diff --git a/tests/ref/basic.list b/tests/ref/basic.list
index 612b9235f62..6144aa1632a 100644
--- a/tests/ref/basic.list
+++ b/tests/ref/basic.list
@@ -185,7 +185,6 @@ flaky_cpu == linebreak_simple_a.html linebreak_simple_b.html
== min_width_simple_a.html min_width_simple_b.html
== minimum_line_height_a.html minimum_line_height_b.html
== mix_blend_mode_a.html mix_blend_mode_ref.html
-== multiple_css_class_a.html multiple_css_class_b.html
== negative_margins_a.html negative_margins_b.html
== no-image.html no-image-ref.html
== no_image_background_a.html no_image_background_ref.html
diff --git a/tests/wpt/mozilla/meta/MANIFEST.json b/tests/wpt/mozilla/meta/MANIFEST.json
index a6d5718547f..98c3596bd1b 100644
--- a/tests/wpt/mozilla/meta/MANIFEST.json
+++ b/tests/wpt/mozilla/meta/MANIFEST.json
@@ -839,6 +839,18 @@
"url": "/_mozilla/css/min_max_height_a.html"
}
],
+ "css/multiple_css_class_a.html": [
+ {
+ "path": "css/multiple_css_class_a.html",
+ "references": [
+ [
+ "/_mozilla/css/multiple_css_class_b.html",
+ "=="
+ ]
+ ],
+ "url": "/_mozilla/css/multiple_css_class_a.html"
+ }
+ ],
"css/negative_margin_uncle_a.html": [
{
"path": "css/negative_margin_uncle_a.html",
@@ -3948,6 +3960,18 @@
"url": "/_mozilla/css/min_max_height_a.html"
}
],
+ "css/multiple_css_class_a.html": [
+ {
+ "path": "css/multiple_css_class_a.html",
+ "references": [
+ [
+ "/_mozilla/css/multiple_css_class_b.html",
+ "=="
+ ]
+ ],
+ "url": "/_mozilla/css/multiple_css_class_a.html"
+ }
+ ],
"css/negative_margin_uncle_a.html": [
{
"path": "css/negative_margin_uncle_a.html",
diff --git a/tests/ref/multiple_css_class_a.html b/tests/wpt/mozilla/tests/css/multiple_css_class_a.html
similarity index 81%
rename from tests/ref/multiple_css_class_a.html
rename to tests/wpt/mozilla/tests/css/multiple_css_class_a.html
index bdca7589fdf..aaf1fbdbf1c 100644
--- a/tests/ref/multiple_css_class_a.html
+++ b/tests/wpt/mozilla/tests/css/multiple_css_class_a.html
@@ -1,5 +1,6 @@
+