1 files changed, 34 insertions, 0 deletions
diff --git a/testing/web-platform/tests/html/infrastructure/urls/base-url/document-base-uri-synthetic-document.html b/testing/web-platform/tests/html/infrastructure/urls/base-url/document-base-uri-synthetic-document.html
new file mode 100644
index 0000000000..bed090aac4
--- /dev/null
+++ b/testing/web-platform/tests/html/infrastructure/urls/base-url/document-base-uri-synthetic-document.html
@@ -0,0 +1,34 @@
+<!DOCTYPE html>
+<link rel=author href="mailto:jarhar@chromium.org">
+<link rel=help href="https://bugs.chromium.org/p/chromium/issues/detail?id=1486750">
+<link rel=help href="https://html.spec.whatwg.org/multipage/urls-and-fetching.html#document-base-url">
+<link rel=help href="https://html.spec.whatwg.org/multipage/urls-and-fetching.html#fallback-base-url">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<body>
+<script>
+test(() => {
+  const doc1 = document.implementation.createHTMLDocument();
+  assert_equals(doc1.baseURI, 'about:blank', 'document.implementation.createHTMLDocument()');
+
+  const doc2 = document.implementation.createDocument('', '');
+  assert_equals(doc2.baseURI, 'about:blank', 'document.implementation.createDocument("", "")');
+
+  const doc3 = new Document();
+  assert_equals(doc3.baseURI, 'about:blank', 'new Document()');
+}, 'Synthetic documents should return about:blank for document.baseURI.');
+
+test(() => {
+  const doc = document.implementation.createHTMLDocument();
+  assert_equals(doc.baseURI, 'about:blank', 'baseURI should be about:blank without a <base>.');
+
+  const base = doc.createElement('base');
+  base.href = '/foo';
+  doc.head.appendChild(base);
+  assert_equals(doc.baseURI, 'about:blank', '<base> with relative URL should not change the about:blank baseURI.');
+
+  base.href = 'http://example.com/';
+  assert_equals(doc.baseURI, 'http://example.com/', '<base> with complete URL should replace the about:blank baseURI.');
+}, 'Synthetic documents should incorporate <base> href URLs correctly.');
+</script>