link_future() only accepts coroutine objects, not coroutine functions

3 files changed, 19 insertions, 2 deletions

diff --git a/aiogreen.py b/aiogreen.py
index f1ec37c..45b4ac4 100644
--- a/aiogreen.py
+++ b/aiogreen.py
@@ -301,7 +301,7 @@ def wrap_greenthread(gt, loop=None):
 
 
 def link_future(future, loop=None):
-    """Wait for a future, a task, or a coroutine from a greenthread.
+    """Wait for a future, a task, or a coroutine object from a greenthread.
 
     Return the result or raise the exception of the future.
 
diff --git a/doc/using.rst b/doc/using.rst
index 5fcf043..0956085 100644
--- a/doc/using.rst
+++ b/doc/using.rst
@@ -115,7 +115,7 @@ link_future
 
 .. function:: link_future(future, loop=None)
 
-   Wait for a future, a task, or a coroutine from a greenthread.
+   Wait for a future, a task, or a coroutine object from a greenthread.
 
    Return the result or raise the exception of the future.
 
diff --git a/tests/test_eventlet.py b/tests/test_eventlet.py
index 2361e81..4a8970c 100644
--- a/tests/test_eventlet.py
+++ b/tests/test_eventlet.py
@@ -234,6 +234,23 @@ class LinkFutureTests(tests.TestCase):
         self.loop.run_forever()
         self.assertEqual(result, ['error'])
 
+    def test_link_future_invalid_type(self):
+        def func(obj):
+            return aiogreen.link_future(obj)
+
+        @asyncio.coroutine
+        def coro_func():
+            print("do something")
+
+        def regular_func():
+            return 3
+
+        for obj in (coro_func, regular_func):
+            gt = eventlet.spawn(func, coro_func)
+            # ignore logged traceback
+            with tests.mock.patch('traceback.print_exception') as m_print:
+                self.assertRaises(TypeError, gt.wait)
+
     def test_link_future_wrong_loop(self):
         result = []
         loop2 = asyncio.new_event_loop()