Plug another leak, and finally add a test for #1174606 (read() from /dev/zero).

The leak was the reason my previous attempts at testing failed...

1 files changed, 16 insertions, 0 deletions

diff --git a/Lib/test/test_io.py b/Lib/test/test_io.py
index 1b80add..d5be405 100644
--- a/Lib/test/test_io.py
+++ b/Lib/test/test_io.py
@@ -505,6 +505,22 @@ class IOTest(unittest.TestCase):
         with open(support.TESTFN, "rb") as f:
             self.assertEqual(f.read(), b"abcxxx")
 
+    def test_unbounded_file(self):
+        # Issue #1174606: reading from an unbounded stream such as /dev/zero.
+        zero = "/dev/zero"
+        if not os.path.exists(zero):
+            raise unittest.SkipTest("{0} does not exist".format(zero))
+        if sys.maxsize > 0x7FFFFFFF:
+            raise unittest.SkipTest("test can only run in a 32-bit address space")
+        if support.real_max_memuse < support._2G:
+            raise unittest.SkipTest("test requires at least 2GB of memory")
+        with open(zero, "rb", buffering=0) as f:
+            self.assertRaises(OverflowError, f.read)
+        with open(zero, "rb") as f:
+            self.assertRaises(OverflowError, f.read)
+        with open(zero, "r") as f:
+            self.assertRaises(OverflowError, f.read)
+
 class CIOTest(IOTest):
     pass