test_map_buffersize_on_infinite_iterable: fetch the first 4 elements

Author: ebonnal

Lib/test/test_concurrent_futures/executor.py

@@ -108,6 +108,9 @@ def test_map_buffersize_on_multiple_iterables(self):
     def test_map_buffersize_on_infinite_iterable(self):
         res = self.executor.map(str, itertools.count(), buffersize=2)
         self.assertEqual(next(res, None), "0")
+        self.assertEqual(next(res, None), "1")
+        self.assertEqual(next(res, None), "2")
+        self.assertEqual(next(res, None), "3")
 
     def test_map_buffersize_on_empty_iterable(self):
         res = self.executor.map(str, [], buffersize=2)