1 files changed, 38 insertions, 0 deletions
diff --git a/testing/web-platform/tests/html/semantics/forms/the-input-element/input-disabled-fieldset-dynamic.html b/testing/web-platform/tests/html/semantics/forms/the-input-element/input-disabled-fieldset-dynamic.html
new file mode 100644
index 0000000000..eefcd972bf
--- /dev/null
+++ b/testing/web-platform/tests/html/semantics/forms/the-input-element/input-disabled-fieldset-dynamic.html
@@ -0,0 +1,38 @@
+<!doctype html>
+<meta charset="utf-8">
+<link rel="help" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1861027">
+<script src=/resources/testharness.js></script>
+<script src=/resources/testharnessreport.js></script>
+<script src=/resources/testdriver.js></script>
+<script src=/resources/testdriver-actions.js></script>
+<script src=/resources/testdriver-vendor.js></script>
+<fieldset id="fieldset" disabled>
+  <input id="target">
+</fieldset>
+<script>
+const target = document.getElementById("target");
+const fieldset = document.getElementById("fieldset");
+promise_test(async function() {
+  await new Promise(r => window.addEventListener("load", r, { once: true }));
+  assert_true(target.matches(":disabled"), "Fieldset disables the input");
+  assert_true(target.matches(":read-only"), "Disabled implies read-only");
+
+  // Try to focus, it shouldn't be focusable.
+  target.focus();
+
+  assert_not_equals(document.activeElement, target, "Should not be focusable");
+
+  fieldset.removeAttribute("disabled");
+
+  assert_false(target.matches(":disabled"), "Should go back to writable");
+  assert_false(target.matches(":read-only"), "No longer read-only");
+
+  // Should be focusable now.
+  target.focus();
+
+  assert_equals(document.activeElement, target, "Should not be focusable");
+
+  await test_driver.send_keys(target, "A");
+  assert_equals(target.value, "A", "Typing should work");
+});
+</script>