diff --git a/tests/ref/basic.list b/tests/ref/basic.list
index 4d8209c12d5..2d1f09c47b4 100644
--- a/tests/ref/basic.list
+++ b/tests/ref/basic.list
@@ -38,21 +38,10 @@ prefs:"layout.writing-mode.enabled" == iframe/size_attributes_vertical_writing_m
 flaky_cpu == linebreak_simple_a.html linebreak_simple_b.html
 # Fails intermittently (#3636)
 # == link_style_dynamic_addition.html link_style_dynamic_addition_ref.html
-== list_style_position_a.html list_style_position_ref.html
-!= list_style_type_a.html list_style_type_ref.html
-== margin_a.html margin_b.html
-== marker_block_direction_placement_a.html marker_block_direction_placement_ref.html
-!= noteq_attr_exists_selector.html attr_exists_selector_ref.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
 # Should be == with expected failure. See #2797
 != overconstrained_block.html overconstrained_block_ref.html
-== overflow_auto.html overflow_simple_b.html
 # Should be ==?
 != overflow_position_abs_inside_normal_a.html overflow_position_abs_inside_normal_b.html
-== overflow_scroll.html overflow_simple_b.html
-== overflow_simple_a.html overflow_simple_b.html
 resolution=300x300,device-pixel-ratio=2 != pixel_snapping_border_a.html pixel_snapping_border_ref.html
 resolution=300x300,device-pixel-ratio=2 != pixel_snapping_position_a.html pixel_snapping_position_ref.html
 # commented out because multiple layers don't work with reftests --pcwalton
diff --git a/tests/wpt/mozilla/meta/MANIFEST.json b/tests/wpt/mozilla/meta/MANIFEST.json
index fb9483e0ece..b865a87d4ca 100644
--- a/tests/wpt/mozilla/meta/MANIFEST.json
+++ b/tests/wpt/mozilla/meta/MANIFEST.json
@@ -206,6 +206,10 @@
               [
                 "/_mozilla/css/attr_exists_selector_ref.html",
                 "=="
+              ],
+              [
+                "/_mozilla/css/noteq_attr_exists_selector.html",
+                "!="
               ]
             ],
             "url": "/_mozilla/css/attr_exists_selector.html"
@@ -2523,6 +2527,30 @@
             "url": "/_mozilla/css/list_style_image_sizing_a.html"
           }
         ],
+        "css/list_style_position_a.html": [
+          {
+            "path": "css/list_style_position_a.html",
+            "references": [
+              [
+                "/_mozilla/css/list_style_position_ref.html",
+                "=="
+              ]
+            ],
+            "url": "/_mozilla/css/list_style_position_a.html"
+          }
+        ],
+        "css/list_style_type_a.html": [
+          {
+            "path": "css/list_style_type_a.html",
+            "references": [
+              [
+                "/_mozilla/css/list_style_type_ref.html",
+                "!="
+              ]
+            ],
+            "url": "/_mozilla/css/list_style_type_a.html"
+          }
+        ],
         "css/many_brs_a.html": [
           {
             "path": "css/many_brs_a.html",
@@ -2535,6 +2563,18 @@
             "url": "/_mozilla/css/many_brs_a.html"
           }
         ],
+        "css/margin_a.html": [
+          {
+            "path": "css/margin_a.html",
+            "references": [
+              [
+                "/_mozilla/css/margin_b.html",
+                "=="
+              ]
+            ],
+            "url": "/_mozilla/css/margin_a.html"
+          }
+        ],
         "css/margin_padding_inline_block_a.html": [
           {
             "path": "css/margin_padding_inline_block_a.html",
@@ -2559,6 +2599,18 @@
             "url": "/_mozilla/css/margins_inside_floats_a.html"
           }
         ],
+        "css/marker_block_direction_placement_a.html": [
+          {
+            "path": "css/marker_block_direction_placement_a.html",
+            "references": [
+              [
+                "/_mozilla/css/marker_block_direction_placement_ref.html",
+                "=="
+              ]
+            ],
+            "url": "/_mozilla/css/marker_block_direction_placement_a.html"
+          }
+        ],
         "css/max_width_float_simple_a.html": [
           {
             "path": "css/max_width_float_simple_a.html",
@@ -2775,6 +2827,42 @@
             "url": "/_mozilla/css/object_element_a.html"
           }
         ],
+        "css/octicons_a.html": [
+          {
+            "path": "css/octicons_a.html",
+            "references": [
+              [
+                "/_mozilla/css/octicons_ref.html",
+                "!="
+              ]
+            ],
+            "url": "/_mozilla/css/octicons_a.html"
+          }
+        ],
+        "css/ol_japanese_iroha_a.html": [
+          {
+            "path": "css/ol_japanese_iroha_a.html",
+            "references": [
+              [
+                "/_mozilla/css/ol_japanese_iroha_ref.html",
+                "=="
+              ]
+            ],
+            "url": "/_mozilla/css/ol_japanese_iroha_a.html"
+          }
+        ],
+        "css/ol_japanese_iroha_bullet_styles.html": [
+          {
+            "path": "css/ol_japanese_iroha_bullet_styles.html",
+            "references": [
+              [
+                "/_mozilla/css/ol_japanese_iroha_ref.html",
+                "!="
+              ]
+            ],
+            "url": "/_mozilla/css/ol_japanese_iroha_bullet_styles.html"
+          }
+        ],
         "css/ol_simple_a.html": [
           {
             "path": "css/ol_simple_a.html",
@@ -2895,6 +2983,18 @@
             "url": "/_mozilla/css/outset_blackborder.html"
           }
         ],
+        "css/overflow_auto.html": [
+          {
+            "path": "css/overflow_auto.html",
+            "references": [
+              [
+                "/_mozilla/css/overflow_simple_b.html",
+                "=="
+              ]
+            ],
+            "url": "/_mozilla/css/overflow_auto.html"
+          }
+        ],
         "css/overflow_auto_stacking_order_a.html": [
           {
             "path": "css/overflow_auto_stacking_order_a.html",
@@ -2943,6 +3043,30 @@
             "url": "/_mozilla/css/overflow_position_rel_inline_block.html"
           }
         ],
+        "css/overflow_scroll.html": [
+          {
+            "path": "css/overflow_scroll.html",
+            "references": [
+              [
+                "/_mozilla/css/overflow_simple_b.html",
+                "=="
+              ]
+            ],
+            "url": "/_mozilla/css/overflow_scroll.html"
+          }
+        ],
+        "css/overflow_simple_a.html": [
+          {
+            "path": "css/overflow_simple_a.html",
+            "references": [
+              [
+                "/_mozilla/css/overflow_simple_b.html",
+                "=="
+              ]
+            ],
+            "url": "/_mozilla/css/overflow_simple_a.html"
+          }
+        ],
         "css/overflow_wrap_a.html": [
           {
             "path": "css/overflow_wrap_a.html",
@@ -5415,6 +5539,10 @@
             [
               "/_mozilla/css/attr_exists_selector_ref.html",
               "=="
+            ],
+            [
+              "/_mozilla/css/noteq_attr_exists_selector.html",
+              "!="
             ]
           ],
           "url": "/_mozilla/css/attr_exists_selector.html"
@@ -7732,6 +7860,30 @@
           "url": "/_mozilla/css/list_style_image_sizing_a.html"
         }
       ],
+      "css/list_style_position_a.html": [
+        {
+          "path": "css/list_style_position_a.html",
+          "references": [
+            [
+              "/_mozilla/css/list_style_position_ref.html",
+              "=="
+            ]
+          ],
+          "url": "/_mozilla/css/list_style_position_a.html"
+        }
+      ],
+      "css/list_style_type_a.html": [
+        {
+          "path": "css/list_style_type_a.html",
+          "references": [
+            [
+              "/_mozilla/css/list_style_type_ref.html",
+              "!="
+            ]
+          ],
+          "url": "/_mozilla/css/list_style_type_a.html"
+        }
+      ],
       "css/many_brs_a.html": [
         {
           "path": "css/many_brs_a.html",
@@ -7744,6 +7896,18 @@
           "url": "/_mozilla/css/many_brs_a.html"
         }
       ],
+      "css/margin_a.html": [
+        {
+          "path": "css/margin_a.html",
+          "references": [
+            [
+              "/_mozilla/css/margin_b.html",
+              "=="
+            ]
+          ],
+          "url": "/_mozilla/css/margin_a.html"
+        }
+      ],
       "css/margin_padding_inline_block_a.html": [
         {
           "path": "css/margin_padding_inline_block_a.html",
@@ -7768,6 +7932,18 @@
           "url": "/_mozilla/css/margins_inside_floats_a.html"
         }
       ],
+      "css/marker_block_direction_placement_a.html": [
+        {
+          "path": "css/marker_block_direction_placement_a.html",
+          "references": [
+            [
+              "/_mozilla/css/marker_block_direction_placement_ref.html",
+              "=="
+            ]
+          ],
+          "url": "/_mozilla/css/marker_block_direction_placement_a.html"
+        }
+      ],
       "css/max_width_float_simple_a.html": [
         {
           "path": "css/max_width_float_simple_a.html",
@@ -7984,6 +8160,42 @@
           "url": "/_mozilla/css/object_element_a.html"
         }
       ],
+      "css/octicons_a.html": [
+        {
+          "path": "css/octicons_a.html",
+          "references": [
+            [
+              "/_mozilla/css/octicons_ref.html",
+              "!="
+            ]
+          ],
+          "url": "/_mozilla/css/octicons_a.html"
+        }
+      ],
+      "css/ol_japanese_iroha_a.html": [
+        {
+          "path": "css/ol_japanese_iroha_a.html",
+          "references": [
+            [
+              "/_mozilla/css/ol_japanese_iroha_ref.html",
+              "=="
+            ]
+          ],
+          "url": "/_mozilla/css/ol_japanese_iroha_a.html"
+        }
+      ],
+      "css/ol_japanese_iroha_bullet_styles.html": [
+        {
+          "path": "css/ol_japanese_iroha_bullet_styles.html",
+          "references": [
+            [
+              "/_mozilla/css/ol_japanese_iroha_ref.html",
+              "!="
+            ]
+          ],
+          "url": "/_mozilla/css/ol_japanese_iroha_bullet_styles.html"
+        }
+      ],
       "css/ol_simple_a.html": [
         {
           "path": "css/ol_simple_a.html",
@@ -8104,6 +8316,18 @@
           "url": "/_mozilla/css/outset_blackborder.html"
         }
       ],
+      "css/overflow_auto.html": [
+        {
+          "path": "css/overflow_auto.html",
+          "references": [
+            [
+              "/_mozilla/css/overflow_simple_b.html",
+              "=="
+            ]
+          ],
+          "url": "/_mozilla/css/overflow_auto.html"
+        }
+      ],
       "css/overflow_auto_stacking_order_a.html": [
         {
           "path": "css/overflow_auto_stacking_order_a.html",
@@ -8152,6 +8376,30 @@
           "url": "/_mozilla/css/overflow_position_rel_inline_block.html"
         }
       ],
+      "css/overflow_scroll.html": [
+        {
+          "path": "css/overflow_scroll.html",
+          "references": [
+            [
+              "/_mozilla/css/overflow_simple_b.html",
+              "=="
+            ]
+          ],
+          "url": "/_mozilla/css/overflow_scroll.html"
+        }
+      ],
+      "css/overflow_simple_a.html": [
+        {
+          "path": "css/overflow_simple_a.html",
+          "references": [
+            [
+              "/_mozilla/css/overflow_simple_b.html",
+              "=="
+            ]
+          ],
+          "url": "/_mozilla/css/overflow_simple_a.html"
+        }
+      ],
       "css/overflow_wrap_a.html": [
         {
           "path": "css/overflow_wrap_a.html",
diff --git a/tests/wpt/mozilla/tests/css/attr_exists_selector.html b/tests/wpt/mozilla/tests/css/attr_exists_selector.html
index a40f01e361d..9290ff83863 100644
--- a/tests/wpt/mozilla/tests/css/attr_exists_selector.html
+++ b/tests/wpt/mozilla/tests/css/attr_exists_selector.html
@@ -3,6 +3,7 @@
   <head>
     <title>Attribute exists selector: [foo] and [*|foo]</title>
     <link rel=match href=attr_exists_selector_ref.html>
+    <link rel=mismatch href=noteq_attr_exists_selector.html>
     <style>
       p[data-green] { color: green }
       p[*|data-red] { color: red }
diff --git a/tests/ref/fonts/octicons/LICENSE.txt b/tests/wpt/mozilla/tests/css/fonts/octicons/LICENSE.txt
similarity index 100%
rename from tests/ref/fonts/octicons/LICENSE.txt
rename to tests/wpt/mozilla/tests/css/fonts/octicons/LICENSE.txt
diff --git a/tests/ref/fonts/octicons/octicons.ttf b/tests/wpt/mozilla/tests/css/fonts/octicons/octicons.ttf
similarity index 100%
rename from tests/ref/fonts/octicons/octicons.ttf
rename to tests/wpt/mozilla/tests/css/fonts/octicons/octicons.ttf
diff --git a/tests/ref/fonts/takao-p-gothic/COPYING.html b/tests/wpt/mozilla/tests/css/fonts/takao-p-gothic/COPYING.html
similarity index 100%
rename from tests/ref/fonts/takao-p-gothic/COPYING.html
rename to tests/wpt/mozilla/tests/css/fonts/takao-p-gothic/COPYING.html
diff --git a/tests/ref/fonts/takao-p-gothic/TakaoPGothic.ttf b/tests/wpt/mozilla/tests/css/fonts/takao-p-gothic/TakaoPGothic.ttf
similarity index 100%
rename from tests/ref/fonts/takao-p-gothic/TakaoPGothic.ttf
rename to tests/wpt/mozilla/tests/css/fonts/takao-p-gothic/TakaoPGothic.ttf
diff --git a/tests/ref/list_style_position_a.html b/tests/wpt/mozilla/tests/css/list_style_position_a.html
similarity index 89%
rename from tests/ref/list_style_position_a.html
rename to tests/wpt/mozilla/tests/css/list_style_position_a.html
index eb32fb5de0e..63394c0c9f2 100644
--- a/tests/ref/list_style_position_a.html
+++ b/tests/wpt/mozilla/tests/css/list_style_position_a.html
@@ -5,6 +5,7 @@
 -->
 <html>
 <head>
+<link rel=match href=list_style_position_ref.html>
 <style>
 ul {
     margin: 0;
diff --git a/tests/ref/list_style_position_ref.html b/tests/wpt/mozilla/tests/css/list_style_position_ref.html
similarity index 100%
rename from tests/ref/list_style_position_ref.html
rename to tests/wpt/mozilla/tests/css/list_style_position_ref.html
diff --git a/tests/ref/list_style_type_a.html b/tests/wpt/mozilla/tests/css/list_style_type_a.html
similarity index 85%
rename from tests/ref/list_style_type_a.html
rename to tests/wpt/mozilla/tests/css/list_style_type_a.html
index f0bad6fde52..1d6a61098d7 100644
--- a/tests/ref/list_style_type_a.html
+++ b/tests/wpt/mozilla/tests/css/list_style_type_a.html
@@ -5,6 +5,7 @@
 -->
 <html>
 <head>
+<link rel=mismatch href=list_style_type_ref.html>
 <style>
 li {
     list-style: square;
diff --git a/tests/ref/list_style_type_ref.html b/tests/wpt/mozilla/tests/css/list_style_type_ref.html
similarity index 100%
rename from tests/ref/list_style_type_ref.html
rename to tests/wpt/mozilla/tests/css/list_style_type_ref.html
diff --git a/tests/ref/margin_a.html b/tests/wpt/mozilla/tests/css/margin_a.html
similarity index 97%
rename from tests/ref/margin_a.html
rename to tests/wpt/mozilla/tests/css/margin_a.html
index fb477aa30d9..d56dd85c2a2 100644
--- a/tests/ref/margin_a.html
+++ b/tests/wpt/mozilla/tests/css/margin_a.html
@@ -1,5 +1,6 @@
 <html>
   <head>
+    <link rel=match href=margin_b.html>
     <title>margin</title>
     <style>
       html {
diff --git a/tests/ref/margin_b.html b/tests/wpt/mozilla/tests/css/margin_b.html
similarity index 100%
rename from tests/ref/margin_b.html
rename to tests/wpt/mozilla/tests/css/margin_b.html
diff --git a/tests/ref/marker_block_direction_placement_a.html b/tests/wpt/mozilla/tests/css/marker_block_direction_placement_a.html
similarity index 67%
rename from tests/ref/marker_block_direction_placement_a.html
rename to tests/wpt/mozilla/tests/css/marker_block_direction_placement_a.html
index a5e884245fb..53fd30e113e 100644
--- a/tests/ref/marker_block_direction_placement_a.html
+++ b/tests/wpt/mozilla/tests/css/marker_block_direction_placement_a.html
@@ -1,4 +1,5 @@
 <!DOCTYPE html>
+<link rel=match href=marker_block_direction_placement_ref.html>
 <style>
 body, ol, p {
     margin: 0;
diff --git a/tests/ref/marker_block_direction_placement_ref.html b/tests/wpt/mozilla/tests/css/marker_block_direction_placement_ref.html
similarity index 100%
rename from tests/ref/marker_block_direction_placement_ref.html
rename to tests/wpt/mozilla/tests/css/marker_block_direction_placement_ref.html
diff --git a/tests/ref/noteq_attr_exists_selector.html b/tests/wpt/mozilla/tests/css/noteq_attr_exists_selector.html
similarity index 100%
rename from tests/ref/noteq_attr_exists_selector.html
rename to tests/wpt/mozilla/tests/css/noteq_attr_exists_selector.html
diff --git a/tests/ref/octicons_a.html b/tests/wpt/mozilla/tests/css/octicons_a.html
similarity index 82%
rename from tests/ref/octicons_a.html
rename to tests/wpt/mozilla/tests/css/octicons_a.html
index eb3a4a97b82..61d70be6d78 100644
--- a/tests/ref/octicons_a.html
+++ b/tests/wpt/mozilla/tests/css/octicons_a.html
@@ -1,6 +1,7 @@
 <!DOCTYPE html>
 <head>
 <meta charset="utf-8">
+<link rel=mismatch href=octicons_ref.html>
 <style>
 @font-face {
     font-family: 'Octicons';
diff --git a/tests/ref/octicons_ref.html b/tests/wpt/mozilla/tests/css/octicons_ref.html
similarity index 100%
rename from tests/ref/octicons_ref.html
rename to tests/wpt/mozilla/tests/css/octicons_ref.html
diff --git a/tests/ref/ol_japanese_iroha_a.html b/tests/wpt/mozilla/tests/css/ol_japanese_iroha_a.html
similarity index 90%
rename from tests/ref/ol_japanese_iroha_a.html
rename to tests/wpt/mozilla/tests/css/ol_japanese_iroha_a.html
index 8c1aedd9965..2a20d40f01d 100644
--- a/tests/ref/ol_japanese_iroha_a.html
+++ b/tests/wpt/mozilla/tests/css/ol_japanese_iroha_a.html
@@ -2,6 +2,7 @@
 <html>
 <head>
 <!-- Tests that Japanese iroha ordering works in list items. -->
+<link rel=match href=ol_japanese_iroha_ref.html>
 <style>
 @font-face {
     font-family: TakaoPGothic;
diff --git a/tests/ref/ol_japanese_iroha_bullet_styles.html b/tests/wpt/mozilla/tests/css/ol_japanese_iroha_bullet_styles.html
similarity index 91%
rename from tests/ref/ol_japanese_iroha_bullet_styles.html
rename to tests/wpt/mozilla/tests/css/ol_japanese_iroha_bullet_styles.html
index 0ed76f5c871..9db8f28dbd4 100644
--- a/tests/ref/ol_japanese_iroha_bullet_styles.html
+++ b/tests/wpt/mozilla/tests/css/ol_japanese_iroha_bullet_styles.html
@@ -2,6 +2,7 @@
 <html>
 <head>
 <!-- Ensures that U+3044, U+308D, U+306F, and U+306B are all supported in the current font. -->
+<link rel=mismatch href=ol_japanese_iroha_ref.html>
 <style>
 @font-face {
     font-family: TakaoPGothic;
diff --git a/tests/ref/ol_japanese_iroha_ref.html b/tests/wpt/mozilla/tests/css/ol_japanese_iroha_ref.html
similarity index 100%
rename from tests/ref/ol_japanese_iroha_ref.html
rename to tests/wpt/mozilla/tests/css/ol_japanese_iroha_ref.html
diff --git a/tests/ref/overflow_auto.html b/tests/wpt/mozilla/tests/css/overflow_auto.html
similarity index 86%
rename from tests/ref/overflow_auto.html
rename to tests/wpt/mozilla/tests/css/overflow_auto.html
index 29eb7e2e2c1..3529fd29131 100644
--- a/tests/ref/overflow_auto.html
+++ b/tests/wpt/mozilla/tests/css/overflow_auto.html
@@ -1,5 +1,6 @@
 <html>
   <head>
+    <link rel=match href=overflow_simple_b.html>
     <style>
       #first {
       height: 100px;
diff --git a/tests/ref/overflow_scroll.html b/tests/wpt/mozilla/tests/css/overflow_scroll.html
similarity index 86%
rename from tests/ref/overflow_scroll.html
rename to tests/wpt/mozilla/tests/css/overflow_scroll.html
index 26c333f4efe..bf32fbc01d1 100644
--- a/tests/ref/overflow_scroll.html
+++ b/tests/wpt/mozilla/tests/css/overflow_scroll.html
@@ -1,5 +1,6 @@
 <html>
   <head>
+    <link rel=match href=overflow_simple_b.html>
     <style>
       #first {
       height: 100px;
diff --git a/tests/ref/overflow_simple_a.html b/tests/wpt/mozilla/tests/css/overflow_simple_a.html
similarity index 86%
rename from tests/ref/overflow_simple_a.html
rename to tests/wpt/mozilla/tests/css/overflow_simple_a.html
index 9b8b53eff89..96951aa172f 100644
--- a/tests/ref/overflow_simple_a.html
+++ b/tests/wpt/mozilla/tests/css/overflow_simple_a.html
@@ -1,5 +1,6 @@
 <html>
   <head>
+    <link rel=match href=overflow_simple_b.html>
     <style>
       #first {
       height: 100px;
diff --git a/tests/ref/overflow_simple_b.html b/tests/wpt/mozilla/tests/css/overflow_simple_b.html
similarity index 100%
rename from tests/ref/overflow_simple_b.html
rename to tests/wpt/mozilla/tests/css/overflow_simple_b.html
diff --git a/tests/ref/smiling.png b/tests/wpt/mozilla/tests/css/smiling.png
similarity index 100%
rename from tests/ref/smiling.png
rename to tests/wpt/mozilla/tests/css/smiling.png