uasyncio.core: Add test for cancel(coro) function.

Author: pfalcon

uasyncio.core/test_cancel.py

@@ -0,0 +1,73 @@
+import time
+try:
+    import uasyncio.core as asyncio
+    is_uasyncio = True
+except ImportError:
+    import asyncio
+    is_uasyncio = False
+import logging
+#logging.basicConfig(level=logging.DEBUG)
+#asyncio.set_debug(True)
+
+
+output = []
+cancelled = False
+
+def print1(msg):
+    print(msg)
+    output.append(msg)
+
+def looper1(iters):
+    global cancelled
+    try:
+        for i in range(iters):
+            print1("ping1")
+            # sleep() isn't properly cancellable
+            #yield from asyncio.sleep(1.0)
+            t = time.time()
+            while time.time() - t < 1:
+                yield from asyncio.sleep(0)
+        return 10
+    except asyncio.CancelledError:
+        print1("cancelled")
+        cancelled = True
+
+def looper2(iters):
+    for i in range(iters):
+        print1("ping2")
+        # sleep() isn't properly cancellable
+        #yield from asyncio.sleep(1.0)
+        t = time.time()
+        while time.time() - t < 1:
+            yield from asyncio.sleep(0)
+    return 10
+
+
+def run_to():
+    coro = looper1(10)
+    task = loop.create_task(coro)
+    yield from asyncio.sleep(3)
+    if is_uasyncio:
+        asyncio.cancel(coro)
+    else:
+        task.cancel()
+    # Need another eventloop iteration for cancellation to be actually
+    # processed and to see side effects of the cancellation.
+    yield from asyncio.sleep(0)
+    assert cancelled
+
+    coro = looper2(10)
+    task = loop.create_task(coro)
+    yield from asyncio.sleep(2)
+    if is_uasyncio:
+        asyncio.cancel(coro)
+    else:
+        task.cancel()
+    yield from asyncio.sleep(0)
+
+    # Once saw 3 ping3's output on CPython 3.5.2
+    assert output == ['ping1', 'ping1', 'ping1', 'cancelled', 'ping2', 'ping2']
+
+
+loop = asyncio.get_event_loop()
+loop.run_until_complete(run_to())