diff --git a/testing/web-platform/tests/mathml/relations/css-styling/padding-border-margin/border-001.html b/testing/web-platform/tests/mathml/relations/css-styling/padding-border-margin/border-001.html
index 83eb924d82389..784491cf2e1bf 100644
--- a/testing/web-platform/tests/mathml/relations/css-styling/padding-border-margin/border-001.html
+++ b/testing/web-platform/tests/mathml/relations/css-styling/padding-border-margin/border-001.html
@@ -8,7 +8,7 @@
 <script src="/resources/testharness.js"></script>
 <script src="/resources/testharnessreport.js"></script>
 <script src="/mathml/support/feature-detection.js"></script>
-<script src="helper.js"></script>
+<script src="/mathml/support/box-comparison.js"></script>
 <script>
   var epsilon = 1;
 
diff --git a/testing/web-platform/tests/mathml/relations/css-styling/padding-border-margin/border-002.html b/testing/web-platform/tests/mathml/relations/css-styling/padding-border-margin/border-002.html
index cbf3efe096697..85a3dc2e2ac57 100644
--- a/testing/web-platform/tests/mathml/relations/css-styling/padding-border-margin/border-002.html
+++ b/testing/web-platform/tests/mathml/relations/css-styling/padding-border-margin/border-002.html
@@ -8,7 +8,7 @@
 <script src="/resources/testharness.js"></script>
 <script src="/resources/testharnessreport.js"></script>
 <script src="/mathml/support/mathml-fragments.js"></script>
-<script src="helper.js"></script>
+<script src="/mathml/support/box-comparison.js"></script>
 <script>
   var epsilon = 1;
 
diff --git a/testing/web-platform/tests/mathml/relations/css-styling/padding-border-margin/margin-001.html b/testing/web-platform/tests/mathml/relations/css-styling/padding-border-margin/margin-001.html
index c674d4c829e41..67146882319b4 100644
--- a/testing/web-platform/tests/mathml/relations/css-styling/padding-border-margin/margin-001.html
+++ b/testing/web-platform/tests/mathml/relations/css-styling/padding-border-margin/margin-001.html
@@ -8,7 +8,7 @@
 <script src="/resources/testharness.js"></script>
 <script src="/resources/testharnessreport.js"></script>
 <script src="/mathml/support/feature-detection.js"></script>
-<script src="helper.js"></script>
+<script src="/mathml/support/box-comparison.js"></script>
 <script>
   var epsilon = 1;
 
diff --git a/testing/web-platform/tests/mathml/relations/css-styling/padding-border-margin/margin-002.html b/testing/web-platform/tests/mathml/relations/css-styling/padding-border-margin/margin-002.html
index 10b66a3114e50..87583b584a34f 100644
--- a/testing/web-platform/tests/mathml/relations/css-styling/padding-border-margin/margin-002.html
+++ b/testing/web-platform/tests/mathml/relations/css-styling/padding-border-margin/margin-002.html
@@ -8,7 +8,7 @@
 <script src="/resources/testharness.js"></script>
 <script src="/resources/testharnessreport.js"></script>
 <script src="/mathml/support/mathml-fragments.js"></script>
-<script src="helper.js"></script>
+<script src="/mathml/support/box-comparison.js"></script>
 <script>
   var epsilon = 1;
 
diff --git a/testing/web-platform/tests/mathml/relations/css-styling/padding-border-margin/padding-001.html b/testing/web-platform/tests/mathml/relations/css-styling/padding-border-margin/padding-001.html
index f195d4794030d..afcd930452655 100644
--- a/testing/web-platform/tests/mathml/relations/css-styling/padding-border-margin/padding-001.html
+++ b/testing/web-platform/tests/mathml/relations/css-styling/padding-border-margin/padding-001.html
@@ -8,7 +8,7 @@
 <script src="/resources/testharness.js"></script>
 <script src="/resources/testharnessreport.js"></script>
 <script src="/mathml/support/feature-detection.js"></script>
-<script src="helper.js"></script>
+<script src="/mathml/support/box-comparison.js"></script>
 <script>
   var epsilon = 1;
 
diff --git a/testing/web-platform/tests/mathml/relations/css-styling/padding-border-margin/padding-002.html b/testing/web-platform/tests/mathml/relations/css-styling/padding-border-margin/padding-002.html
index 073faa1aeb3e7..c634e4076e066 100644
--- a/testing/web-platform/tests/mathml/relations/css-styling/padding-border-margin/padding-002.html
+++ b/testing/web-platform/tests/mathml/relations/css-styling/padding-border-margin/padding-002.html
@@ -8,7 +8,7 @@
 <script src="/resources/testharness.js"></script>
 <script src="/resources/testharnessreport.js"></script>
 <script src="/mathml/support/mathml-fragments.js"></script>
-<script src="helper.js"></script>
+<script src="/mathml/support/box-comparison.js"></script>
 <script>
   var epsilon = 1;
 
diff --git a/testing/web-platform/tests/mathml/relations/css-styling/width-height-001.html b/testing/web-platform/tests/mathml/relations/css-styling/width-height-001.html
new file mode 100644
index 0000000000000..8d52f48a2d95a
--- /dev/null
+++ b/testing/web-platform/tests/mathml/relations/css-styling/width-height-001.html
@@ -0,0 +1,50 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8">
+<title>width, height, inline-size and block-size</title>
+<link rel="help" href="https://mathml-refresh.github.io/mathml-core/#layout-algorithms">
+<meta name="assert" content="Verify that width, height, inline-size and block-size properties are ignored.">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/mathml/support/mathml-fragments.js"></script>
+<script src="/mathml/support/box-comparison.js"></script>
+<script>
+  var epsilon = 1;
+
+  setup({ explicit_done: true });
+  window.addEventListener("load", runTests);
+
+  function runTests() {
+
+    for (tag in MathMLFragments) {
+        if (!FragmentHelper.isValidChildOfMrow(tag) || tag === "mtable")
+            continue;
+
+        test(function() {
+            var style = "width: 500px; height: 400px;";
+            var s = compareSizeWithAndWithoutStyle(tag, style);
+            assert_approx_equals(s.width_delta, 0, epsilon, "width");
+            assert_approx_equals(s.height_delta, 0, epsilon, "height");
+            assert_approx_equals(s.element_width_delta, 0, epsilon, "element width");
+            assert_approx_equals(s.element_height_delta, 0, epsilon, "element height");
+        }, `width and height properties on ${tag}`);
+
+        test(function() {
+            var style = "inline-size: 500px; block-size: 400px;";
+            var s = compareSizeWithAndWithoutStyle(tag, style);
+            assert_approx_equals(s.width_delta, 0, epsilon, "width");
+            assert_approx_equals(s.height_delta, 0, epsilon, "height");
+            assert_approx_equals(s.element_width_delta, 0, epsilon, "element width");
+            assert_approx_equals(s.element_height_delta, 0, epsilon, "element height");
+        }, `inline-size and block-size properties on ${tag}`);
+    }
+
+    done();
+  }
+</script>
+</head>
+<body>
+  <div id="log"></div>
+</body>
+</html>
diff --git a/testing/web-platform/tests/mathml/relations/css-styling/padding-border-margin/helper.js b/testing/web-platform/tests/mathml/support/box-comparison.js
similarity index 100%
rename from testing/web-platform/tests/mathml/relations/css-styling/padding-border-margin/helper.js
rename to testing/web-platform/tests/mathml/support/box-comparison.js