Preserve the invariant tostring(elem) == b''.join(tostringlist(elem)) and add a test to make sure it keeps working
diff --git a/Lib/test/test_xml_etree.py b/Lib/test/test_xml_etree.py
index d90f978..da1ad09 100644
--- a/Lib/test/test_xml_etree.py
+++ b/Lib/test/test_xml_etree.py
@@ -2286,6 +2286,15 @@
'''<?xml version='1.0' encoding='utf-16'?>\n'''
'''<site />'''.encode("utf-16"))
+ def test_tostringlist_invariant(self):
+ root = ET.fromstring('<tag>foo</tag>')
+ self.assertEqual(
+ ET.tostring(root, 'unicode'),
+ ''.join(ET.tostringlist(root, 'unicode')))
+ self.assertEqual(
+ ET.tostring(root, 'utf-16'),
+ b''.join(ET.tostringlist(root, 'utf-16')))
+
class ParseErrorTest(unittest.TestCase):
def test_subclass(self):
diff --git a/Lib/xml/etree/ElementTree.py b/Lib/xml/etree/ElementTree.py
index 10bf849..3981659 100644
--- a/Lib/xml/etree/ElementTree.py
+++ b/Lib/xml/etree/ElementTree.py
@@ -1190,9 +1190,15 @@
def writable(self):
return True
+ def seekable(self):
+ return True
+
def write(self, b):
data.append(b)
+ def tell(self):
+ return len(data)
+
ElementTree(element).write(DataStream(), encoding, method=method)
return data