Test buffer size greater than DEFAULT_BUFFER_SIZE

Author: marcelm

Lib/test/test_io/test_memoryio.py

@@ -613,6 +613,12 @@ def test_peek(self):
             memio.seek(len(buf))
             self.assertEqual(memio.peek(), self.EOF)
 
+        # Length greater than DEFAULT_BUFFER_SIZE
+        buf = self.buftype("1234567890" * io.DEFAULT_BUFFER_SIZE)
+        with self.ioclass(buf) as memio:
+            self.assertEqual(len(memio.peek()), len(buf))
+            self.assertEqual(len(memio.peek(io.DEFAULT_BUFFER_SIZE + 100)), io.DEFAULT_BUFFER_SIZE + 100)
+
         # Current position beyond buffer end
         with self.ioclass(buf) as memio:
             memio.seek(len(buf) + 100)