diff --git a/tests/ref/basic.list b/tests/ref/basic.list
index ece2890f2f5..fc1940bf0ae 100644
--- a/tests/ref/basic.list
+++ b/tests/ref/basic.list
@@ -213,7 +213,6 @@ flaky_cpu == linebreak_simple_a.html linebreak_simple_b.html
!= octicons_a.html octicons_ref.html
== ol_japanese_iroha_a.html ol_japanese_iroha_ref.html
!= ol_japanese_iroha_bullet_styles.html ol_japanese_iroha_ref.html
-== only_child_pseudo_a.html only_child_pseudo_b.html
== outline_offset_a.html outline_offset_ref.html
!= outset_blackborder.html blackborder_ref.html
# Should be == with expected failure. See #2797
diff --git a/tests/wpt/mozilla/meta/MANIFEST.json b/tests/wpt/mozilla/meta/MANIFEST.json
index 3f9e66f226a..15e0fdcfde2 100644
--- a/tests/wpt/mozilla/meta/MANIFEST.json
+++ b/tests/wpt/mozilla/meta/MANIFEST.json
@@ -695,6 +695,18 @@
"url": "/_mozilla/css/ol_simple_a.html"
}
],
+ "css/only_child_pseudo_a.html": [
+ {
+ "path": "css/only_child_pseudo_a.html",
+ "references": [
+ [
+ "/_mozilla/css/only_child_pseudo_b.html",
+ "=="
+ ]
+ ],
+ "url": "/_mozilla/css/only_child_pseudo_a.html"
+ }
+ ],
"css/only_of_type_pseudo_a.html": [
{
"path": "css/only_of_type_pseudo_a.html",
@@ -3504,6 +3516,18 @@
"url": "/_mozilla/css/ol_simple_a.html"
}
],
+ "css/only_child_pseudo_a.html": [
+ {
+ "path": "css/only_child_pseudo_a.html",
+ "references": [
+ [
+ "/_mozilla/css/only_child_pseudo_b.html",
+ "=="
+ ]
+ ],
+ "url": "/_mozilla/css/only_child_pseudo_a.html"
+ }
+ ],
"css/only_of_type_pseudo_a.html": [
{
"path": "css/only_of_type_pseudo_a.html",
diff --git a/tests/ref/only_child_pseudo_a.html b/tests/wpt/mozilla/tests/css/only_child_pseudo_a.html
similarity index 94%
rename from tests/ref/only_child_pseudo_a.html
rename to tests/wpt/mozilla/tests/css/only_child_pseudo_a.html
index 8eaf71f3fed..9ecf1f8a00b 100644
--- a/tests/ref/only_child_pseudo_a.html
+++ b/tests/wpt/mozilla/tests/css/only_child_pseudo_a.html
@@ -1,6 +1,7 @@
+
:only-child test