diff --git a/tests/ref/basic.list b/tests/ref/basic.list
index a4d4802c469..0675b830704 100644
--- a/tests/ref/basic.list
+++ b/tests/ref/basic.list
@@ -221,7 +221,6 @@ flaky_cpu == linebreak_simple_a.html linebreak_simple_b.html
== outline_offset_a.html outline_offset_ref.html
== outlines_simple_a.html outlines_simple_ref.html
== outlines_wrap_a.html outlines_wrap_ref.html
-== outset.html outset_ref.html
!= outset_blackborder.html blackborder_ref.html
# Should be == with expected failure. See #2797
!= overconstrained_block.html overconstrained_block_ref.html
diff --git a/tests/wpt/mozilla/meta/MANIFEST.json b/tests/wpt/mozilla/meta/MANIFEST.json
index ffe083a7621..ff2dc29ae07 100644
--- a/tests/wpt/mozilla/meta/MANIFEST.json
+++ b/tests/wpt/mozilla/meta/MANIFEST.json
@@ -683,6 +683,18 @@
"url": "/_mozilla/css/flex_nochild.html"
}
],
+ "css/outset.html": [
+ {
+ "path": "css/outset.html",
+ "references": [
+ [
+ "/_mozilla/css/outset_ref.html",
+ "=="
+ ]
+ ],
+ "url": "/_mozilla/css/outset.html"
+ }
+ ],
"css/overflow_auto_stacking_order_a.html": [
{
"path": "css/overflow_auto_stacking_order_a.html",
@@ -3408,6 +3420,18 @@
"url": "/_mozilla/css/flex_nochild.html"
}
],
+ "css/outset.html": [
+ {
+ "path": "css/outset.html",
+ "references": [
+ [
+ "/_mozilla/css/outset_ref.html",
+ "=="
+ ]
+ ],
+ "url": "/_mozilla/css/outset.html"
+ }
+ ],
"css/overflow_auto_stacking_order_a.html": [
{
"path": "css/overflow_auto_stacking_order_a.html",
diff --git a/tests/ref/outset.html b/tests/wpt/mozilla/tests/css/outset.html
similarity index 95%
rename from tests/ref/outset.html
rename to tests/wpt/mozilla/tests/css/outset.html
index 74eded318fd..eda9943d41d 100644
--- a/tests/ref/outset.html
+++ b/tests/wpt/mozilla/tests/css/outset.html
@@ -1,6 +1,7 @@
+