Issue #15487: Add a __sizeof__ implementation for buffered I/O objects.

Patch by Serhiy Storchaka.

1 files changed, 17 insertions, 3 deletions

diff --git a/Lib/test/test_io.py b/Lib/test/test_io.py
index ed8564c..5735350 100644
--- a/Lib/test/test_io.py
+++ b/Lib/test/test_io.py
@@ -802,6 +802,20 @@ class CommonBufferedTests:
             buf.raw = x
 
 
+class SizeofTest:
+
+    @support.cpython_only
+    def test_sizeof(self):
+        bufsize1 = 4096
+        bufsize2 = 8192
+        rawio = self.MockRawIO()
+        bufio = self.tp(rawio, buffer_size=bufsize1)
+        size = sys.getsizeof(bufio) - bufsize1
+        rawio = self.MockRawIO()
+        bufio = self.tp(rawio, buffer_size=bufsize2)
+        self.assertEqual(sys.getsizeof(bufio), size + bufsize2)
+
+
 class BufferedReaderTest(unittest.TestCase, CommonBufferedTests):
     read_mode = "rb"
 
@@ -999,7 +1013,7 @@ class BufferedReaderTest(unittest.TestCase, CommonBufferedTests):
                              "failed for {}: {} != 0".format(n, rawio._extraneous_reads))
 
 
-class CBufferedReaderTest(BufferedReaderTest):
+class CBufferedReaderTest(BufferedReaderTest, SizeofTest):
     tp = io.BufferedReader
 
     def test_constructor(self):
@@ -1260,7 +1274,7 @@ class BufferedWriterTest(unittest.TestCase, CommonBufferedTests):
             self.tp(self.MockRawIO(), 8, 12)
 
 
-class CBufferedWriterTest(BufferedWriterTest):
+class CBufferedWriterTest(BufferedWriterTest, SizeofTest):
     tp = io.BufferedWriter
 
     def test_constructor(self):
@@ -1650,7 +1664,7 @@ class BufferedRandomTest(BufferedReaderTest, BufferedWriterTest):
     # You can't construct a BufferedRandom over a non-seekable stream.
     test_unseekable = None
 
-class CBufferedRandomTest(BufferedRandomTest):
+class CBufferedRandomTest(BufferedRandomTest, SizeofTest):
     tp = io.BufferedRandom
 
     def test_constructor(self):