diff --git a/tests/ref/basic.list b/tests/ref/basic.list
index a37977e278f..45e513de6c5 100644
--- a/tests/ref/basic.list
+++ b/tests/ref/basic.list
@@ -52,7 +52,6 @@ prefs:"layout.flex.enabled" == flex_row_direction.html flex_row_direction_ref.ht
== float_clearance_intrinsic_width_a.html float_clearance_intrinsic_width_ref.html
== float_overflow_area_a.html float_overflow_area_ref.html
== float_positioned_pseudo_stacking_context.html float_positioned_pseudo_stacking_context_ref.html
-== float_under_top_margin_a.html float_under_top_margin_ref.html
== floated_generated_content_a.html floated_generated_content_b.html
== floated_negative_margins_a.html floated_negative_margins_ref.html
== floated_table_with_margin_a.html floated_table_with_margin_ref.html
diff --git a/tests/wpt/mozilla/meta/MANIFEST.json b/tests/wpt/mozilla/meta/MANIFEST.json
index b24c3c8d1e0..e209c833af4 100644
--- a/tests/wpt/mozilla/meta/MANIFEST.json
+++ b/tests/wpt/mozilla/meta/MANIFEST.json
@@ -875,6 +875,18 @@
"url": "/_mozilla/css/float_table_a.html"
}
],
+ "css/float_under_top_margin_a.html": [
+ {
+ "path": "css/float_under_top_margin_a.html",
+ "references": [
+ [
+ "/_mozilla/css/float_under_top_margin_ref.html",
+ "=="
+ ]
+ ],
+ "url": "/_mozilla/css/float_under_top_margin_a.html"
+ }
+ ],
"css/floated_list_item_a.html": [
{
"path": "css/floated_list_item_a.html",
@@ -5004,6 +5016,18 @@
"url": "/_mozilla/css/float_table_a.html"
}
],
+ "css/float_under_top_margin_a.html": [
+ {
+ "path": "css/float_under_top_margin_a.html",
+ "references": [
+ [
+ "/_mozilla/css/float_under_top_margin_ref.html",
+ "=="
+ ]
+ ],
+ "url": "/_mozilla/css/float_under_top_margin_a.html"
+ }
+ ],
"css/floated_list_item_a.html": [
{
"path": "css/floated_list_item_a.html",
diff --git a/tests/ref/float_under_top_margin_a.html b/tests/wpt/mozilla/tests/css/float_under_top_margin_a.html
similarity index 84%
rename from tests/ref/float_under_top_margin_a.html
rename to tests/wpt/mozilla/tests/css/float_under_top_margin_a.html
index 5cf1fdbdbd4..ffe30dac16d 100644
--- a/tests/ref/float_under_top_margin_a.html
+++ b/tests/wpt/mozilla/tests/css/float_under_top_margin_a.html
@@ -1,6 +1,7 @@
+