1 files changed, 32 insertions, 0 deletions
diff --git a/testing/web-platform/tests/html/semantics/document-metadata/the-base-element/base-data.html b/testing/web-platform/tests/html/semantics/document-metadata/the-base-element/base-data.html
new file mode 100644
index 0000000000..4905dd84ca
--- /dev/null
+++ b/testing/web-platform/tests/html/semantics/document-metadata/the-base-element/base-data.html
@@ -0,0 +1,32 @@
+<!-- Please update base-javascript.html together with this -->
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>&lt;base> and data: URLs</title>
+<script src=/resources/testharness.js></script>
+<script src=/resources/testharnessreport.js></script>
+<base href="data:/,test">
+<base href="https://example.com/">
+<div id=log></div>
+<script>
+test(() => {
+  const link = document.createElement("a");
+  link.href = "blah";
+  assert_equals(link.href, new URL("blah", document.URL).href);
+}, "First <base> has a data: URL so fallback is used");
+
+test(() => {
+  document.querySelector("base").remove();
+  const link = document.createElement("a");
+  link.href = "blah";
+  assert_equals(link.href, new URL("blah", "https://example.com/").href);
+}, "First <base> is removed so second is used");
+
+test(() => {
+  const base = document.createElement("base");
+  base.href = "data:/,more-test";
+  document.head.prepend(base);
+  const link = document.createElement("a");
+  link.href = "blah";
+  assert_equals(link.href, new URL("blah", document.URL).href);
+}, "Dynamically inserted first <base> has a data: URL so fallback is used");
+</script>