Drop python2 support

tests/fields/test_binary_field.py

@@ -123,10 +123,7 @@ class TestBinaryField(MongoDBTestCase):
             upsert=True, new=True, set__bin_field=BIN_VALUE
         )
         assert doc.some_field == "test"
-        if six.PY3:
-            assert doc.bin_field == BIN_VALUE
-        else:
-            assert doc.bin_field == Binary(BIN_VALUE)
+        assert doc.bin_field == BIN_VALUE
 
     def test_update_one(self):
         """Ensures no regression of bug #1127"""
@@ -144,7 +141,4 @@ class TestBinaryField(MongoDBTestCase):
         )
         assert n_updated == 1
         fetched = MyDocument.objects.with_id(doc.id)
-        if six.PY3:
-            assert fetched.bin_field == BIN_VALUE
-        else:
-            assert fetched.bin_field == Binary(BIN_VALUE)
+        assert fetched.bin_field == BIN_VALUE

tests/fields/test_embedded_document_field.py

@@ -1,6 +1,4 @@
 # -*- coding: utf-8 -*-
-from builtins import str
-
 import pytest
 
 from mongoengine import (

tests/fields/test_file_field.py

@@ -3,6 +3,7 @@ import copy
 import os
 import tempfile
 import unittest
+from io import BytesIO
 
 import gridfs
 import pytest
@@ -10,7 +11,6 @@ import six
 
 from mongoengine import *
 from mongoengine.connection import get_db
-from mongoengine.python_support import StringIO
 
 try:
     from PIL import Image
@@ -30,7 +30,7 @@ TEST_IMAGE2_PATH = os.path.join(os.path.dirname(__file__), "mongodb_leaf.png")
 def get_file(path):
     """Use a BytesIO instead of a file to allow
     to have a one-liner and avoid that the file remains opened"""
-    bytes_io = StringIO()
+    bytes_io = BytesIO()
     with open(path, "rb") as f:
         bytes_io.write(f.read())
     bytes_io.seek(0)
@@ -80,7 +80,7 @@ class TestFileField(MongoDBTestCase):
         PutFile.drop_collection()
 
         putfile = PutFile()
-        putstring = StringIO()
+        putstring = BytesIO()
         putstring.write(text)
         putstring.seek(0)
         putfile.the_file.put(putstring, content_type=content_type)

tests/fields/test_url_field.py

@@ -1,6 +1,4 @@
 # -*- coding: utf-8 -*-
-from builtins import str
-
 import pytest
 
 from mongoengine import *