diff --git a/tests/ref/basic.list b/tests/ref/basic.list
index 0153d60f0ec..e269b55cf93 100644
--- a/tests/ref/basic.list
+++ b/tests/ref/basic.list
@@ -37,7 +37,6 @@ flaky_cpu == append_style_a.html append_style_b.html
== counters_simple_a.html counters_simple_ref.html
== empty_cells_a.html empty_cells_ref.html
== filter_opacity_a.html filter_opacity_ref.html
-== first_child_pseudo_a.html first_child_pseudo_b.html
== fixed_width_overrides_child_intrinsic_width_a.html fixed_width_overrides_child_intrinsic_width_ref.html
prefs:"layout.flex-direction.enabled,layout.flex.enabled" == flex_column_direction.html flex_column_direction_ref.html
prefs:"layout.flex.enabled" == flex_row_direction.html flex_row_direction_ref.html
diff --git a/tests/wpt/mozilla/meta/MANIFEST.json b/tests/wpt/mozilla/meta/MANIFEST.json
index 5763a9ce4b2..f59a099f17c 100644
--- a/tests/wpt/mozilla/meta/MANIFEST.json
+++ b/tests/wpt/mozilla/meta/MANIFEST.json
@@ -887,6 +887,18 @@
"url": "/_mozilla/css/filter_sepia_a.html"
}
],
+ "css/first_child_pseudo_a.html": [
+ {
+ "path": "css/first_child_pseudo_a.html",
+ "references": [
+ [
+ "/_mozilla/css/first_child_pseudo_b.html",
+ "=="
+ ]
+ ],
+ "url": "/_mozilla/css/first_child_pseudo_a.html"
+ }
+ ],
"css/first_of_type_pseudo_a.html": [
{
"path": "css/first_of_type_pseudo_a.html",
@@ -5172,6 +5184,18 @@
"url": "/_mozilla/css/filter_sepia_a.html"
}
],
+ "css/first_child_pseudo_a.html": [
+ {
+ "path": "css/first_child_pseudo_a.html",
+ "references": [
+ [
+ "/_mozilla/css/first_child_pseudo_b.html",
+ "=="
+ ]
+ ],
+ "url": "/_mozilla/css/first_child_pseudo_a.html"
+ }
+ ],
"css/first_of_type_pseudo_a.html": [
{
"path": "css/first_of_type_pseudo_a.html",
diff --git a/tests/ref/first_child_pseudo_a.html b/tests/wpt/mozilla/tests/css/first_child_pseudo_a.html
similarity index 93%
rename from tests/ref/first_child_pseudo_a.html
rename to tests/wpt/mozilla/tests/css/first_child_pseudo_a.html
index c2eabab18b9..c32fe0857fe 100644
--- a/tests/ref/first_child_pseudo_a.html
+++ b/tests/wpt/mozilla/tests/css/first_child_pseudo_a.html
@@ -1,6 +1,7 @@
+
:first-child test