fix tests by using a tempfile instead of BytesIO

scrapy/tests/test_pipeline_images.py

@@ -1,9 +1,8 @@
 import os
 import hashlib
 import warnings
-from tempfile import mkdtemp
+from tempfile import mkdtemp, TemporaryFile
 from shutil import rmtree
-from io import BytesIO
 
 from twisted.trial import unittest
 
@@ -201,7 +200,7 @@ class ImagesPipelineTestCaseFields(unittest.TestCase):
 
 
 def _create_image(format, *a, **kw):
-    buf = BytesIO()
+    buf = TemporaryFile()
     Image.new(*a, **kw).save(buf, format)
     buf.seek(0)
     return Image.open(buf)

scrapy/utils/iterators.py

@@ -81,7 +81,7 @@ def _body_or_str(obj, unicode=True):
             return obj.body_as_unicode()
         else:
             return obj.body.decode('utf-8')
-    elif type(obj) is six.text_type:
+    elif isinstance(obj, six.text_type):
         return obj if unicode else obj.encode('utf-8')
     else:
         return obj.decode('utf-8') if unicode else obj