diff --git a/tests/wpt/mozilla/meta/MANIFEST.json b/tests/wpt/mozilla/meta/MANIFEST.json
index 434afa7e5a2..9ecaa48d559 100644
--- a/tests/wpt/mozilla/meta/MANIFEST.json
+++ b/tests/wpt/mozilla/meta/MANIFEST.json
@@ -11036,6 +11036,12 @@
      {}
     ]
    ],
+   "css/float-abspos.html": [
+    [
+     "/_mozilla/css/float-abspos.html",
+     {}
+    ]
+   ],
    "css/float_relative_to_position.html": [
     [
      "/_mozilla/css/float_relative_to_position.html",
@@ -20895,6 +20901,10 @@
    "2712a0a76b5eeb4d0f2b4a45277d04791a8ff206",
    "support"
   ],
+  "css/float-abspos.html": [
+   "d34a9ce0be290bc3c46aa80eb136a91460957346",
+   "testharness"
+  ],
   "css/float_clearance_a.html": [
    "372652bf4c345098f864cfc52ad0fb274308b22c",
    "reftest"
diff --git a/tests/wpt/mozilla/tests/css/float-abspos.html b/tests/wpt/mozilla/tests/css/float-abspos.html
new file mode 100644
index 00000000000..f691c1756f0
--- /dev/null
+++ b/tests/wpt/mozilla/tests/css/float-abspos.html
@@ -0,0 +1,20 @@
+<!doctype html>
+<meta charset="utf-8">
+<title>A positioned element's float value computes to "none"</title>
+<link rel="help" href="https://www.w3.org/TR/CSS21/visuren.html#dis-pos-flo">
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:emilio@crisal.io">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<div id="test" style="float: left"></div>
+<script>
+test(function() {
+  var elem = document.getElementById('test');
+  assert_equals(getComputedStyle(elem).float, "left");
+  elem.style.position = "absolute";
+  assert_equals(getComputedStyle(elem).float, "none");
+  elem.style.position = "";
+  assert_equals(getComputedStyle(elem).float, "left");
+  elem.style.position = "fixed";
+  assert_equals(getComputedStyle(elem).float, "none");
+}, "A positioned element's float value computes to none");
+</script>
