diff --git a/tests/ref/basic.list b/tests/ref/basic.list
index 899b6b5d1d9..91e7028a667 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
-!= inset_blackborder.html blackborder_ref.html
== jpeg_normal.html jpeg_ref.html
== jpeg_progressive.html jpeg_ref.html
== legacy_cellspacing_attribute_a.html border_spacing_ref.html
@@ -55,7 +54,6 @@ 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
-!= outset_blackborder.html blackborder_ref.html
# Should be == with expected failure. See #2797
!= overconstrained_block.html overconstrained_block_ref.html
== overflow_auto.html overflow_simple_b.html
diff --git a/tests/wpt/mozilla/meta/MANIFEST.json b/tests/wpt/mozilla/meta/MANIFEST.json
index d951ace7c1a..25ba21a1b61 100644
--- a/tests/wpt/mozilla/meta/MANIFEST.json
+++ b/tests/wpt/mozilla/meta/MANIFEST.json
@@ -2147,6 +2147,18 @@
"url": "/_mozilla/css/inset.html"
}
],
+ "css/inset_blackborder.html": [
+ {
+ "path": "css/inset_blackborder.html",
+ "references": [
+ [
+ "/_mozilla/css/blackborder_ref.html",
+ "!="
+ ]
+ ],
+ "url": "/_mozilla/css/inset_blackborder.html"
+ }
+ ],
"css/issue-1324.html": [
{
"path": "css/issue-1324.html",
@@ -2759,6 +2771,18 @@
"url": "/_mozilla/css/outset.html"
}
],
+ "css/outset_blackborder.html": [
+ {
+ "path": "css/outset_blackborder.html",
+ "references": [
+ [
+ "/_mozilla/css/blackborder_ref.html",
+ "!="
+ ]
+ ],
+ "url": "/_mozilla/css/outset_blackborder.html"
+ }
+ ],
"css/overflow_auto_stacking_order_a.html": [
{
"path": "css/overflow_auto_stacking_order_a.html",
@@ -7164,6 +7188,18 @@
"url": "/_mozilla/css/inset.html"
}
],
+ "css/inset_blackborder.html": [
+ {
+ "path": "css/inset_blackborder.html",
+ "references": [
+ [
+ "/_mozilla/css/blackborder_ref.html",
+ "!="
+ ]
+ ],
+ "url": "/_mozilla/css/inset_blackborder.html"
+ }
+ ],
"css/issue-1324.html": [
{
"path": "css/issue-1324.html",
@@ -7776,6 +7812,18 @@
"url": "/_mozilla/css/outset.html"
}
],
+ "css/outset_blackborder.html": [
+ {
+ "path": "css/outset_blackborder.html",
+ "references": [
+ [
+ "/_mozilla/css/blackborder_ref.html",
+ "!="
+ ]
+ ],
+ "url": "/_mozilla/css/outset_blackborder.html"
+ }
+ ],
"css/overflow_auto_stacking_order_a.html": [
{
"path": "css/overflow_auto_stacking_order_a.html",
diff --git a/tests/ref/blackborder_ref.html b/tests/wpt/mozilla/tests/css/blackborder_ref.html
similarity index 100%
rename from tests/ref/blackborder_ref.html
rename to tests/wpt/mozilla/tests/css/blackborder_ref.html
diff --git a/tests/ref/inset_blackborder.html b/tests/wpt/mozilla/tests/css/inset_blackborder.html
similarity index 83%
rename from tests/ref/inset_blackborder.html
rename to tests/wpt/mozilla/tests/css/inset_blackborder.html
index ffacd8a7855..565760bedc2 100644
--- a/tests/ref/inset_blackborder.html
+++ b/tests/wpt/mozilla/tests/css/inset_blackborder.html
@@ -1,4 +1,5 @@
+