diff --git a/tests/ref/basic.list b/tests/ref/basic.list
index 05271c8b452..70760a141aa 100644
--- a/tests/ref/basic.list
+++ b/tests/ref/basic.list
@@ -179,7 +179,6 @@ flaky_cpu == linebreak_simple_a.html linebreak_simple_b.html
== margin_padding_inline_block_a.html margin_padding_inline_block_ref.html
== margins_inside_floats_a.html margins_inside_floats_ref.html
== marker_block_direction_placement_a.html marker_block_direction_placement_ref.html
-== negative_margins_a.html negative_margins_b.html
!= noteq_attr_exists_selector.html attr_exists_selector_ref.html
!= octicons_a.html octicons_ref.html
== ol_japanese_iroha_a.html ol_japanese_iroha_ref.html
diff --git a/tests/wpt/mozilla/meta/MANIFEST.json b/tests/wpt/mozilla/meta/MANIFEST.json
index a3749dea2ac..8357275b444 100644
--- a/tests/wpt/mozilla/meta/MANIFEST.json
+++ b/tests/wpt/mozilla/meta/MANIFEST.json
@@ -935,6 +935,18 @@
"url": "/_mozilla/css/negative_margin_uncle_a.html"
}
],
+ "css/negative_margins_a.html": [
+ {
+ "path": "css/negative_margins_a.html",
+ "references": [
+ [
+ "/_mozilla/css/negative_margins_b.html",
+ "=="
+ ]
+ ],
+ "url": "/_mozilla/css/negative_margins_a.html"
+ }
+ ],
"css/no-image.html": [
{
"path": "css/no-image.html",
@@ -4176,6 +4188,18 @@
"url": "/_mozilla/css/negative_margin_uncle_a.html"
}
],
+ "css/negative_margins_a.html": [
+ {
+ "path": "css/negative_margins_a.html",
+ "references": [
+ [
+ "/_mozilla/css/negative_margins_b.html",
+ "=="
+ ]
+ ],
+ "url": "/_mozilla/css/negative_margins_a.html"
+ }
+ ],
"css/no-image.html": [
{
"path": "css/no-image.html",
diff --git a/tests/ref/negative_margins_a.html b/tests/wpt/mozilla/tests/css/negative_margins_a.html
similarity index 77%
rename from tests/ref/negative_margins_a.html
rename to tests/wpt/mozilla/tests/css/negative_margins_a.html
index 7c3593b2820..71245dfec75 100644
--- a/tests/ref/negative_margins_a.html
+++ b/tests/wpt/mozilla/tests/css/negative_margins_a.html
@@ -1,6 +1,7 @@
+