+            // arrives at the service worker, which notifies the
+            // parent, which in turn notifies the test. Note that the
+            // event loop keeps spinning while the parser is waiting.
+            const request = await this.listener.waitFor(fetch_message(to));
+
+            // The test instructs the service worker to send two ping
+            // messages through the Client interface: first to the
+            // child, then to the parent.
+            this.service_worker.postMessage(from);
+
+            // When the parent receives the ping message, it forwards
+            // it to the test. Assuming that messages to both child
+            // and parent are mapped to the same task queue (this is
+            // not [yet] required by the spec), receiving this message
+            // guarantees that the child has already dispatched its
+            // message if it was allowed to do so.
+            await this.listener.waitFor(ping_message(from));
+
+            // Finally, reply to the service worker's fetch
+            // notification with the script it should use as the fetch
+            // request's response. This is a defensive mechanism that
+            // ensures the child's parser really is blocked until the
+            // test is ready to continue.
+            request.ports[0].postMessage([`state = '${to}';`].concat(scripts));
+        };
+
+        await test_function(t);
+    }, description);
+}
+
+function client_message_queue_enable_test(
+    install_script,
+    start_script,
+    earliest_dispatch,
+    description)
+{
+    function later_state(state1, state2) {
+        const states = ['init', 'install', 'start', 'finish', 'loaded'];
+        const index1 = states.indexOf(state1);
+        const index2 = states.indexOf(state2);
+        const max_index = Math.max(index1, index2);
+        return states[max_index];
+    }
+
+    client_message_queue_test('enable-client-message-queue.html', async t => {
+        // While parsing the child's document, the child transitions
+        // from the 'init' state all the way to the 'finish' state.
+        // Once parsing is finished it would enter the final 'loaded'
+        // state. All but the last transition require assitance from
+        // the test.
+        await t.state_transition('init', 'install', [install_script]);
+        await t.state_transition('install', 'start', [start_script]);
+        await t.state_transition('start', 'finish', []);
+
+        // Wait for all messages to get dispatched on the child's
+        // ServiceWorkerContainer and then verify that each message
+        // was dispatched while the child was in the correct state.
+        const report = await t.frame.report;
+        ['init', 'install', 'start'].forEach(state => {
+            const dispatch = later_state(state, earliest_dispatch);
+            assert_equals(report[state], dispatch,
+                          `Message sent in state '${state}' dispatched in state '${dispatch}'`);
+        });
+    }, description);
+}
+
+const empty_script = ``;
+
+const add_event_listener =
+    `navigator.serviceWorker.addEventListener('message', handle_message);`;
+
+const set_onmessage = `navigator.serviceWorker.onmessage = handle_message;`;
+
+const start_messages = `navigator.serviceWorker.startMessages();`;
+
+client_message_queue_enable_test(add_event_listener, empty_script, 'loaded',
+    'Messages from ServiceWorker to Client only received after DOMContentLoaded event.');
+
+client_message_queue_enable_test(add_event_listener, start_messages, 'start',
+    'Messages from ServiceWorker to Client only received after calling startMessages().');
+
+client_message_queue_enable_test(set_onmessage, empty_script, 'install',
+    'Messages from ServiceWorker to Client only received after setting onmessage.');
+
+const resolve_manual_promise = `resolve_manual_promise();`
+
+async function test_microtasks_when_client_message_queue_enabled(t, scripts) {
+    await t.state_transition('init', 'start', scripts.concat([resolve_manual_promise]));
+    let result = await t.frame.result;
+    assert_equals(result[0], 'microtask', 'The microtask was executed first.');
+    assert_equals(result[1], 'message', 'The message was dispatched.');
+}
+
+client_message_queue_test('message-vs-microtask.html', t => {
+    return test_microtasks_when_client_message_queue_enabled(t, [
+        add_event_listener,
+        start_messages,
+    ]);
+}, 'Microtasks run before dispatching messages after calling startMessages().');
+
+client_message_queue_test('message-vs-microtask.html', t => {
+    return test_microtasks_when_client_message_queue_enabled(t, [set_onmessage]);
+}, 'Microtasks run before dispatching messages after setting onmessage.');
 </script>
diff --git a/tests/wpt/web-platform-tests/service-workers/service-worker/resources/about-blank-replacement-ping-frame.py b/tests/wpt/web-platform-tests/service-workers/service-worker/resources/about-blank-replacement-ping-frame.py
index 58fb4403f9c6..bb07c241ad49 100644
--- a/tests/wpt/web-platform-tests/service-workers/service-worker/resources/about-blank-replacement-ping-frame.py
+++ b/tests/wpt/web-platform-tests/service-workers/service-worker/resources/about-blank-replacement-ping-frame.py
@@ -41,6 +41,7 @@ def main(request, response):
       });
     }
   });
+  win.navigator.serviceWorker.startMessages();
 }
 </script>
 </body>
diff --git a/tests/wpt/web-platform-tests/service-workers/service-worker/resources/enable-client-message-queue.html b/tests/wpt/web-platform-tests/service-workers/service-worker/resources/enable-client-message-queue.html
new file mode 100644
index 000000000000..512bd14bc67d
--- /dev/null
+++ b/tests/wpt/web-platform-tests/service-workers/service-worker/resources/enable-client-message-queue.html
@@ -0,0 +1,39 @@
+<!DOCTYPE html>
+<script>
+  // The state variable is used by handle_message to record the time
+  // at which a message was handled. It's updated by the scripts
+  // loaded by the <script> tags at the bottom of the file as well as
+  // by the event listener added here.
+  var state = 'init';
+  addEventListener('DOMContentLoaded', () => state = 'loaded');
+
+  // We expect to get three ping messages from the service worker.
+  const expected = ['init', 'install', 'start'];
+  let promises = {};
+  let resolvers = {};
+  expected.forEach(name => {
+    promises[name] = new Promise(resolve => resolvers[name] = resolve);
+  });
+
+  // Once all messages have been dispatched, the state in which each
+  // of them was dispatched is recorded in the draft. At that point
+  // the draft becomes the final report.
+  var draft = {};
+  var report = Promise.all(Object.values(promises)).then(() => window.draft);
+
+  // This message handler is installed by the 'install' script.
+  function handle_message(event) {
+    const data = event.data.data;
+    draft[data] = state;
+    resolvers[data]();
+  }
+</script>
+
+<!--
+  The controlling service worker will delay the response to these
+  fetch requests until the test instructs it how to reply. Note that
+  the event loop keeps spinning while the parser is blocked.
+-->
+<script src="empty.js?key=install"></script>
+<script src="empty.js?key=start"></script>
+<script src="empty.js?key=finish"></script>
diff --git a/tests/wpt/web-platform-tests/service-workers/service-worker/resources/message-vs-microtask.html b/tests/wpt/web-platform-tests/service-workers/service-worker/resources/message-vs-microtask.html
new file mode 100644
index 000000000000..2c45c59a475a
--- /dev/null
+++ b/tests/wpt/web-platform-tests/service-workers/service-worker/resources/message-vs-microtask.html
@@ -0,0 +1,18 @@
+<!DOCTYPE html>
+<script>
+  let draft = [];
+  var resolve_manual_promise;
+  let manual_promise =
+    new Promise(resolve => resolve_manual_promise = resolve).then(() => draft.push('microtask'));
+
+  let resolve_message_promise;
+  let message_promise = new Promise(resolve => resolve_message_promise = resolve);
+  function handle_message(event) {
+    draft.push('message');
+    resolve_message_promise();
+  }
+
+  var result = Promise.all([manual_promise, message_promise]).then(() => draft);
+</script>
+
+<script src="empty.js?key=start"></script>
diff --git a/tests/wpt/web-platform-tests/service-workers/service-worker/resources/nested-iframe-parent.html b/tests/wpt/web-platform-tests/service-workers/service-worker/resources/nested-iframe-parent.html
new file mode 100644
index 000000000000..115ab26e1221
--- /dev/null
+++ b/tests/wpt/web-platform-tests/service-workers/service-worker/resources/nested-iframe-parent.html
@@ -0,0 +1,5 @@
+<!DOCTYPE html>
+<script>
+  navigator.serviceWorker.onmessage = event => parent.postMessage(event.data, '*', event.ports);
+</script>
+<iframe id='child'></iframe>
diff --git a/tests/wpt/web-platform-tests/service-workers/service-worker/resources/stalling-service-worker.js b/tests/wpt/web-platform-tests/service-workers/service-worker/resources/stalling-service-worker.js
new file mode 100644
index 000000000000..fdf1e6cac04e
--- /dev/null
+++ b/tests/wpt/web-platform-tests/service-workers/service-worker/resources/stalling-service-worker.js
@@ -0,0 +1,54 @@
+async function post_message_to_client(role, message, ports) {
+    (await clients.matchAll()).forEach(client => {
+        if (new URL(client.url).searchParams.get('role') === role) {
+            client.postMessage(message, ports);
+        }
+    });
+}
+
+async function post_message_to_child(message, ports) {
+    await post_message_to_client('child', message, ports);
+}
+
+function ping_message(data) {
+    return { type: 'ping', data };
+}
+
+self.onmessage = event => {
+    const message = ping_message(event.data);
+    post_message_to_child(message);
+    post_message_to_parent(message);
+}
+
+async function post_message_to_parent(message, ports) {
+    await post_message_to_client('parent', message, ports);
+}
+
+function fetch_message(key) {
+    return { type: 'fetch', key };
+}
+
+// Send a message to the parent along with a MessagePort to respond
+// with.
+function report_fetch_request(key) {
+    const channel = new MessageChannel();
+    const reply = new Promise(resolve => {
+        channel.port1.onmessage = resolve;
+    }).then(event => event.data);
+    return post_message_to_parent(fetch_message(key), [channel.port2]).then(() => reply);
+}
+
+function respond_with_script(script) {
+    return new Response(new Blob(script, { type: 'text/javascript' }));
+}
+
+// Whenever a controlled document requests a URL with a 'key' search
+// parameter we report the request to the parent frame and wait for
+// a response. The content of the response is then used to respond to
+// the fetch request.
+addEventListener('fetch', event => {
+    let key = new URL(event.request.url).searchParams.get('key');
+    if (key) {
+        event.respondWith(report_fetch_request(key).then(respond_with_script));
+    }
+});
diff --git a/tests/wpt/web-platform-tests/tools/wpt/browser.py b/tests/wpt/web-platform-tests/tools/wpt/browser.py
index 3b3074a98560..51f0dbdba926 100644
--- a/tests/wpt/web-platform-tests/tools/wpt/browser.py
+++ b/tests/wpt/web-platform-tests/tools/wpt/browser.py
@@ -41,7 +41,7 @@ def find_binary(self, venv_path=None, channel=None):
         return NotImplemented
 
     @abstractmethod
-    def find_webdriver(self):
+    def find_webdriver(self, channel=None):
         """Find the binary of the WebDriver."""
         return NotImplemented
 
@@ -211,7 +211,7 @@ def find_certutil(self):
             return None
         return path
 
-    def find_webdriver(self):
+    def find_webdriver(self, channel=None):
         return find_executable("geckodriver")
 
     def get_version_and_channel(self, binary):
@@ -387,7 +387,7 @@ def install(self, dest=None, channel=None):
     def find_binary(self, venv_path=None, channel=None):
         raise NotImplementedError
 
-    def find_webdriver(self):
+    def find_webdriver(self, channel=None):
         raise NotImplementedError
 
     def install_webdriver(self, dest=None, channel=None):
@@ -441,7 +441,7 @@ def platform_string(self):
     def find_binary(self, venv_path=None, channel=None):
         raise NotImplementedError
 
-    def find_webdriver(self):
+    def find_webdriver(self, channel=None):
         return find_executable("chromedriver")
 
     def install_webdriver(self, dest=None, channel=None):
@@ -489,7 +489,7 @@ def install(self, dest=None, channel=None):
     def find_binary(self, venv_path=None, channel=None):
         raise NotImplementedError
 
-    def find_webdriver(self):
+    def find_webdriver(self, channel=None):
         return find_executable("chromedriver")
 
     def install_webdriver(self, dest=None, channel=None):
@@ -541,7 +541,7 @@ def platform_string(self):
     def find_binary(self, venv_path=None, channel=None):
         raise NotImplementedError
 
-    def find_webdriver(self):
+    def find_webdriver(self, channel=None):
         return find_executable("operadriver")
 
     def install_webdriver(self, dest=None, channel=None):
@@ -584,7 +584,7 @@ def install(self, dest=None, channel=None):
     def find_binary(self, venv_path=None, channel=None):
         raise NotImplementedError
 
-    def find_webdriver(self):
+    def find_webdriver(self, channel=None):
         return find_executable("MicrosoftWebDriver")
 
     def install_webdriver(self, dest=None, channel=None):
@@ -610,7 +610,7 @@ def install(self, dest=None, channel=None):
     def find_binary(self, venv_path=None, channel=None):
         raise NotImplementedError
 
-    def find_webdriver(self):
+    def find_webdriver(self, channel=None):
         return find_executable("IEDriverServer.exe")
 
     def install_webdriver(self, dest=None, channel=None):
@@ -635,8 +635,11 @@ def install(self, dest=None, channel=None):
     def find_binary(self, venv_path=None, channel=None):
         raise NotImplementedError
 
-    def find_webdriver(self):
-        return find_executable("safaridriver")
+    def find_webdriver(self, channel=None):
+        path = None
+        if channel == "preview":
+            path = "/Applications/Safari Technology Preview.app/Contents/MacOS"
+        return find_executable("safaridriver", path)
 
     def install_webdriver(self, dest=None, channel=None):
         raise NotImplementedError
@@ -695,7 +698,7 @@ def find_binary(self, venv_path=None, channel=None):
             path = find_executable("servo")
         return path
 
-    def find_webdriver(self):
+    def find_webdriver(self, channel=None):
         return None
 
     def install_webdriver(self, dest=None, channel=None):
@@ -719,7 +722,7 @@ def install(self, dest=None, channel=None):
     def find_binary(self, venev_path=None, channel=None):
         raise NotImplementedError
 
-    def find_webdriver(self):
+    def find_webdriver(self, channel=None):
         raise NotImplementedError
 
     def install_webdriver(self, dest=None, channel=None):
@@ -741,7 +744,7 @@ def install(self, dest=None, channel=None):
     def find_binary(self, venv_path=None, channel=None):
         return None
 
-    def find_webdriver(self):
+    def find_webdriver(self, channel=None):
         return None
 
     def install_webdriver(self, dest=None, channel=None):
diff --git a/tests/wpt/web-platform-tests/tools/wpt/install.py b/tests/wpt/web-platform-tests/tools/wpt/install.py
index 62c833aa3f0c..f588a4128458 100644
--- a/tests/wpt/web-platform-tests/tools/wpt/install.py
+++ b/tests/wpt/web-platform-tests/tools/wpt/install.py
@@ -6,6 +6,8 @@
 latest_channels = {
     'firefox': 'nightly',
     'chrome': 'dev',
+    'safari': 'preview',
+    'safari_webdriver': 'preview',
     'servo': 'nightly'
 }
 
diff --git a/tests/wpt/web-platform-tests/tools/wpt/run.py b/tests/wpt/web-platform-tests/tools/wpt/run.py
index d9a44fd37115..da01a816974b 100644
--- a/tests/wpt/web-platform-tests/tools/wpt/run.py
+++ b/tests/wpt/web-platform-tests/tools/wpt/run.py
@@ -371,7 +371,7 @@ def install(self, venv, channel=None):
 
     def setup_kwargs(self, kwargs):
         if kwargs["webdriver_binary"] is None:
-            webdriver_binary = self.browser.find_webdriver()
+            webdriver_binary = self.browser.find_webdriver(channel=kwargs["browser_channel"])
 
             if webdriver_binary is None:
                 raise WptrunError("Unable to locate safaridriver binary")
diff --git a/tests/wpt/web-platform-tests/tools/wptrunner/requirements.txt b/tests/wpt/web-platform-tests/tools/wptrunner/requirements.txt
index 0e71ed50411b..2ae1622a6a39 100644
--- a/tests/wpt/web-platform-tests/tools/wptrunner/requirements.txt
+++ b/tests/wpt/web-platform-tests/tools/wptrunner/requirements.txt
@@ -1,5 +1,5 @@
 html5lib == 1.0.1
 mozinfo == 0.10
-mozlog==3.8
+mozlog==3.9
 mozdebug == 0.1
 urllib3[secure]==1.23
diff --git a/tests/wpt/web-platform-tests/tools/wptserve/tests/functional/base.py b/tests/wpt/web-platform-tests/tools/wptserve/tests/functional/base.py
index f8331f5086d3..190e385f1020 100644
--- a/tests/wpt/web-platform-tests/tools/wptserve/tests/functional/base.py
+++ b/tests/wpt/web-platform-tests/tools/wptserve/tests/functional/base.py
@@ -9,7 +9,7 @@
 from six.moves.urllib.parse import urlencode, urlunsplit
 from six.moves.urllib.request import Request as BaseRequest
 from six.moves.urllib.request import urlopen
-from six import binary_type, iteritems
+from six import binary_type, iteritems, PY3
 
 from hyper import HTTP20Connection, tls
 import ssl
@@ -79,6 +79,11 @@ def request(self, path, query=None, method="GET", headers=None, body=None, auth=
 
         return urlopen(req)
 
+    def assert_multiple_headers(self, resp, name, values):
+        if PY3:
+            assert resp.info().get_all(name) == values
+        else:
+            assert resp.info()[name] == ", ".join(values)
 
 @pytest.mark.skipif(not wptserve.utils.http2_compatible(), reason="h2 server only works in python 2.7.15")
 class TestUsingH2Server:
diff --git a/tests/wpt/web-platform-tests/tools/wptserve/tests/functional/test_pipes.py b/tests/wpt/web-platform-tests/tools/wptserve/tests/functional/test_pipes.py
index fdac4537d64f..693cb82e2410 100644
--- a/tests/wpt/web-platform-tests/tools/wptserve/tests/functional/test_pipes.py
+++ b/tests/wpt/web-platform-tests/tools/wptserve/tests/functional/test_pipes.py
@@ -35,10 +35,9 @@ def test_multiple_same(self):
         resp = self.request("/document.txt", query="pipe=header(Content-Type,FAIL)|header(Content-Type,text/html)")
         self.assertEqual(resp.info()["Content-Type"], "text/html")
 
-    @pytest.mark.xfail(sys.version_info >= (3,), reason="wptserve only works on Py2")
     def test_multiple_append(self):
         resp = self.request("/document.txt", query="pipe=header(X-Test,1)|header(X-Test,2,True)")
-        self.assertEqual(resp.info()["X-Test"], "1, 2")
+        self.assert_multiple_headers(resp, "X-Test", ["1", "2"])
 
 class TestSlice(TestUsingServer):
     def test_both_bounds(self):
diff --git a/tests/wpt/web-platform-tests/webrtc/RTCDTMFSender-helper.js b/tests/wpt/web-platform-tests/webrtc/RTCDTMFSender-helper.js
index 1dd2bccb361d..84cc771dda28 100644
--- a/tests/wpt/web-platform-tests/webrtc/RTCDTMFSender-helper.js
+++ b/tests/wpt/web-platform-tests/webrtc/RTCDTMFSender-helper.js
@@ -109,12 +109,16 @@ function test_tone_change_events(testFunc, toneChanges, desc) {
         const now = Date.now();
         const duration = now - lastEventTime;
 
-        assert_approx_equals(duration, expectedDuration, 400,
+        // We check that the delay is at least the expected one, but
+        // system load may cause random delay, so we do not put any
+        // realistic upper bound on the timing of the event.
+        assert_between_inclusive(duration, expectedDuration,
+                                 expectedDuration + 4000,
           `Expect tonechange event for "${tone}" to be fired approximately after ${expectedDuration} milliseconds`);
 
         lastEventTime = now;
 
-        if(toneChanges.length === 0) {
+        if (toneChanges.length === 0) {
           // Wait for same duration as last expected duration + 100ms
           // before passing test in case there are new tone events fired,
           // in which case the test should fail.
diff --git a/tests/wpt/web-platform-tests/webrtc/RTCDTMFSender-ontonechange.https.html b/tests/wpt/web-platform-tests/webrtc/RTCDTMFSender-ontonechange.https.html
index 6beefb5287d6..ff6d117b3c75 100644
--- a/tests/wpt/web-platform-tests/webrtc/RTCDTMFSender-ontonechange.https.html
+++ b/tests/wpt/web-platform-tests/webrtc/RTCDTMFSender-ontonechange.https.html
@@ -161,13 +161,7 @@
   test_tone_change_events((t, dtmfSender) => {
     dtmfSender.addEventListener('tonechange', ev => {
       if(ev.tone === 'B') {
-        // Set a timeout to make sure the toneBuffer
-        // is changed after the tonechange event listener
-        // by test_tone_change_events is called.
-        // This is to correctly test the expected toneBuffer.
-        t.step_timeout(() => {
-          dtmfSender.insertDTMF('12', 100, 70);
-        }, 10);
+        dtmfSender.insertDTMF('12', 100, 70);
       }
     });
 
@@ -189,10 +183,8 @@
   test_tone_change_events((t, dtmfSender) => {
     dtmfSender.addEventListener('tonechange', ev => {
       if(ev.tone === 'B') {
-        t.step_timeout(() => {
-          dtmfSender.insertDTMF('12', 100, 70);
-          dtmfSender.insertDTMF('34', 100, 70);
-        }, 10);
+        dtmfSender.insertDTMF('12', 100, 70);
+        dtmfSender.insertDTMF('34', 100, 70);
       }
     });
 
@@ -213,9 +205,7 @@
   test_tone_change_events((t, dtmfSender) => {
     dtmfSender.addEventListener('tonechange', ev => {
       if(ev.tone === 'B') {
-        t.step_timeout(() => {
-          dtmfSender.insertDTMF('');
-        }, 10);
+        dtmfSender.insertDTMF('');
       }
     });