diff --git a/tests/wpt/mozilla/meta/MANIFEST.json b/tests/wpt/mozilla/meta/MANIFEST.json
index 5aa73e95581..815909738ab 100644
--- a/tests/wpt/mozilla/meta/MANIFEST.json
+++ b/tests/wpt/mozilla/meta/MANIFEST.json
@@ -4432,6 +4432,30 @@
             "url": "/_mozilla/css/pseudo_element_restyle_no_rules.html"
           }
         ],
+        "css/pseudo_element_spacing_margin.html": [
+          {
+            "path": "css/pseudo_element_spacing_margin.html",
+            "references": [
+              [
+                "/_mozilla/css/pseudo_element_spacing_ref.html",
+                "=="
+              ]
+            ],
+            "url": "/_mozilla/css/pseudo_element_spacing_margin.html"
+          }
+        ],
+        "css/pseudo_element_spacing_padding.html": [
+          {
+            "path": "css/pseudo_element_spacing_padding.html",
+            "references": [
+              [
+                "/_mozilla/css/pseudo_element_spacing_ref.html",
+                "=="
+              ]
+            ],
+            "url": "/_mozilla/css/pseudo_element_spacing_padding.html"
+          }
+        ],
         "css/pseudo_inherit.html": [
           {
             "path": "css/pseudo_inherit.html",
@@ -13610,6 +13634,30 @@
           "url": "/_mozilla/css/pseudo_element_restyle_no_rules.html"
         }
       ],
+      "css/pseudo_element_spacing_margin.html": [
+        {
+          "path": "css/pseudo_element_spacing_margin.html",
+          "references": [
+            [
+              "/_mozilla/css/pseudo_element_spacing_ref.html",
+              "=="
+            ]
+          ],
+          "url": "/_mozilla/css/pseudo_element_spacing_margin.html"
+        }
+      ],
+      "css/pseudo_element_spacing_padding.html": [
+        {
+          "path": "css/pseudo_element_spacing_padding.html",
+          "references": [
+            [
+              "/_mozilla/css/pseudo_element_spacing_ref.html",
+              "=="
+            ]
+          ],
+          "url": "/_mozilla/css/pseudo_element_spacing_padding.html"
+        }
+      ],
       "css/pseudo_inherit.html": [
         {
           "path": "css/pseudo_inherit.html",
diff --git a/tests/wpt/mozilla/tests/css/pseudo_element_spacing_margin.html b/tests/wpt/mozilla/tests/css/pseudo_element_spacing_margin.html
new file mode 100644
index 00000000000..8ca773655a5
--- /dev/null
+++ b/tests/wpt/mozilla/tests/css/pseudo_element_spacing_margin.html
@@ -0,0 +1,31 @@
+<!DOCTYPE html>
+<html>
+<head>
+<link rel='match' href='pseudo_element_spacing_ref.html'>
+<style type="text/css">
+  span:before {
+    content:"a";
+    margin-right:5em;
+  }
+  span:after {
+    content:"c";
+    margin-left:5em;
+  }
+  #first {
+    margin-left:4em;
+    margin-right:4em;
+  }
+  #second:before {
+    margin-left:4em;
+  }
+  #second:after {
+    margin-right:4em;
+  }
+</style>
+</head>
+
+<body>
+    |<span id=first>b</span>|<br>
+    |<span id=second>b</span>|
+</body>
+</html>
diff --git a/tests/wpt/mozilla/tests/css/pseudo_element_spacing_padding.html b/tests/wpt/mozilla/tests/css/pseudo_element_spacing_padding.html
new file mode 100644
index 00000000000..63de712937b
--- /dev/null
+++ b/tests/wpt/mozilla/tests/css/pseudo_element_spacing_padding.html
@@ -0,0 +1,31 @@
+<!DOCTYPE html>
+<html>
+<head>
+<link rel='match' href='pseudo_element_spacing_ref.html'>
+<style type="text/css">
+  span:before {
+    content:"a";
+    padding-right:5em;
+  }
+  span:after {
+    content:"c";
+    padding-left:5em;
+  }
+  #first {
+    padding-left:4em;
+    padding-right:4em;
+  }
+  #second:before {
+    padding-left:4em;
+  }
+  #second:after {
+    padding-right:4em;
+  }
+</style>
+</head>
+
+<body>
+    |<span id=first>b</span>|<br>
+    |<span id=second>b</span>|
+</body>
+</html>
diff --git a/tests/wpt/mozilla/tests/css/pseudo_element_spacing_ref.html b/tests/wpt/mozilla/tests/css/pseudo_element_spacing_ref.html
new file mode 100644
index 00000000000..9eb5ee245cf
--- /dev/null
+++ b/tests/wpt/mozilla/tests/css/pseudo_element_spacing_ref.html
@@ -0,0 +1,19 @@
+<!DOCTYPE html>
+<html>
+<head><style type="text/css">
+  #first {
+    margin-left:4em;
+  }
+  #last {
+    margin-right:4em;
+  }
+  #central {
+    margin-left:5em;
+    margin-right:5em;
+  }
+</style></head>
+<body>
+    |<span id=first>a</span><span id=central>b</span><span id="last">c</span>|<br>
+    |<span id=first>a</span><span id=central>b</span><span id="last">c</span>|
+</body>
+</html>
