diff --git a/tests/ref/basic.list b/tests/ref/basic.list
index 6166017d8de..f433c63acc1 100644
--- a/tests/ref/basic.list
+++ b/tests/ref/basic.list
@@ -35,7 +35,6 @@ prefs:"layout.writing-mode.enabled" == iframe/size_attributes_vertical_writing_m
== iframe/stacking_context_position_a.html iframe/stacking_context_position_ref.html
# inline_border_a.html inline_border_b.html
-!= linear_gradients_smoke_a.html linear_gradients_smoke_ref.html
flaky_cpu == linebreak_simple_a.html linebreak_simple_b.html
# Fails intermittently (#3636)
# == link_style_dynamic_addition.html link_style_dynamic_addition_ref.html
diff --git a/tests/wpt/mozilla/meta/MANIFEST.json b/tests/wpt/mozilla/meta/MANIFEST.json
index 39f7d3abe18..52614c7fa0c 100644
--- a/tests/wpt/mozilla/meta/MANIFEST.json
+++ b/tests/wpt/mozilla/meta/MANIFEST.json
@@ -2451,6 +2451,18 @@
"url": "/_mozilla/css/linear_gradients_reverse_a.html"
}
],
+ "css/linear_gradients_smoke_a.html": [
+ {
+ "path": "css/linear_gradients_smoke_a.html",
+ "references": [
+ [
+ "/_mozilla/css/linear_gradients_smoke_ref.html",
+ "!="
+ ]
+ ],
+ "url": "/_mozilla/css/linear_gradients_smoke_a.html"
+ }
+ ],
"css/linebreak_inline_span_a.html": [
{
"path": "css/linebreak_inline_span_a.html",
@@ -7612,6 +7624,18 @@
"url": "/_mozilla/css/linear_gradients_reverse_a.html"
}
],
+ "css/linear_gradients_smoke_a.html": [
+ {
+ "path": "css/linear_gradients_smoke_a.html",
+ "references": [
+ [
+ "/_mozilla/css/linear_gradients_smoke_ref.html",
+ "!="
+ ]
+ ],
+ "url": "/_mozilla/css/linear_gradients_smoke_a.html"
+ }
+ ],
"css/linebreak_inline_span_a.html": [
{
"path": "css/linebreak_inline_span_a.html",
diff --git a/tests/ref/linear_gradients_smoke_a.html b/tests/wpt/mozilla/tests/css/linear_gradients_smoke_a.html
similarity index 88%
rename from tests/ref/linear_gradients_smoke_a.html
rename to tests/wpt/mozilla/tests/css/linear_gradients_smoke_a.html
index 16c423595e5..6a5939b49eb 100644
--- a/tests/ref/linear_gradients_smoke_a.html
+++ b/tests/wpt/mozilla/tests/css/linear_gradients_smoke_a.html
@@ -2,6 +2,7 @@
+