Closes #12291 for 3.3 - merged fix from 3.2.

1 files changed, 24 insertions, 0 deletions

diff --git a/Lib/test/test_marshal.py b/Lib/test/test_marshal.py
index 8a5590a..dec8129 100644
--- a/Lib/test/test_marshal.py
+++ b/Lib/test/test_marshal.py
@@ -228,6 +228,30 @@ class BugsTestCase(unittest.TestCase):
         invalid_string = b'l\x02\x00\x00\x00\x00\x00\x00\x00'
         self.assertRaises(ValueError, marshal.loads, invalid_string)
 
+    def test_multiple_dumps_and_loads(self):
+        # Issue 12291: marshal.load() should be callable multiple times
+        # with interleaved data written by non-marshal code
+        # Adapted from a patch by Engelbert Gruber.
+        data = (1, 'abc', b'def', 1.0, (2, 'a', ['b', b'c']))
+        for interleaved in (b'', b'0123'):
+            ilen = len(interleaved)
+            positions = []
+            try:
+                with open(support.TESTFN, 'wb') as f:
+                    for d in data:
+                        marshal.dump(d, f)
+                        if ilen:
+                            f.write(interleaved)
+                        positions.append(f.tell())
+                with open(support.TESTFN, 'rb') as f:
+                    for i, d in enumerate(data):
+                        self.assertEqual(d, marshal.load(f))
+                        if ilen:
+                            f.read(ilen)
+                        self.assertEqual(positions[i], f.tell())
+            finally:
+                support.unlink(support.TESTFN)
+
 
 def test_main():
     support.run_unittest(IntTestCase,