Fix a bug

eventlet/coros.py

@@ -295,6 +295,7 @@ class CoroutinePool(pools.Pool):
                     if self._next_event is None:
                         self._tracked_events.append(result)
                     else:
+                        
                         ne = self._next_event
                         self._next_event = None
                         ne.send(result)
@@ -375,12 +376,17 @@ class CoroutinePool(pools.Pool):
         """
         assert self._tracked_events is not None, (
             "Must pass track_events=True to the constructor to use CoroutinePool.wait()")
-        if self._next_event is None:
+        if self._next_event is not None:
+            return self._next_event.wait()
+
+        if not self._tracked_events:
+            self._next_event = event()
+            return self._next_event.wait()
+
         result = self._tracked_events.pop(0)
         if not self._tracked_events:
             self._next_event = event()
         return result
-        return self._next_event.wait()
 
     def killall(self):
         for g in self._greenlets:

eventlet/coros_test.py

@@ -212,10 +212,16 @@ class TestCoroutinePool(tests.TestCase):
         pool = coros.CoroutinePool(track_events=True)
         for x in range(6):
             pool.execute(lambda n: n, x)
-        t = api.exc_after(10, RuntimeError)
         for y in range(6):
             pool.wait()
-        t.cancel()
+
+    def test_track_slow_event(self):
+        pool = coros.CoroutinePool(track_events=True)
+        def slow():
+            api.sleep(0.1)
+            return 'ok'
+        pool.execute(slow)
+        self.assertEquals(pool.wait(), 'ok')
 
 
 class IncrActor(coros.Actor):