Add tests for the writelines() method of file objects.
Original patch by Felipe Cruz.
diff --git a/Lib/test/test_fileio.py b/Lib/test/test_fileio.py
index c6863d6..71ec44c 100644
--- a/Lib/test/test_fileio.py
+++ b/Lib/test/test_fileio.py
@@ -9,6 +9,7 @@
 from array import array
 from weakref import proxy
 from functools import wraps
+from UserList import UserList
 
 from test.test_support import TESTFN, check_warnings, run_unittest, make_bad_fd
 from test.test_support import py3k_bytes as bytes
@@ -71,6 +72,26 @@
         n = self.f.readinto(a)
         self.assertEqual(array(b'b', [1, 2]), a[:n])
 
+    def testWritelinesList(self):
+        l = [b'123', b'456']
+        self.f.writelines(l)
+        self.f.close()
+        self.f = _FileIO(TESTFN, 'rb')
+        buf = self.f.read()
+        self.assertEqual(buf, b'123456')
+
+    def testWritelinesUserList(self):
+        l = UserList([b'123', b'456'])
+        self.f.writelines(l)
+        self.f.close()
+        self.f = _FileIO(TESTFN, 'rb')
+        buf = self.f.read()
+        self.assertEqual(buf, b'123456')
+
+    def testWritelinesError(self):
+        self.assertRaises(TypeError, self.f.writelines, [1, 2, 3])
+        self.assertRaises(TypeError, self.f.writelines, None)
+
     def test_none_args(self):
         self.f.write(b"hi\nbye\nabc")
         self.f.close()