---
 src/lxml/tests/test_etree.py |    2 ++
 1 file changed, 2 insertions(+)

--- a/src/lxml/tests/test_etree.py
+++ b/src/lxml/tests/test_etree.py
@@ -5278,6 +5278,8 @@ class ETreeWriteTestCase(HelperTestCase)
         tree = self.parse(_bytes('<a>'+'<b/>'*200+'</a>'))
         with tmpfile() as filename:
             tree.write(filename, compression=9)
+            os.fsync(filename[0])
+            os.lseek(filename[0], 0, os.SEEK_SET)
             data = etree.tostring(etree.parse(filename))
         self.assertEqual(_bytes('<a>'+'<b/>'*200+'</a>'),
                           data)