diff --git a/components/layout_2020/flow/mod.rs b/components/layout_2020/flow/mod.rs
index 22c23253be4..cb88ecebe6a 100644
--- a/components/layout_2020/flow/mod.rs
+++ b/components/layout_2020/flow/mod.rs
@@ -482,7 +482,7 @@ fn layout_in_flow_non_replaced_block_level(
     let end_margin_can_collapse_with_children = block_is_same_formatting_context &&
         pbm.padding.block_end == Length::zero() &&
         pbm.border.block_end == Length::zero() &&
-        block_size == LengthOrAuto::Auto &&
+        block_size.auto_is(|| Length::zero()) == Length::zero() &&
         min_box_size.block == Length::zero();
 
     let mut clearance = Length::zero();
diff --git a/tests/wpt/metadata-layout-2020/css/CSS2/margin-padding-clear/margin-collapse-016.xht.ini b/tests/wpt/metadata-layout-2020/css/CSS2/margin-padding-clear/margin-collapse-016.xht.ini
deleted file mode 100644
index 6b4b4a53ff0..00000000000
--- a/tests/wpt/metadata-layout-2020/css/CSS2/margin-padding-clear/margin-collapse-016.xht.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[margin-collapse-016.xht]
-  expected: FAIL
diff --git a/tests/wpt/metadata-layout-2020/css/CSS2/margin-padding-clear/margin-collapse-019.xht.ini b/tests/wpt/metadata-layout-2020/css/CSS2/margin-padding-clear/margin-collapse-019.xht.ini
deleted file mode 100644
index 90e327ac0d9..00000000000
--- a/tests/wpt/metadata-layout-2020/css/CSS2/margin-padding-clear/margin-collapse-019.xht.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[margin-collapse-019.xht]
-  expected: FAIL
diff --git a/tests/wpt/metadata-layout-2020/css/CSS2/normal-flow/margin-collapse-through-zero-height-block.html.ini b/tests/wpt/metadata-layout-2020/css/CSS2/normal-flow/margin-collapse-through-zero-height-block.html.ini
deleted file mode 100644
index 48d090f286b..00000000000
--- a/tests/wpt/metadata-layout-2020/css/CSS2/normal-flow/margin-collapse-through-zero-height-block.html.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[margin-collapse-through-zero-height-block.html]
-  expected: FAIL