diff --git a/tests/ref/basic.list b/tests/ref/basic.list
index 094a3becc87..cdc448a8173 100644
--- a/tests/ref/basic.list
+++ b/tests/ref/basic.list
@@ -13,7 +13,6 @@ fragment=top != ../html/acid2.html acid2_ref.html
flaky_cpu == append_style_a.html append_style_b.html
# `?` and `#` in the name is a test for https://github.com/servo/servo/issues/3340
-== iframe/simple_inline_default.html iframe/simple_inline_default_ref.html
== iframe/simple_inline_height.html iframe/simple_inline_height_ref.html
== iframe/simple_inline_max.html iframe/simple_inline_max_ref.html
== iframe/simple_inline_min.html iframe/simple_inline_min_ref.html
diff --git a/tests/wpt/mozilla/meta/MANIFEST.json b/tests/wpt/mozilla/meta/MANIFEST.json
index a8fec7d5d03..654239d05b0 100644
--- a/tests/wpt/mozilla/meta/MANIFEST.json
+++ b/tests/wpt/mozilla/meta/MANIFEST.json
@@ -1675,6 +1675,18 @@
"url": "/_mozilla/css/iframe/simple.html"
}
],
+ "css/iframe/simple_inline_default.html": [
+ {
+ "path": "css/iframe/simple_inline_default.html",
+ "references": [
+ [
+ "/_mozilla/css/iframe/simple_inline_default_ref.html",
+ "=="
+ ]
+ ],
+ "url": "/_mozilla/css/iframe/simple_inline_default.html"
+ }
+ ],
"css/image_rendering_auto_a.html": [
{
"path": "css/image_rendering_auto_a.html",
@@ -7224,6 +7236,18 @@
"url": "/_mozilla/css/iframe/simple.html"
}
],
+ "css/iframe/simple_inline_default.html": [
+ {
+ "path": "css/iframe/simple_inline_default.html",
+ "references": [
+ [
+ "/_mozilla/css/iframe/simple_inline_default_ref.html",
+ "=="
+ ]
+ ],
+ "url": "/_mozilla/css/iframe/simple_inline_default.html"
+ }
+ ],
"css/image_rendering_auto_a.html": [
{
"path": "css/image_rendering_auto_a.html",
diff --git a/tests/ref/iframe/simple_inline_default.html b/tests/wpt/mozilla/tests/css/iframe/simple_inline_default.html
similarity index 81%
rename from tests/ref/iframe/simple_inline_default.html
rename to tests/wpt/mozilla/tests/css/iframe/simple_inline_default.html
index c4d268304f5..e5777b0001a 100644
--- a/tests/ref/iframe/simple_inline_default.html
+++ b/tests/wpt/mozilla/tests/css/iframe/simple_inline_default.html
@@ -1,4 +1,5 @@
+