1 files changed, 40 insertions, 0 deletions
diff --git a/tests/extmod/uasyncio_event_fair.py b/tests/extmod/uasyncio_event_fair.py
new file mode 100644
index 0000000000..37eca5faef
--- /dev/null
+++ b/tests/extmod/uasyncio_event_fair.py
@@ -0,0 +1,40 @@
+# Test fairness of Event.set()
+# That tasks which continuously wait on events don't take over the scheduler
+
+try:
+    import uasyncio as asyncio
+except ImportError:
+    try:
+        import asyncio
+    except ImportError:
+        print("SKIP")
+        raise SystemExit
+
+
+async def task1(id):
+    for i in range(4):
+        print("sleep", id)
+        await asyncio.sleep(0)
+
+
+async def task2(id, ev):
+    for i in range(4):
+        ev.set()
+        ev.clear()
+        print("wait", id)
+        await ev.wait()
+
+
+async def main():
+    ev = asyncio.Event()
+    tasks = [
+        asyncio.create_task(task1(0)),
+        asyncio.create_task(task2(2, ev)),
+        asyncio.create_task(task1(1)),
+        asyncio.create_task(task2(3, ev)),
+    ]
+    await tasks[1]
+    ev.set()
+
+
+asyncio.run(main())