1 files changed, 26 insertions, 0 deletions
diff --git a/testing/web-platform/tests/webvtt/api/VTTRegion/regionAnchorX.html b/testing/web-platform/tests/webvtt/api/VTTRegion/regionAnchorX.html
new file mode 100644
index 0000000000..f7663366cb
--- /dev/null
+++ b/testing/web-platform/tests/webvtt/api/VTTRegion/regionAnchorX.html
@@ -0,0 +1,26 @@
+<!doctype html>
+<title>VTTRegion.regionAnchorX</title>
+<link rel="help" href="https://w3c.github.io/webvtt/#dom-vttregion-regionanchorx">
+<script src=/resources/testharness.js></script>
+<script src=/resources/testharnessreport.js></script>
+<div id=log></div>
+<script>
+test(function() {
+    var region = new VTTRegion();
+    assert_true('regionAnchorX' in region, 'regionAnchorX is not supported');
+
+    for (var i = 0; i <= 100; i++) {
+        region.regionAnchorX = i;
+        assert_equals(region.regionAnchorX, i);
+    }
+
+    region.regionAnchorX = 1.5;
+    assert_equals(region.regionAnchorX, 1.5);
+
+    [-1, -100, -150, 101, 200, 250].forEach(function (invalid) {
+        assert_throws_dom('IndexSizeError', function() {
+            region.regionAnchorX = invalid;
+        });
+    });
+}, document.title + ' script-created region');
+</script>