--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/third_party/libuv/test/test-run-once.c	Wed Jan 14 19:39:52 2026 -0800
@@ -0,0 +1,48 @@
+/* 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"
+
+#define NUM_TICKS 64
+
+static uv_idle_t idle_handle;
+static int idle_counter;
+
+
+static void idle_cb(uv_idle_t* handle) {
+  ASSERT_PTR_EQ(handle, &idle_handle);
+
+  if (++idle_counter == NUM_TICKS)
+    uv_idle_stop(handle);
+}
+
+
+TEST_IMPL(run_once) {
+  uv_idle_init(uv_default_loop(), &idle_handle);
+  uv_idle_start(&idle_handle, idle_cb);
+
+  while (uv_run(uv_default_loop(), UV_RUN_ONCE));
+  ASSERT_EQ(idle_counter, NUM_TICKS);
+
+  MAKE_VALGRIND_HAPPY(uv_default_loop());
+  return 0;
+}