Add tests for _chain_future (threough _wrap_future)

Author: 1st1

tests/test_futures.py

@@ -317,12 +317,43 @@ def test_future_exception_never_retrieved(self):
     def test_future_exception_never_retrieved_debug(self):
         self.check_future_exception_never_retrieved(True)
 
-    def test_future_set_result_unless_cancelled(self):
-        from asyncio import futures
-        fut = self.create_future()
-        fut.cancel()
-        futures._set_result_unless_cancelled(fut, 2)
-        self.assertTrue(fut.cancelled())
+    def test_future_wrap_future(self):
+        from uvloop.loop import _wrap_future
+        def run(arg):
+            return (arg, threading.get_ident())
+        ex = concurrent.futures.ThreadPoolExecutor(1)
+        f1 = ex.submit(run, 'oi')
+        f2 = _wrap_future(f1, loop=self.loop)
+        res, ident = self.loop.run_until_complete(f2)
+        self.assertIsInstance(f2, asyncio.Future)
+        self.assertEqual(res, 'oi')
+        self.assertNotEqual(ident, threading.get_ident())
+
+    def test_future_wrap_future_future(self):
+        from uvloop.loop import _wrap_future
+        f1 = self.create_future()
+        f2 = _wrap_future(f1)
+        self.assertIs(f1, f2)
+
+    def test_future_wrap_future_cancel(self):
+        from uvloop.loop import _wrap_future
+        f1 = concurrent.futures.Future()
+        f2 = _wrap_future(f1, loop=self.loop)
+        f2.cancel()
+        test_utils.run_briefly(self.loop)
+        self.assertTrue(f1.cancelled())
+        self.assertTrue(f2.cancelled())
+
+    def test_future_wrap_future_cancel2(self):
+        from uvloop.loop import _wrap_future
+        f1 = concurrent.futures.Future()
+        f2 = _wrap_future(f1, loop=self.loop)
+        f1.set_result(42)
+        f2.cancel()
+        test_utils.run_briefly(self.loop)
+        self.assertFalse(f1.cancelled())
+        self.assertEqual(f1.result(), 42)
+        self.assertTrue(f2.cancelled())
 
 
 class _TestFuturesDoneCallbacks:

uvloop/chain_futs.pyx

@@ -1,4 +1,5 @@
-# Copied from asyncio 3.5.2
+# Copied from asyncio 3.5.2.  Remove this file when we don't need
+# to support earlier versions.
 
 cdef _set_concurrent_future_state(concurrent, source):
     """Copy state from a future to a concurrent.futures.Future."""
@@ -86,3 +87,23 @@ cdef _chain_future(source, destination):
 
     destination.add_done_callback(_call_check_cancel)
     source.add_done_callback(_call_set_state)
+
+
+def _wrap_future(future, *, loop=None):
+    # Don't use this function -- it's here for tests purposes only
+    # and can be removed in future versions of uvloop.
+
+    if isinstance(future, aio_Future):
+        return future
+    assert isinstance(future, cc_Future), \
+        'concurrent.futures.Future is expected, got {!r}'.format(future)
+    if loop is None:
+        loop = aio_get_event_loop()
+    try:
+        create_future = loop.create_future
+    except AttributeError:
+        new_future = aio_Future(loop=loop)
+    else:
+        new_future = create_future()
+    _chain_future(future, new_future)
+    return new_future