diff --git a/tests/ref/basic.list b/tests/ref/basic.list
index e6f5e86e9e2..89019a8c19d 100644
--- a/tests/ref/basic.list
+++ b/tests/ref/basic.list
@@ -160,7 +160,6 @@ prefs:"layout.writing-mode.enabled" == iframe/size_attributes_vertical_writing_m
== line_height_a.html line_height_ref.html
== line_height_float_placement_a.html line_height_float_placement_ref.html
!= linear_gradients_corners_a.html linear_gradients_corners_ref.html
-== linear_gradients_lengths_a.html linear_gradients_lengths_ref.html
== linear_gradients_parsing_a.html linear_gradients_parsing_ref.html
== linear_gradients_reverse_a.html linear_gradients_reverse_ref.html
!= linear_gradients_smoke_a.html linear_gradients_smoke_ref.html
diff --git a/tests/wpt/mozilla/meta/MANIFEST.json b/tests/wpt/mozilla/meta/MANIFEST.json
index 6984eba36e6..0326b9de106 100644
--- a/tests/wpt/mozilla/meta/MANIFEST.json
+++ b/tests/wpt/mozilla/meta/MANIFEST.json
@@ -851,6 +851,18 @@
"url": "/_mozilla/css/letter_spacing_a.html"
}
],
+ "css/linear_gradients_lengths_a.html": [
+ {
+ "path": "css/linear_gradients_lengths_a.html",
+ "references": [
+ [
+ "/_mozilla/css/linear_gradients_lengths_ref.html",
+ "=="
+ ]
+ ],
+ "url": "/_mozilla/css/linear_gradients_lengths_a.html"
+ }
+ ],
"css/max_width_float_simple_a.html": [
{
"path": "css/max_width_float_simple_a.html",
@@ -4128,6 +4140,18 @@
"url": "/_mozilla/css/letter_spacing_a.html"
}
],
+ "css/linear_gradients_lengths_a.html": [
+ {
+ "path": "css/linear_gradients_lengths_a.html",
+ "references": [
+ [
+ "/_mozilla/css/linear_gradients_lengths_ref.html",
+ "=="
+ ]
+ ],
+ "url": "/_mozilla/css/linear_gradients_lengths_a.html"
+ }
+ ],
"css/max_width_float_simple_a.html": [
{
"path": "css/max_width_float_simple_a.html",
diff --git a/tests/ref/linear_gradients_lengths_a.html b/tests/wpt/mozilla/tests/css/linear_gradients_lengths_a.html
similarity index 85%
rename from tests/ref/linear_gradients_lengths_a.html
rename to tests/wpt/mozilla/tests/css/linear_gradients_lengths_a.html
index 12d8fa03c15..7cc0c449f5f 100644
--- a/tests/ref/linear_gradients_lengths_a.html
+++ b/tests/wpt/mozilla/tests/css/linear_gradients_lengths_a.html
@@ -1,6 +1,7 @@
+