--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/third_party/libuv/test/test-thread-equal.c	Wed Jan 14 19:39:52 2026 -0800
@@ -0,0 +1,51 @@
+/* Copyright Joyent, Inc. and other Node contributors. All rights reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include "uv.h"
+#include "task.h"
+
+uv_thread_t main_thread_id;
+uv_thread_t subthreads[2];
+
+static void check_thread(void* arg) {
+  uv_thread_t *thread_id = arg;
+  uv_thread_t self_id = uv_thread_self();
+#ifdef _WIN32
+  ASSERT_NOT_NULL(self_id);
+#endif
+  ASSERT_OK(uv_thread_equal(&main_thread_id, &self_id));
+  *thread_id = uv_thread_self();
+}
+
+TEST_IMPL(thread_equal) {
+  uv_thread_t threads[2];
+  main_thread_id = uv_thread_self();
+#ifdef _WIN32
+  ASSERT_NOT_NULL(main_thread_id);
+#endif
+  ASSERT_NE(0, uv_thread_equal(&main_thread_id, &main_thread_id));
+  ASSERT_OK(uv_thread_create(threads + 0, check_thread, subthreads + 0));
+  ASSERT_OK(uv_thread_create(threads + 1, check_thread, subthreads + 1));
+  ASSERT_OK(uv_thread_join(threads + 0));
+  ASSERT_OK(uv_thread_join(threads + 1));
+  ASSERT_OK(uv_thread_equal(subthreads + 0, subthreads + 1));
+  return 0;
+}