diff --git a/.travis.yml b/.travis.yml
index 77e49547..ebef0578 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -5,8 +5,6 @@ python:
   - "3.6"
 matrix:
   fast_finish: true
-  allow_failures:
-    - python: "3.6"
 install:
   - "pip install ."
   - if [[ $TRAVIS_PYTHON_VERSION == 2.6 ]]; then pip install unittest2; fi
diff --git a/gestionatr/cli.py b/gestionatr/cli.py
index 3a25a6ad..dc339961 100644
--- a/gestionatr/cli.py
+++ b/gestionatr/cli.py
@@ -1,4 +1,6 @@
 # -*- encoding: utf-8 -*-
+from __future__ import absolute_import, unicode_literals
+import six
 import sys
 import click
 
@@ -29,24 +31,24 @@ def atr():
 @click.option("--filename", "-f", help="path to XML filename", required=True)
 @click.option("--sector", "-s", help="e (power) or g (gas)", default="e")
 def test(filename, sector):
-    with open(filename, 'r') as xml_file:
+    with open(filename, 'rb') as xml_file:
         try:
             data = xml_file.read()
-            if sector == u'e':
+            if sector == 'e':
                 m = message.Message(data)
-            elif sector == u'g':
+            elif sector == 'g':
                 m = message_gas.MessageGas(data)
             m.parse_xml()
-            sys.stdout.write(u'Correct File\n')
+            sys.stdout.write('Correct File\n')
         except except_f1 as e:
-            error_txt = unicode(e.value).encode(errors='ignore')
+            error_txt = six.text_type(e.value).encode(errors='ignore')
             sys.stdout.write(
-                u'WARNING: Invalid File: {0}\n'.format(error_txt)
+                'WARNING: Invalid File: {0}\n'.format(error_txt)
             )
         except Exception as e:
-            error_txt = unicode(e).encode(errors='ignore')
+            error_txt = six.text_type(e).encode(errors='ignore')
             sys.stdout.write(
-                u'WARNING: Invalid File: {0}\n'.format(error_txt)
+                'WARNING: Invalid File: {0}\n'.format(error_txt)
             )
         finally:
             sys.stdout.flush()
diff --git a/gestionatr/defs.py b/gestionatr/defs.py
index b0c104a0..0386dc6b 100644
--- a/gestionatr/defs.py
+++ b/gestionatr/defs.py
@@ -1,4 +1,5 @@
 # -*- coding: utf-8 -*-
+from __future__ import absolute_import, unicode_literals
 
 # Mapeig de distribuïdores
 provincies_arago = ['22', '44', '50']  # Osca, Terol, Saragossa
diff --git a/gestionatr/defs_gas.py b/gestionatr/defs_gas.py
index 727dbbfe..f140b134 100644
--- a/gestionatr/defs_gas.py
+++ b/gestionatr/defs_gas.py
@@ -1,5 +1,6 @@
 # -*- coding: utf-8 -*-
-from defs import SUBTYPES_R101
+from __future__ import absolute_import, unicode_literals
+from .defs import SUBTYPES_R101
 
 TAULA_CATEGORIA_SUJETO = [
     ('COM', 'Comercializadora'),
diff --git a/gestionatr/helpers/__init__.py b/gestionatr/helpers/__init__.py
index 8cf31568..e63aac48 100644
--- a/gestionatr/helpers/__init__.py
+++ b/gestionatr/helpers/__init__.py
@@ -1,2 +1,3 @@
 # -*- coding: utf-8 -*-
-from funcions import *
+from __future__ import absolute_import
+from .funcions import *
diff --git a/gestionatr/helpers/funcions.py b/gestionatr/helpers/funcions.py
index 59b3fbc9..8f8304e5 100644
--- a/gestionatr/helpers/funcions.py
+++ b/gestionatr/helpers/funcions.py
@@ -3,6 +3,8 @@
 """Helper functions for libComXml
 """
 
+from __future__ import absolute_import, unicode_literals
+
 CODIS_REFACT = {'RT42011': '40',
                 'RT12012': '41',
                 'RM42012': '42'}
diff --git a/gestionatr/input/messages/A1.py b/gestionatr/input/messages/A1.py
index 0b6c013c..5595efd4 100644
--- a/gestionatr/input/messages/A1.py
+++ b/gestionatr/input/messages/A1.py
@@ -1,8 +1,9 @@
 # -*- coding: utf-8 -*-
-from message import Message
-from Deadlines import ProcessDeadline
+from __future__ import absolute_import, unicode_literals
+from .message import Message
+from .Deadlines import ProcessDeadline
 from gestionatr.input.messages import except_f1
-from D1 import DatosInstGen, DatosSuministro, Autoconsumo
+from .D1 import DatosInstGen, DatosSuministro, Autoconsumo
 from gestionatr.utils import get_rec_attr
 
 
diff --git a/gestionatr/input/messages/A12_26.py b/gestionatr/input/messages/A12_26.py
index 76cac467..396634b9 100644
--- a/gestionatr/input/messages/A12_26.py
+++ b/gestionatr/input/messages/A12_26.py
@@ -1,8 +1,9 @@
 # -*- coding: utf-8 -*-
-from message_gas import MessageGas
-from Deadlines import ProcessDeadline, DeadLine, Workdays, Naturaldays
+from __future__ import absolute_import, unicode_literals
+from .message_gas import MessageGas
+from .Deadlines import ProcessDeadline, DeadLine, Workdays, Naturaldays
 from gestionatr.utils import get_rec_attr
-from A1_46 import *
+from .A1_46 import *
 
 
 class A12_26(A1_46):
diff --git a/gestionatr/input/messages/A19_45.py b/gestionatr/input/messages/A19_45.py
index a3aa0c48..787e7d0d 100644
--- a/gestionatr/input/messages/A19_45.py
+++ b/gestionatr/input/messages/A19_45.py
@@ -1,8 +1,9 @@
 # -*- coding: utf-8 -*-
-from message_gas import MessageGas
-from Deadlines import ProcessDeadline, DeadLine, Workdays, Naturaldays
+from __future__ import absolute_import, unicode_literals
+from .message_gas import MessageGas
+from .Deadlines import ProcessDeadline, DeadLine, Workdays, Naturaldays
 from gestionatr.utils import get_rec_attr
-from A12_26 import *
+from .A12_26 import *
 
 
 class A19_45(A12_26):
diff --git a/gestionatr/input/messages/A1_02.py b/gestionatr/input/messages/A1_02.py
index ad1e75a3..cb363093 100644
--- a/gestionatr/input/messages/A1_02.py
+++ b/gestionatr/input/messages/A1_02.py
@@ -1,5 +1,6 @@
 # -*- coding: utf-8 -*-
-from A1_41 import *
+from __future__ import absolute_import, unicode_literals
+from .A1_41 import *
 from gestionatr.utils import get_rec_attr
 
 
diff --git a/gestionatr/input/messages/A1_03.py b/gestionatr/input/messages/A1_03.py
index b9215364..220076d9 100644
--- a/gestionatr/input/messages/A1_03.py
+++ b/gestionatr/input/messages/A1_03.py
@@ -1,5 +1,6 @@
 # -*- coding: utf-8 -*-
-from A1_44 import *
+from __future__ import absolute_import, unicode_literals
+from .A1_44 import *
 
 
 class A1_03(A1_44):
diff --git a/gestionatr/input/messages/A1_04.py b/gestionatr/input/messages/A1_04.py
index 4cefad3c..99c397d5 100644
--- a/gestionatr/input/messages/A1_04.py
+++ b/gestionatr/input/messages/A1_04.py
@@ -1,6 +1,7 @@
 # -*- coding: utf-8 -*-
+from __future__ import absolute_import, unicode_literals
 from gestionatr.utils import get_rec_attr
-from A1_44 import A1_44
+from .A1_44 import A1_44
 
 
 class A1_04(A1_44):
diff --git a/gestionatr/input/messages/A1_05.py b/gestionatr/input/messages/A1_05.py
index b4cd22e0..403e8d9b 100644
--- a/gestionatr/input/messages/A1_05.py
+++ b/gestionatr/input/messages/A1_05.py
@@ -1,5 +1,6 @@
 # -*- coding: utf-8 -*-
-from A1_02 import *
+from __future__ import absolute_import, unicode_literals
+from .A1_02 import *
 from gestionatr.utils import get_rec_attr
 
 
diff --git a/gestionatr/input/messages/A1_41.py b/gestionatr/input/messages/A1_41.py
index 12ee7f7b..537c3cc7 100644
--- a/gestionatr/input/messages/A1_41.py
+++ b/gestionatr/input/messages/A1_41.py
@@ -1,6 +1,7 @@
 # -*- coding: utf-8 -*-
-from message_gas import MessageGas
-from Deadlines import ProcessDeadline, DeadLine, Workdays, Naturaldays
+from __future__ import absolute_import, unicode_literals
+from .message_gas import MessageGas
+from .Deadlines import ProcessDeadline, DeadLine, Workdays, Naturaldays
 from gestionatr.utils import get_rec_attr
 
 
diff --git a/gestionatr/input/messages/A1_44.py b/gestionatr/input/messages/A1_44.py
index 53c38e19..125b4f7d 100644
--- a/gestionatr/input/messages/A1_44.py
+++ b/gestionatr/input/messages/A1_44.py
@@ -1,8 +1,9 @@
 # -*- coding: utf-8 -*-
-from message_gas import MessageGas
-from Deadlines import ProcessDeadline, DeadLine, Workdays, Naturaldays
+from __future__ import absolute_import, unicode_literals
+from .message_gas import MessageGas
+from .Deadlines import ProcessDeadline, DeadLine, Workdays, Naturaldays
 from gestionatr.utils import get_rec_attr
-from A1_05 import *
+from .A1_05 import *
 
 
 class A1_44(A1_05):
diff --git a/gestionatr/input/messages/A1_46.py b/gestionatr/input/messages/A1_46.py
index 99550f46..a0b79e44 100644
--- a/gestionatr/input/messages/A1_46.py
+++ b/gestionatr/input/messages/A1_46.py
@@ -1,8 +1,9 @@
 # -*- coding: utf-8 -*-
-from message_gas import MessageGas
-from Deadlines import ProcessDeadline, DeadLine, Workdays, Naturaldays
+from __future__ import absolute_import, unicode_literals
+from .message_gas import MessageGas
+from .Deadlines import ProcessDeadline, DeadLine, Workdays, Naturaldays
 from gestionatr.utils import get_rec_attr
-from A1_48 import *
+from .A1_48 import *
 
 
 class A1_46(A1_48):
diff --git a/gestionatr/input/messages/A1_48.py b/gestionatr/input/messages/A1_48.py
index 09ede64c..45a9982f 100644
--- a/gestionatr/input/messages/A1_48.py
+++ b/gestionatr/input/messages/A1_48.py
@@ -1,8 +1,9 @@
 # -*- coding: utf-8 -*-
-from message_gas import MessageGas
-from Deadlines import ProcessDeadline, DeadLine, Workdays, Naturaldays
+from __future__ import absolute_import, unicode_literals
+from .message_gas import MessageGas
+from .Deadlines import ProcessDeadline, DeadLine, Workdays, Naturaldays
 from gestionatr.utils import get_rec_attr
-from A1_04 import *
+from .A1_04 import *
 from gestionatr.defs_gas import SUBTYPES_A1_48
 
 
diff --git a/gestionatr/input/messages/A3.py b/gestionatr/input/messages/A3.py
index 4fb6ca31..e03cc91d 100644
--- a/gestionatr/input/messages/A3.py
+++ b/gestionatr/input/messages/A3.py
@@ -1,6 +1,7 @@
 # -*- coding: utf-8 -*-
-from C2 import C2
-from Deadlines import DeadLine, Workdays, Naturaldays
+from __future__ import absolute_import, unicode_literals
+from .C2 import C2
+from .Deadlines import DeadLine, Workdays, Naturaldays
 from gestionatr.utils import get_rec_attr
 
 
diff --git a/gestionatr/input/messages/B1.py b/gestionatr/input/messages/B1.py
index f5f51f25..b9889e60 100644
--- a/gestionatr/input/messages/B1.py
+++ b/gestionatr/input/messages/B1.py
@@ -1,8 +1,8 @@
 # -*- coding: utf-8 -*-
-
-from C2 import C2, DatosSolicitud, Contacto
-from C1 import DatosAceptacion
-from Deadlines import ProcessDeadline, DeadLine, Workdays, Naturaldays
+from __future__ import absolute_import, unicode_literals
+from .C2 import C2, DatosSolicitud, Contacto
+from .C1 import DatosAceptacion
+from .Deadlines import ProcessDeadline, DeadLine, Workdays, Naturaldays
 from gestionatr.utils import get_rec_attr
 
 
diff --git a/gestionatr/input/messages/B70.py b/gestionatr/input/messages/B70.py
index 963b6761..99f83427 100644
--- a/gestionatr/input/messages/B70.py
+++ b/gestionatr/input/messages/B70.py
@@ -1,5 +1,6 @@
 # -*- coding: utf-8 -*-
-from message_gas import MessageGas
+from __future__ import absolute_import, unicode_literals
+from .message_gas import MessageGas
 from gestionatr.utils import get_rec_attr
 from gestionatr.defs_gas import TIPUS_CONCEPTES
 from datetime import datetime
diff --git a/gestionatr/input/messages/C1.py b/gestionatr/input/messages/C1.py
index f7935f60..bc7a72b0 100644
--- a/gestionatr/input/messages/C1.py
+++ b/gestionatr/input/messages/C1.py
@@ -1,6 +1,7 @@
 # -*- coding: utf-8 -*-
-from message import Message
-from Deadlines import ProcessDeadline, DeadLine, Workdays, Naturaldays
+from __future__ import absolute_import, unicode_literals
+from .message import Message
+from .Deadlines import ProcessDeadline, DeadLine, Workdays, Naturaldays
 from gestionatr.utils import get_rec_attr
 
 
diff --git a/gestionatr/input/messages/C2.py b/gestionatr/input/messages/C2.py
index 592f9f7e..8d27caa9 100644
--- a/gestionatr/input/messages/C2.py
+++ b/gestionatr/input/messages/C2.py
@@ -1,6 +1,7 @@
 # -*- coding: utf-8 -*-
-from C1 import C1, DatosSolicitud, Contrato, Cliente
-from Deadlines import DeadLine, Workdays, Naturaldays
+from __future__ import absolute_import, unicode_literals
+from .C1 import C1, DatosSolicitud, Contrato, Cliente
+from .Deadlines import DeadLine, Workdays, Naturaldays
 from gestionatr.utils import get_rec_attr
 
 
diff --git a/gestionatr/input/messages/D1.py b/gestionatr/input/messages/D1.py
index 5a061a75..b7e460a1 100644
--- a/gestionatr/input/messages/D1.py
+++ b/gestionatr/input/messages/D1.py
@@ -1,4 +1,5 @@
 # -*- coding: utf-8 -*-
+from __future__ import absolute_import, unicode_literals
 from gestionatr.input.messages import C1
 from gestionatr.utils import get_rec_attr
 
diff --git a/gestionatr/input/messages/Deadlines.py b/gestionatr/input/messages/Deadlines.py
index 5f09c4f5..75818cbc 100644
--- a/gestionatr/input/messages/Deadlines.py
+++ b/gestionatr/input/messages/Deadlines.py
@@ -1,3 +1,4 @@
+from __future__ import absolute_import, unicode_literals
 from collections import namedtuple
 from datetime import datetime, timedelta
 from workdays import workday
diff --git a/gestionatr/input/messages/F1.py b/gestionatr/input/messages/F1.py
index 7b377e17..6cfa7ecd 100644
--- a/gestionatr/input/messages/F1.py
+++ b/gestionatr/input/messages/F1.py
@@ -1,9 +1,11 @@
 # -*- coding: utf-8 -*-
-from message import Message
+from __future__ import absolute_import, unicode_literals
+from .message import Message
 from gestionatr.input.messages.C2 import Direccion
 from gestionatr.defs import TARIFES_SEMPRE_MAX
 from datetime import datetime, date
 from gestionatr.utils import repartir_consums_entre_lectures
+import six
 
 # Magnituds d'OCSUM
 MAGNITUDS_OCSUM = {
@@ -1272,7 +1274,7 @@ def get_comptadors(self):
 
             di, df = aparell_multi.get_dates_inici_i_final()
             comptadors.append((di, df, aparell_multi))
-        return [a[2] for a in sorted(comptadors, lambda x,y: cmp(x[0], y[0]))]
+        return [a[2] for a in sorted(comptadors, key=lambda x: x[0])]
 
     def get_info_potencia(self):
         """Retorna els periodes de potència"""
diff --git a/gestionatr/input/messages/M1.py b/gestionatr/input/messages/M1.py
index c06c17a3..53ee63a8 100644
--- a/gestionatr/input/messages/M1.py
+++ b/gestionatr/input/messages/M1.py
@@ -1,7 +1,7 @@
 # -*- coding: utf-8 -*-
-
-from C2 import C2, DatosSolicitud
-from Deadlines import ProcessDeadline, DeadLine, Workdays, Naturaldays
+from __future__ import absolute_import, unicode_literals
+from .C2 import C2, DatosSolicitud
+from .Deadlines import ProcessDeadline, DeadLine, Workdays, Naturaldays
 from gestionatr.utils import get_rec_attr
 
 
diff --git a/gestionatr/input/messages/Q1.py b/gestionatr/input/messages/Q1.py
index 9eec5b27..d096d7d8 100644
--- a/gestionatr/input/messages/Q1.py
+++ b/gestionatr/input/messages/Q1.py
@@ -1,7 +1,8 @@
 # -*- coding: utf-8 -*-
-from message import Message
+from __future__ import absolute_import, unicode_literals
+from .message import Message
 from gestionatr.utils import get_rec_attr
-from Deadlines import ProcessDeadline
+from .Deadlines import ProcessDeadline
 
 
 class Q1(Message, ProcessDeadline):
diff --git a/gestionatr/input/messages/R1.py b/gestionatr/input/messages/R1.py
index 2a8f5141..25b8bf2b 100644
--- a/gestionatr/input/messages/R1.py
+++ b/gestionatr/input/messages/R1.py
@@ -1,8 +1,9 @@
 # -*- coding: utf-8 -*-
-from C2 import C2, Cliente, Contacto
-from C1 import DatosAceptacion
-from W1 import LecturaAportada
-from Deadlines import DeadLine, Workdays, Naturaldays
+from __future__ import absolute_import, unicode_literals
+from .C2 import C2, Cliente, Contacto
+from .C1 import DatosAceptacion
+from .W1 import LecturaAportada
+from .Deadlines import DeadLine, Workdays, Naturaldays
 from gestionatr.utils import get_rec_attr
 from gestionatr.defs import SUBTYPES_R101
 
diff --git a/gestionatr/input/messages/W1.py b/gestionatr/input/messages/W1.py
index de6a5519..282f3764 100644
--- a/gestionatr/input/messages/W1.py
+++ b/gestionatr/input/messages/W1.py
@@ -1,7 +1,8 @@
 # -*- coding: utf-8 -*-
+from __future__ import absolute_import, unicode_literals
 from gestionatr.utils import get_rec_attr
-from C1 import C1
-from Deadlines import ProcessDeadline, DeadLine, Workdays, Naturaldays
+from .C1 import C1
+from .Deadlines import ProcessDeadline, DeadLine, Workdays, Naturaldays
 
 
 class W1(C1):
diff --git a/gestionatr/input/messages/__init__.py b/gestionatr/input/messages/__init__.py
index 31a4b343..51928b36 100644
--- a/gestionatr/input/messages/__init__.py
+++ b/gestionatr/input/messages/__init__.py
@@ -1,25 +1,26 @@
 # -*- coding: utf-8 -*-
-from message import Message, except_f1
-from C1 import C1
-from C2 import C2
-from A1 import A1
-from A3 import A3
-from B1 import B1
-from M1 import M1
-from D1 import D1
-from W1 import W1
-from Q1 import Q1
-from R1 import R1
-from F1 import F1
-from message_gas import MessageGas
-from A1_41 import A1_41
-from B70 import B7031, B7032, B70
-from A1_02 import A1_02
-from A1_05 import A1_05
-from A1_44 import A1_44
-from A1_03 import A1_03
-from A1_04 import A1_04
-from A1_48 import A1_48
-from A1_46 import A1_46
-from A12_26 import A12_26
-from A19_45 import A19_45
+from __future__ import absolute_import
+from .message import Message, except_f1
+from .C1 import C1
+from .C2 import C2
+from .A1 import A1
+from .A3 import A3
+from .B1 import B1
+from .M1 import M1
+from .D1 import D1
+from .W1 import W1
+from .Q1 import Q1
+from .R1 import R1
+from .F1 import F1
+from .message_gas import MessageGas
+from .A1_41 import A1_41
+from .B70 import B7031, B7032, B70
+from .A1_02 import A1_02
+from .A1_05 import A1_05
+from .A1_44 import A1_44
+from .A1_03 import A1_03
+from .A1_04 import A1_04
+from .A1_48 import A1_48
+from .A1_46 import A1_46
+from .A12_26 import A12_26
+from .A19_45 import A19_45
diff --git a/gestionatr/input/messages/defs.py b/gestionatr/input/messages/defs.py
index d5b6040a..d9f1c793 100644
--- a/gestionatr/input/messages/defs.py
+++ b/gestionatr/input/messages/defs.py
@@ -1,5 +1,5 @@
 # -*- coding: utf-8 -*-
-
+from __future__ import absolute_import, unicode_literals
 # Definició de variables de llibreria
 # Taula 107 del document d'OCSUM:
 # OCSUM - E - Tablas de códigos 2012.05.23.doc
diff --git a/gestionatr/input/messages/message.py b/gestionatr/input/messages/message.py
index 12dc4d1a..5ccccdba 100644
--- a/gestionatr/input/messages/message.py
+++ b/gestionatr/input/messages/message.py
@@ -1,6 +1,9 @@
 # -*- coding: utf-8 -*-
+from __future__ import absolute_import, unicode_literals
+from io import IOBase
 from lxml import objectify, etree
 from gestionatr import utils
+import six
 
 XSD_DATA = {'F1': {'01': 'Facturacion.xsd'},
             'Q1': {'01': 'SaldoLecturasFacturacion.xsd'},
@@ -121,7 +124,7 @@ def __init__(self, xml, force_tipus=None):
         """Construir mensaje base."""
         self.obj = None
         self.error = None
-        if isinstance(xml, file):
+        if (six.PY2 and isinstance(xml, file)) or isinstance(xml, IOBase):
             self.check_fpos(xml)
             xml = xml.read()
         self.xml_orig = xml
@@ -146,7 +149,7 @@ def __init__(self, xml, force_tipus=None):
     @staticmethod
     def check_fpos(f_obj):
         """Setejar la posició actual dels fixers"""
-        if isinstance(f_obj, file) and f_obj.tell() != 0:
+        if isinstance(f_obj, IOBase) and f_obj.tell() != 0:
             f_obj.seek(0)
 
     def set_tipus(self):
@@ -226,9 +229,8 @@ def set_xsd(self):
                 self._header = MAIN_MESSAGE_XSD[fitxer.split(".xsd")[0]]
             except:
                 self._header = fitxer.split(".xsd")[0]
-            xsd = utils.get_data(fitxer)
-            self.f_xsd = open(xsd, 'r')
-        except except_f1, e:
+            self.xsd = utils.get_data(fitxer)
+        except except_f1 as e:
             raise e
         except:
             msg = u"Fichero '{0}' corrupto".format(
@@ -242,18 +244,20 @@ def get_pas_xml(self):
 
     def parse_xml(self, validate=True):
         """Importar contenido del xml"""
-        self.check_fpos(self.f_xsd)
-        schema = etree.XMLSchema(file=self.f_xsd)
-        parser = objectify.makeparser(schema=schema)
-        try:
-            self.obj = objectify.fromstring(self.str_xml, parser)
-        except Exception as e:
-            self.error = e.message
-            if validate:
-                raise except_f1('Error', u'Documento inválido: {0}'.format(e))
-            else:
-                parser = objectify.makeparser(schema=None)
+        with open(self.xsd, 'rb') as f_xsd:
+            self.f_xsd = f_xsd
+            self.check_fpos(self.f_xsd)
+            schema = etree.XMLSchema(file=self.f_xsd)
+            parser = objectify.makeparser(schema=schema)
+            try:
                 self.obj = objectify.fromstring(self.str_xml, parser)
+            except Exception as e:
+                self.error = e.message
+                if validate:
+                    raise except_f1('Error', u'Documento inválido: {0}'.format(e))
+                else:
+                    parser = objectify.makeparser(schema=None)
+                    self.obj = objectify.fromstring(self.str_xml, parser)
 
     # Funcions relacionades amb la capçalera del XML
     @property
diff --git a/gestionatr/input/messages/message_gas.py b/gestionatr/input/messages/message_gas.py
index 369a4cd2..273eacfa 100644
--- a/gestionatr/input/messages/message_gas.py
+++ b/gestionatr/input/messages/message_gas.py
@@ -1,7 +1,8 @@
 # -*- coding: utf-8 -*-
+from __future__ import absolute_import, unicode_literals
 from lxml import objectify, etree
 from gestionatr import utils
-from message import XSD_DATA, MAIN_MESSAGE_XSD, Message, except_f1
+from .message import XSD_DATA, MAIN_MESSAGE_XSD, Message, except_f1
 from gestionatr.utils import get_rec_attr
 
 XSD_DATA.update({
diff --git a/gestionatr/output/messages/base.py b/gestionatr/output/messages/base.py
index 6777931b..60a52a03 100644
--- a/gestionatr/output/messages/base.py
+++ b/gestionatr/output/messages/base.py
@@ -3,8 +3,9 @@
 # pylint: disable=E1002
 # pylint: disable=E1101
 # pylint: disable=C0111
-
+from __future__ import absolute_import, unicode_literals
 from libcomxml.core import XmlModel, XmlField
+import six
 
 
 class Cabecera(XmlModel):
@@ -127,4 +128,4 @@ def rep_ruedas(n_rodes):
 
 def rep_cut(length):
     # if empty return text to avoid False
-    return lambda text: text and unicode(text)[:length].strip() or text
+    return lambda text: text and six.text_type(text)[:length].strip() or text
diff --git a/gestionatr/output/messages/base_gas.py b/gestionatr/output/messages/base_gas.py
index 96200817..77254acf 100644
--- a/gestionatr/output/messages/base_gas.py
+++ b/gestionatr/output/messages/base_gas.py
@@ -1,4 +1,5 @@
 # -*- coding: utf-8 -*-
+from __future__ import absolute_import, unicode_literals
 from libcomxml.core import XmlModel, XmlField
 
 
diff --git a/gestionatr/output/messages/sw_a1.py b/gestionatr/output/messages/sw_a1.py
index 296e4e93..87158d20 100644
--- a/gestionatr/output/messages/sw_a1.py
+++ b/gestionatr/output/messages/sw_a1.py
@@ -1,4 +1,5 @@
 # -*- coding: utf-8 -*-
+from __future__ import absolute_import, unicode_literals
 from libcomxml.core import XmlModel, XmlField
 
 from gestionatr.output.messages.sw_d1 import Autoconsumo, DatosSuministro, DatosInstGen
diff --git a/gestionatr/output/messages/sw_a1_02.py b/gestionatr/output/messages/sw_a1_02.py
index 613a387e..26415ac8 100644
--- a/gestionatr/output/messages/sw_a1_02.py
+++ b/gestionatr/output/messages/sw_a1_02.py
@@ -1,5 +1,5 @@
 # -*- coding: utf-8 -*-
-
+from __future__ import absolute_import, unicode_literals
 from libcomxml.core import XmlModel, XmlField
 from gestionatr.output.messages.base_gas import Heading
 
diff --git a/gestionatr/output/messages/sw_a1_03.py b/gestionatr/output/messages/sw_a1_03.py
index d0866616..b886153d 100644
--- a/gestionatr/output/messages/sw_a1_03.py
+++ b/gestionatr/output/messages/sw_a1_03.py
@@ -1,5 +1,5 @@
 # -*- coding: utf-8 -*-
-
+from __future__ import absolute_import, unicode_literals
 from libcomxml.core import XmlModel, XmlField
 from gestionatr.output.messages.base_gas import Heading
 
diff --git a/gestionatr/output/messages/sw_a1_04.py b/gestionatr/output/messages/sw_a1_04.py
index 04614745..c5759628 100644
--- a/gestionatr/output/messages/sw_a1_04.py
+++ b/gestionatr/output/messages/sw_a1_04.py
@@ -1,5 +1,5 @@
 # -*- coding: utf-8 -*-
-
+from __future__ import absolute_import, unicode_literals
 from libcomxml.core import XmlModel, XmlField
 from gestionatr.output.messages.base_gas import Heading
 from gestionatr.output.messages.sw_a1_41 import Registerdoclist, Registerdoc
diff --git a/gestionatr/output/messages/sw_a1_05.py b/gestionatr/output/messages/sw_a1_05.py
index 478b97df..d0cbc39f 100644
--- a/gestionatr/output/messages/sw_a1_05.py
+++ b/gestionatr/output/messages/sw_a1_05.py
@@ -1,5 +1,5 @@
 # -*- coding: utf-8 -*-
-
+from __future__ import absolute_import, unicode_literals
 from libcomxml.core import XmlModel, XmlField
 from gestionatr.output.messages.base_gas import Heading
 from gestionatr.output.messages.sw_a1_41 import Registerdoclist, Registerdoc
diff --git a/gestionatr/output/messages/sw_a1_41.py b/gestionatr/output/messages/sw_a1_41.py
index 0d19df9a..712634d8 100644
--- a/gestionatr/output/messages/sw_a1_41.py
+++ b/gestionatr/output/messages/sw_a1_41.py
@@ -1,5 +1,5 @@
 # -*- coding: utf-8 -*-
-
+from __future__ import absolute_import, unicode_literals
 from libcomxml.core import XmlModel, XmlField
 from gestionatr.output.messages.base_gas import Heading
 
diff --git a/gestionatr/output/messages/sw_a1_44.py b/gestionatr/output/messages/sw_a1_44.py
index e405506f..8d2648aa 100644
--- a/gestionatr/output/messages/sw_a1_44.py
+++ b/gestionatr/output/messages/sw_a1_44.py
@@ -1,5 +1,5 @@
 # -*- coding: utf-8 -*-
-
+from __future__ import absolute_import, unicode_literals
 from libcomxml.core import XmlModel, XmlField
 from gestionatr.output.messages.base_gas import Heading
 from gestionatr.output.messages.sw_a1_05 import Registerdoclist, Registerdoc
diff --git a/gestionatr/output/messages/sw_a1_46.py b/gestionatr/output/messages/sw_a1_46.py
index 6dd80c1e..edd0cd3f 100644
--- a/gestionatr/output/messages/sw_a1_46.py
+++ b/gestionatr/output/messages/sw_a1_46.py
@@ -1,5 +1,5 @@
 # -*- coding: utf-8 -*-
-
+from __future__ import absolute_import, unicode_literals
 from libcomxml.core import XmlModel, XmlField
 from gestionatr.output.messages.base_gas import Heading
 from gestionatr.output.messages.sw_a1_05 import Registerdoclist, Registerdoc
diff --git a/gestionatr/output/messages/sw_a1_48.py b/gestionatr/output/messages/sw_a1_48.py
index e6e08a09..31db6a5a 100644
--- a/gestionatr/output/messages/sw_a1_48.py
+++ b/gestionatr/output/messages/sw_a1_48.py
@@ -1,5 +1,5 @@
 # -*- coding: utf-8 -*-
-
+from __future__ import absolute_import, unicode_literals
 from libcomxml.core import XmlModel, XmlField
 from gestionatr.output.messages.base_gas import Heading
 from gestionatr.output.messages.sw_a1_05 import Registerdoclist, Registerdoc
diff --git a/gestionatr/output/messages/sw_a3.py b/gestionatr/output/messages/sw_a3.py
index 4744a242..ebcdf70f 100644
--- a/gestionatr/output/messages/sw_a3.py
+++ b/gestionatr/output/messages/sw_a3.py
@@ -1,4 +1,5 @@
 # -*- coding: utf-8 -*-
+from __future__ import absolute_import, unicode_literals
 from gestionatr.output.messages.sw_c2 import *
 
 
diff --git a/gestionatr/output/messages/sw_b1.py b/gestionatr/output/messages/sw_b1.py
index 1cebc405..ba983d81 100644
--- a/gestionatr/output/messages/sw_b1.py
+++ b/gestionatr/output/messages/sw_b1.py
@@ -1,4 +1,5 @@
 # -*- coding: utf-8 -*-
+from __future__ import absolute_import, unicode_literals
 from gestionatr.output.messages.sw_c2 import *
 
 
diff --git a/gestionatr/output/messages/sw_c1.py b/gestionatr/output/messages/sw_c1.py
index 1eb59fc9..e50d91f3 100644
--- a/gestionatr/output/messages/sw_c1.py
+++ b/gestionatr/output/messages/sw_c1.py
@@ -1,5 +1,5 @@
 # -*- coding: utf-8 -*-
-
+from __future__ import absolute_import, unicode_literals
 from libcomxml.core import XmlModel, XmlField
 from gestionatr.output.messages.base import Cabecera
 
diff --git a/gestionatr/output/messages/sw_c2.py b/gestionatr/output/messages/sw_c2.py
index df1f150e..82b31d6a 100644
--- a/gestionatr/output/messages/sw_c2.py
+++ b/gestionatr/output/messages/sw_c2.py
@@ -1,4 +1,5 @@
 # -*- coding: utf-8 -*-
+from __future__ import absolute_import, unicode_literals
 from gestionatr.output.messages.sw_c1 import *
 from gestionatr.output.messages.base import rep_cut
 
diff --git a/gestionatr/output/messages/sw_d1.py b/gestionatr/output/messages/sw_d1.py
index fd068b36..04bba17a 100644
--- a/gestionatr/output/messages/sw_d1.py
+++ b/gestionatr/output/messages/sw_d1.py
@@ -1,4 +1,5 @@
 # -*- coding: utf-8 -*-
+from __future__ import absolute_import, unicode_literals
 from libcomxml.core import XmlModel, XmlField
 from gestionatr.output.messages.base import Cabecera
 
diff --git a/gestionatr/output/messages/sw_f1.py b/gestionatr/output/messages/sw_f1.py
index 8915cdab..41d89db2 100644
--- a/gestionatr/output/messages/sw_f1.py
+++ b/gestionatr/output/messages/sw_f1.py
@@ -1,5 +1,5 @@
 # -*- coding: utf-8 -*-
-
+from __future__ import absolute_import, unicode_literals
 from libcomxml.core import XmlModel, XmlField
 from gestionatr.output.messages.base import Cabecera, rep_fecha, \
     rep_fecha_sin_hora, rep_decimal, rep_entera, rep_entera2, rep_ruedas, rep_cut
diff --git a/gestionatr/output/messages/sw_m1.py b/gestionatr/output/messages/sw_m1.py
index 2ae24eb9..5c2fbf75 100644
--- a/gestionatr/output/messages/sw_m1.py
+++ b/gestionatr/output/messages/sw_m1.py
@@ -1,4 +1,5 @@
 # -*- coding: utf-8 -*-
+from __future__ import absolute_import, unicode_literals
 from gestionatr.output.messages.sw_c2 import *
 
 
diff --git a/gestionatr/output/messages/sw_q1.py b/gestionatr/output/messages/sw_q1.py
index 74d7dcd5..6acd6a01 100644
--- a/gestionatr/output/messages/sw_q1.py
+++ b/gestionatr/output/messages/sw_q1.py
@@ -1,5 +1,5 @@
 # -*- coding: utf-8 -*-
-
+from __future__ import absolute_import, unicode_literals
 from libcomxml.core import XmlModel, XmlField
 from gestionatr.output.messages.base import Cabecera
 
diff --git a/gestionatr/output/messages/sw_r1.py b/gestionatr/output/messages/sw_r1.py
index ebfc6904..4e35ece6 100644
--- a/gestionatr/output/messages/sw_r1.py
+++ b/gestionatr/output/messages/sw_r1.py
@@ -1,4 +1,5 @@
 # -*- coding: utf-8 -*-
+from __future__ import absolute_import, unicode_literals
 from gestionatr.output.messages.sw_c2 import *
 from gestionatr.output.messages.base import CabeceraReclamacion
 
diff --git a/gestionatr/output/messages/sw_w1.py b/gestionatr/output/messages/sw_w1.py
index 63652139..8cf4d839 100644
--- a/gestionatr/output/messages/sw_w1.py
+++ b/gestionatr/output/messages/sw_w1.py
@@ -1,4 +1,5 @@
 # -*- coding: utf-8 -*-
+from __future__ import absolute_import, unicode_literals
 from gestionatr.output.messages.sw_c1 import *
 
 
diff --git a/gestionatr/parser_xml_defs_gas.py b/gestionatr/parser_xml_defs_gas.py
index 6f1a5a7f..2bbc5290 100644
--- a/gestionatr/parser_xml_defs_gas.py
+++ b/gestionatr/parser_xml_defs_gas.py
@@ -1,3 +1,4 @@
+from __future__ import absolute_import, unicode_literals
 import click
 from lxml import objectify
 
diff --git a/gestionatr/utils.py b/gestionatr/utils.py
index f7f1cb4c..cba5f07c 100644
--- a/gestionatr/utils.py
+++ b/gestionatr/utils.py
@@ -1,8 +1,12 @@
+from __future__ import absolute_import, unicode_literals
 from gestionatr import defs
 from gestionatr import defs_gas
 import os
 from collections import namedtuple
 from datetime import datetime
+import six
+if six.PY3:
+    from functools import reduce
 
 _ROOT = os.path.abspath(os.path.dirname(__file__))
 
diff --git a/requirements.txt b/requirements.txt
index 385ee1a2..065b31fb 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -2,3 +2,4 @@ lxml
 libcomxml
 workdays
 click
+six
diff --git a/tests/test_cli.py b/tests/test_cli.py
index 27319609..a4e8291d 100644
--- a/tests/test_cli.py
+++ b/tests/test_cli.py
@@ -1,5 +1,6 @@
 #!/usr/bin/env python
 # -*- coding: utf-8 -*-
+from __future__ import absolute_import
 from click.testing import CliRunner
 from .utils import get_data
 from gestionatr.cli import atr, test
@@ -18,7 +19,6 @@ def test_version(self):
 
     def test_atr_test_default_e(self):
         runner = CliRunner()
-
         result = runner.invoke(test, ['-f', get_data('f101_factura_atr.xml')])
         expect(result.output).to(equal('Correct File\n'))
 
diff --git a/tests/test_helpers.py b/tests/test_helpers.py
index c303f96e..bb3ab25f 100644
--- a/tests/test_helpers.py
+++ b/tests/test_helpers.py
@@ -1,5 +1,6 @@
 #!/usr/bin/env python
 # -*- coding: utf-8 -*-
+from __future__ import absolute_import, unicode_literals
 from . import unittest
 from gestionatr.helpers import *
 from .utils import get_data
@@ -30,7 +31,8 @@ def test_parse_totals_refact(self):
 
     def test_validate_xml(self):
         from gestionatr.utils import validate_xml
-        xml_c101_minim = open(get_data("c101_minim.xml"), "r")
-        xml_c101_ok = xml_c101_minim.read()
-        res = validate_xml(xml_c101_ok)
-        self.assertTrue(res.valid)
+        with open(get_data("c101_minim.xml"), "rb") as xml_c101_minim:
+            xml_c101_ok = xml_c101_minim.read()
+            res = validate_xml(xml_c101_ok)
+            self.assertTrue(res.valid)
+
diff --git a/tests/test_input.py b/tests/test_input.py
index 00dfc325..99579e04 100644
--- a/tests/test_input.py
+++ b/tests/test_input.py
@@ -6,12 +6,23 @@
 from gestionatr.input.messages.F1 import agrupar_lectures_per_data, obtenir_data_inici_i_final
 from . import unittest
 from .utils import get_data
+import six
 
+class TestCaseCompat(unittest.TestCase):
 
-class test_MessageBase(unittest.TestCase):
+    def assertItemsEqual(self, first, second, msg=None):
+        if six.PY3:
+            return self.assertCountEqual(first, second, msg)
+        else:
+            return super(TestCaseCompat, self).assertItemsEqual(
+                first, second, msg
+            )
+
+
+class test_MessageBase(TestCaseCompat):
 
     def setUp(self):
-        self.xml_c101_cabecera = open(get_data("c101.xml"), "r")
+        self.xml_c101_cabecera = open(get_data("c101.xml"), "rb")
 
     def tearDown(self):
         self.xml_c101_cabecera.close()
@@ -30,10 +41,10 @@ def test_cabecera_model(self):
         self.assertEqual(c.data_sollicitud, u'2016-07-21 12:59:47')
 
 
-class test_Deadline(unittest.TestCase):
+class test_Deadline(TestCaseCompat):
 
     def setUp(self):
-        self.xml_c101_completo = open(get_data("c101.xml"), "r")
+        self.xml_c101_completo = open(get_data("c101.xml"), "rb")
 
     def test_limit(self):
         c = C1(self.xml_c101_completo)
@@ -45,20 +56,20 @@ def tearDown(self):
         self.xml_c101_completo.close()
 
 
-class test_C1(unittest.TestCase):
+class test_C1(TestCaseCompat):
 
     def setUp(self):
-        self.xml_c101_completo = open(get_data("c101.xml"), "r")
-        self.xml_c101_minim = open(get_data("c101_minim.xml"), "r")
-        self.xml_c102_accept = open(get_data("c102_accept.xml"), "r")
-        self.xml_c102_reject = open(get_data("c102_reject.xml"), "r")
-        self.xml_c104 = open(get_data("c104.xml"), "r")
-        self.xml_c105 = open(get_data("c105.xml"), "r")
-        self.xml_c106 = open(get_data("c106.xml"), "r")
-        self.xml_c108 = open(get_data("c108.xml"), "r")
-        self.xml_c109 = open(get_data("c109.xml"), "r")
-        self.xml_c111 = open(get_data("c111.xml"), "r")
-        self.xml_c112 = open(get_data("c112.xml"), "r")
+        self.xml_c101_completo = open(get_data("c101.xml"), "rb")
+        self.xml_c101_minim = open(get_data("c101_minim.xml"), "rb")
+        self.xml_c102_accept = open(get_data("c102_accept.xml"), "rb")
+        self.xml_c102_reject = open(get_data("c102_reject.xml"), "rb")
+        self.xml_c104 = open(get_data("c104.xml"), "rb")
+        self.xml_c105 = open(get_data("c105.xml"), "rb")
+        self.xml_c106 = open(get_data("c106.xml"), "rb")
+        self.xml_c108 = open(get_data("c108.xml"), "rb")
+        self.xml_c109 = open(get_data("c109.xml"), "rb")
+        self.xml_c111 = open(get_data("c111.xml"), "rb")
+        self.xml_c112 = open(get_data("c112.xml"), "rb")
 
     def tearDown(self):
         self.xml_c101_completo.close()
@@ -343,12 +354,12 @@ def test_c112(self):
         self.assertEqual(c.fecha_rechazo, u'2017-02-02')
 
 
-class test_C2(unittest.TestCase):
+class test_C2(TestCaseCompat):
 
     def setUp(self):
-        self.xml_c201_completo = open(get_data("c201.xml"), "r")
-        self.xml_c202_accept = open(get_data("c202_accept.xml"), "r")
-        self.xml_c203 = open(get_data("c203.xml"), "r")
+        self.xml_c201_completo = open(get_data("c201.xml"), "rb")
+        self.xml_c202_accept = open(get_data("c202_accept.xml"), "rb")
+        self.xml_c203 = open(get_data("c203.xml"), "rb")
 
     def tearDown(self):
         self.xml_c201_completo.close()
@@ -494,12 +505,12 @@ def test_c203(self):
         self.assertEqual(i2.comentarios, u'Com 2')
 
 
-class test_A1(unittest.TestCase):
+class test_A1(TestCaseCompat):
 
     def setUp(self):
-        self.xml_a101 = open(get_data("a101.xml"), "r")
-        self.xml_a102_accept = open(get_data("a102_accept.xml"), "r")
-        self.xml_a102_reject = open(get_data("a102_reject.xml"), "r")
+        self.xml_a101 = open(get_data("a101.xml"), "rb")
+        self.xml_a102_accept = open(get_data("a102_accept.xml"), "rb")
+        self.xml_a102_reject = open(get_data("a102_reject.xml"), "rb")
 
     def tearDown(self):
         self.xml_a101.close()
@@ -626,11 +637,11 @@ def test_a102_reject(self):
 
 
 
-class test_A3(unittest.TestCase):
+class test_A3(TestCaseCompat):
 
     def setUp(self):
-        self.xml_a301 = open(get_data("a301.xml"), "r")
-        self.xml_a301_correos = open(get_data("a301_correos.xml"), "r")
+        self.xml_a301 = open(get_data("a301.xml"), "rb")
+        self.xml_a301_correos = open(get_data("a301_correos.xml"), "rb")
 
     def tearDown(self):
         self.xml_a301.close()
@@ -736,13 +747,13 @@ def test_a301_correos(self):
         self.assertEqual(direccion.apartado_de_correos, u'A1234')
 
 
-class test_B1(unittest.TestCase):
+class test_B1(TestCaseCompat):
 
     def setUp(self):
-        self.xml_b101 = open(get_data("b101.xml"), "r")
-        self.xml_b102_accept = open(get_data("b102_accept.xml"), "r")
-        self.xml_b104_accept = open(get_data("b104_accept.xml"), "r")
-        self.xml_b105 = open(get_data("b105.xml"), "r")
+        self.xml_b101 = open(get_data("b101.xml"), "rb")
+        self.xml_b102_accept = open(get_data("b102_accept.xml"), "rb")
+        self.xml_b104_accept = open(get_data("b104_accept.xml"), "rb")
+        self.xml_b105 = open(get_data("b105.xml"), "rb")
 
     def tearDown(self):
         self.xml_b101.close()
@@ -852,10 +863,10 @@ def test_b105(self):
         self.assertEqual(md2.fecha_lectura_firme, u'2003-01-03')
 
 
-class test_M1(unittest.TestCase):
+class test_M1(TestCaseCompat):
 
     def setUp(self):
-        self.xml_m101 = open(get_data("m101.xml"), "r")
+        self.xml_m101 = open(get_data("m101.xml"), "rb")
 
     def tearDown(self):
         self.xml_m101.close()
@@ -915,14 +926,14 @@ def test_m101(self):
         self.assertFalse(m1.comentarios)
 
 
-class test_D1(unittest.TestCase):
+class test_D1(TestCaseCompat):
 
     def setUp(self):
-        self.xml_d101 = open(get_data("d101.xml"), "r")
-        self.xml_d101_min_with_info = open(get_data("d101_min_with_info.xml"), "r")
-        self.xml_d101_fully_min = open(get_data("d101_fully_min.xml"), "r")
-        self.xml_d102_accept = open(get_data("d102_accept.xml"), "r")
-        self.xml_d102_reject = open(get_data("d102_reject.xml"), "r")
+        self.xml_d101 = open(get_data("d101.xml"), "rb")
+        self.xml_d101_min_with_info = open(get_data("d101_min_with_info.xml"), "rb")
+        self.xml_d101_fully_min = open(get_data("d101_fully_min.xml"), "rb")
+        self.xml_d102_accept = open(get_data("d102_accept.xml"), "rb")
+        self.xml_d102_reject = open(get_data("d102_reject.xml"), "rb")
 
     def tearDown(self):
         self.xml_d101.close()
@@ -1065,12 +1076,12 @@ def test_d102_reject(self):
         self.assertEqual(rej.codigo_motivo, u'F1')
         self.assertEqual(rej.comentarios, u'Motiu de rebuig F1')
 
-class test_W1(unittest.TestCase):
+class test_W1(TestCaseCompat):
 
     def setUp(self):
-        self.xml_w101 = open(get_data("w101.xml"), "r")
-        self.xml_w102_accept = open(get_data("w102_accept.xml"), "r")
-        self.xml_w102_reject = open(get_data("w102_reject.xml"), "r")
+        self.xml_w101 = open(get_data("w101.xml"), "rb")
+        self.xml_w102_accept = open(get_data("w102_accept.xml"), "rb")
+        self.xml_w102_reject = open(get_data("w102_reject.xml"), "rb")
 
     def tearDown(self):
         self.xml_w101.close()
@@ -1116,10 +1127,10 @@ def test_w102_reject(self):
         self.assertEqual(rej1.comentarios,  'Motiu de rebuig 01: No existe Punto de Suministro asociado al CUPS')
 
 
-class test_Q1(unittest.TestCase):
+class test_Q1(TestCaseCompat):
 
     def setUp(self):
-        self.xml_q101 = open(get_data("q101.xml"), "r")
+        self.xml_q101 = open(get_data("q101.xml"), "rb")
 
     def tearDown(self):
         self.xml_q101.close()
@@ -1161,16 +1172,16 @@ def test_q101(self):
         self.assertEqual(anomalia.tipo_anomalia, u'05')
 
 
-class test_R1(unittest.TestCase):
+class test_R1(TestCaseCompat):
 
     def setUp(self):
-        self.xml_r101 = open(get_data("r101.xml"), "r")
-        self.xml_r102_accept = open(get_data("r102_accept.xml"), "r")
-        self.xml_r103 = open(get_data("r103.xml"), "r")
-        self.xml_r103_intervenciones = open(get_data("r103_intervenciones.xml"), "r")
-        self.xml_r103_no_add_info = open(get_data("r103_no_add_info.xml"), "r")
-        self.xml_r104 = open(get_data("r104.xml"), "r")
-        self.xml_r105 = open(get_data("r105.xml"), "r")
+        self.xml_r101 = open(get_data("r101.xml"), "rb")
+        self.xml_r102_accept = open(get_data("r102_accept.xml"), "rb")
+        self.xml_r103 = open(get_data("r103.xml"), "rb")
+        self.xml_r103_intervenciones = open(get_data("r103_intervenciones.xml"), "rb")
+        self.xml_r103_no_add_info = open(get_data("r103_no_add_info.xml"), "rb")
+        self.xml_r104 = open(get_data("r104.xml"), "rb")
+        self.xml_r105 = open(get_data("r105.xml"), "rb")
 
     def tearDown(self):
         self.xml_r101.close()
@@ -1465,27 +1476,27 @@ def test_r105(self):
         self.assertEqual(r1.cod_contrato, u'383922379')
 
 
-class test_F1(unittest.TestCase):
+class test_F1(TestCaseCompat):
     def setUp(self):
-        with open(get_data("f101_factura_atr.xml"), "r") as f:
+        with open(get_data("f101_factura_atr.xml"), "rb") as f:
             self.xml_f101_atr_invoice = f.read()
-        with open(get_data("f101_factura_atr_30A.xml"), "r") as f:
+        with open(get_data("f101_factura_atr_30A.xml"), "rb") as f:
             self.xml_f101_atr_invoice_30A = f.read()
-        with open(get_data("f101_factura_atr_61B_exceso.xml"), "r") as f:
+        with open(get_data("f101_factura_atr_61B_exceso.xml"), "rb") as f:
             self.xml_f101_atr_invoice_61B = f.read()
-        with open(get_data("f101_factura_atr_ajuste.xml"), "r") as f:
+        with open(get_data("f101_factura_atr_ajuste.xml"), "rb") as f:
             self.xml_f101_atr_invoice_ajuste = f.read()
-        with open(get_data("f101_factura_atr_empty_periods.xml"), "r") as f:
+        with open(get_data("f101_factura_atr_empty_periods.xml"), "rb") as f:
             self.xml_f101_atr_invoice_empty_periods = f.read()
-        with open(get_data("f101_factura_otros.xml"), "r") as f:
+        with open(get_data("f101_factura_otros.xml"), "rb") as f:
             self.xml_f101_other_invoice = f.read()
         with open(get_data("f101_spaces.xml"), "r") as f:
             self.xml_f101_spaces = f.read()
-        with open(get_data("f101_factura_atr_free_interpretation.xml"), "r") as f:
+        with open(get_data("f101_factura_atr_free_interpretation.xml"), "rb") as f:
             self.xml_f101_free_interpretation = f.read()
-        with open(get_data("f101_factura_empty_rent.xml"), "r") as f:
+        with open(get_data("f101_factura_empty_rent.xml"), "rb") as f:
             self.xml_f101_empty_rent = f.read()
-        with open(get_data("F1_periodos_DH.xml"), "r") as f:
+        with open(get_data("F1_periodos_DH.xml"), "rb") as f:
             self.xml_f101_integradores_dh = f.read()
 
     def testATRInvoice(self):
@@ -2047,8 +2058,8 @@ def test_sin_base_imponible(self):
 
         f1_sin_base = F1(
             self.xml_f101_atr_invoice.replace(
-                '<BaseImponible>63.21</BaseImponible>',
-                '<BaseImponible>0.0</BaseImponible>'
+                '<BaseImponible>63.21</BaseImponible>'.encode('utf-8'),
+                '<BaseImponible>0.0</BaseImponible>'.encode('utf-8')
             )
         )
         f1_sin_base.parse_xml()
@@ -2197,7 +2208,7 @@ def test_agrupar_i_obtenir_dates_maximetre(self):
         lectures_agrupades = agrupar_lectures_per_data(lectures)
 
         self.assertEqual(
-            lectures_agrupades.keys(),
+            list(lectures_agrupades.keys()),
             [
                 ('2017-03-31', u'2017-04-17'),  # Energy readings
                 ('2017-04-30', u'2017-04-30')   # Maximeter readings
@@ -2489,7 +2500,7 @@ def test_empty_rents_dont_return(self):
 
 class test_MessageGas(unittest.TestCase):
     def setUp(self):
-        self.xml_a241 = open(get_data("a241.xml"), "r")
+        self.xml_a241 = open(get_data("a241.xml"), "rb")
 
     def tearDown(self):
         self.xml_a241.close()
@@ -2507,10 +2518,10 @@ def test_gas_header(self):
 class test_A1_41(unittest.TestCase):
 
     def setUp(self):
-        self.xml_a241 = open(get_data("a241.xml"), "r")
-        self.xml_a341 = open(get_data("a341.xml"), "r")
-        self.xml_a441 = open(get_data("a441.xml"), "r")
-        self.xml_a3s41 = open(get_data("a3s41.xml"), "r")
+        self.xml_a241 = open(get_data("a241.xml"), "rb")
+        self.xml_a341 = open(get_data("a341.xml"), "rb")
+        self.xml_a441 = open(get_data("a441.xml"), "rb")
+        self.xml_a3s41 = open(get_data("a3s41.xml"), "rb")
 
     def tearDown(self):
         self.xml_a241.close()
@@ -2678,8 +2689,8 @@ def test_a3s41(self):
 class test_B70(unittest.TestCase):
 
     def setUp(self):
-        self.xml_b7031 = open(get_data("b7031.xml"), "r")
-        self.xml_b7032 = open(get_data("b7032.xml"), "r")
+        self.xml_b7031 = open(get_data("b7031.xml"), "rb")
+        self.xml_b7032 = open(get_data("b7032.xml"), "rb")
 
     def tearDown(self):
         self.xml_b7031.close()
@@ -3033,10 +3044,10 @@ def test_b7032(self):
 class test_A1_02(unittest.TestCase):
 
     def setUp(self):
-        self.xml_a202 = open(get_data("a202.xml"), "r")
-        self.xml_a302 = open(get_data("a302.xml"), "r")
-        self.xml_a3s02 = open(get_data("a3s02.xml"), "r")
-        self.xml_a402 = open(get_data("a402.xml"), "r")
+        self.xml_a202 = open(get_data("a202.xml"), "rb")
+        self.xml_a302 = open(get_data("a302.xml"), "rb")
+        self.xml_a3s02 = open(get_data("a3s02.xml"), "rb")
+        self.xml_a402 = open(get_data("a402.xml"), "rb")
 
     def tearDown(self):
         self.xml_a202.close()
@@ -3163,9 +3174,9 @@ def test_a402(self):
 class test_A1_05(unittest.TestCase):
 
     def setUp(self):
-        self.xml_a205 = open(get_data("a205.xml"), "r")
-        self.xml_a305 = open(get_data("a305.xml"), "r")
-        self.xml_a405 = open(get_data("a405.xml"), "r")
+        self.xml_a205 = open(get_data("a205.xml"), "rb")
+        self.xml_a305 = open(get_data("a305.xml"), "rb")
+        self.xml_a405 = open(get_data("a405.xml"), "rb")
 
     def tearDown(self):
         self.xml_a205.close()
@@ -3268,9 +3279,9 @@ def test_a405(self):
 class test_A1_44(unittest.TestCase):
 
     def setUp(self):
-        self.xml_a244 = open(get_data("a244.xml"), "r")
-        self.xml_a344 = open(get_data("a344.xml"), "r")
-        self.xml_a444 = open(get_data("a444.xml"), "r")
+        self.xml_a244 = open(get_data("a244.xml"), "rb")
+        self.xml_a344 = open(get_data("a344.xml"), "rb")
+        self.xml_a444 = open(get_data("a444.xml"), "rb")
 
     def tearDown(self):
         self.xml_a244.close()
@@ -3415,8 +3426,8 @@ def test_a444(self):
 class test_A1_03(unittest.TestCase):
 
     def setUp(self):
-        self.xml_a203 = open(get_data("a203.xml"), "r")
-        self.xml_a2s03 = open(get_data("a2s03.xml"), "r")
+        self.xml_a203 = open(get_data("a203.xml"), "rb")
+        self.xml_a2s03 = open(get_data("a2s03.xml"), "rb")
 
     def tearDown(self):
         self.xml_a203.close()
@@ -3459,9 +3470,9 @@ def test_a2s03(self):
 class test_A1_04(unittest.TestCase):
 
     def setUp(self):
-        self.xml_a204 = open(get_data("a204.xml"), "r")
-        self.xml_a304 = open(get_data("a304.xml"), "r")
-        self.xml_a404 = open(get_data("a404.xml"), "r")
+        self.xml_a204 = open(get_data("a204.xml"), "rb")
+        self.xml_a304 = open(get_data("a304.xml"), "rb")
+        self.xml_a404 = open(get_data("a404.xml"), "rb")
 
     def tearDown(self):
         self.xml_a204.close()
@@ -3570,11 +3581,11 @@ def test_a404(self):
 class test_A1_48(unittest.TestCase):
 
     def setUp(self):
-        self.xml_a148 = open(get_data("a148.xml"), "r")
-        self.xml_a248 = open(get_data("a248.xml"), "r")
-        self.xml_a2548 = open(get_data("a2548.xml"), "r")
-        self.xml_a2648 = open(get_data("a2648.xml"), "r")
-        self.xml_a348 = open(get_data("a348.xml"), "r")
+        self.xml_a148 = open(get_data("a148.xml"), "rb")
+        self.xml_a248 = open(get_data("a248.xml"), "rb")
+        self.xml_a2548 = open(get_data("a2548.xml"), "rb")
+        self.xml_a2648 = open(get_data("a2648.xml"), "rb")
+        self.xml_a348 = open(get_data("a348.xml"), "rb")
 
     def tearDown(self):
         self.xml_a148.close()
@@ -3857,7 +3868,7 @@ def test_a348(self):
 class test_A1_46(unittest.TestCase):
 
     def setUp(self):
-        self.xml_a246 = open(get_data("a246.xml"), "r")
+        self.xml_a246 = open(get_data("a246.xml"), "rb")
 
     def tearDown(self):
         self.xml_a246.close()
@@ -3881,7 +3892,7 @@ def test_a246(self):
 class test_A12_26(unittest.TestCase):
 
     def setUp(self):
-        self.xml_a1226 = open(get_data("a1226.xml"), "r")
+        self.xml_a1226 = open(get_data("a1226.xml"), "rb")
 
     def tearDown(self):
         self.xml_a1226.close()
@@ -3961,7 +3972,7 @@ def test_a246(self):
 class test_A19_45(unittest.TestCase):
 
     def setUp(self):
-        self.xml_a1945 = open(get_data("a1945.xml"), "r")
+        self.xml_a1945 = open(get_data("a1945.xml"), "rb")
 
     def tearDown(self):
         self.xml_a1945.close()
diff --git a/tests/test_output.py b/tests/test_output.py
index d2498a4b..3d596b94 100644
--- a/tests/test_output.py
+++ b/tests/test_output.py
@@ -1,5 +1,6 @@
 #!/usr/bin/env python
 # -*- coding: utf-8 -*-
+from __future__ import absolute_import, unicode_literals
 import copy
 
 from gestionatr.output.messages import sw_a1_02 as a1_02
@@ -28,14 +29,14 @@
 class test_C1(unittest.TestCase):
 
     def setUp(self):
-        self.xml_c101_completo = open(get_data("c101.xml"), "r")
-        self.xml_c102_accept = open(get_data("c102_accept.xml"), "r")
-        self.xml_c102_reject = open(get_data("c102_reject.xml"), "r")
-        self.xml_c105 = open(get_data("c105.xml"), "r")
-        self.xml_c106 = open(get_data("c106.xml"), "r")
-        self.xml_c109 = open(get_data("c109.xml"), "r")
-        self.xml_c111 = open(get_data("c111.xml"), "r")
-        self.xml_c112 = open(get_data("c112.xml"), "r")
+        self.xml_c101_completo = open(get_data("c101.xml"), "rb")
+        self.xml_c102_accept = open(get_data("c102_accept.xml"), "rb")
+        self.xml_c102_reject = open(get_data("c102_reject.xml"), "rb")
+        self.xml_c105 = open(get_data("c105.xml"), "rb")
+        self.xml_c106 = open(get_data("c106.xml"), "rb")
+        self.xml_c109 = open(get_data("c109.xml"), "rb")
+        self.xml_c111 = open(get_data("c111.xml"), "rb")
+        self.xml_c112 = open(get_data("c112.xml"), "rb")
 
         # RegistrosDocumento
         self.registros_documento = c1.RegistrosDocumento()
@@ -525,9 +526,9 @@ def test_create_pas12(self):
 class test_C2(unittest.TestCase):
 
     def setUp(self):
-        self.xml_c201_completo = open(get_data("c201.xml"), "r")
-        self.xml_c202_accept = open(get_data("c202_accept.xml"), "r")
-        self.xml_c203 = open(get_data("c203.xml"), "r")
+        self.xml_c201_completo = open(get_data("c201.xml"), "rb")
+        self.xml_c202_accept = open(get_data("c202_accept.xml"), "rb")
+        self.xml_c203 = open(get_data("c203.xml"), "rb")
 
     def tearDown(self):
         self.xml_c201_completo.close()
@@ -767,9 +768,9 @@ def test_create_pas03(self):
 class test_A1(unittest.TestCase):
 
         def setUp(self):
-            self.xml_a101 = open(get_data("a101.xml"), "r")
-            self.xml_a102_accept = open(get_data("a102_accept.xml"), "r")
-            self.xml_a102_reject = open(get_data("a102_reject.xml"), "r")
+            self.xml_a101 = open(get_data("a101.xml"), "rb")
+            self.xml_a102_accept = open(get_data("a102_accept.xml"), "rb")
+            self.xml_a102_reject = open(get_data("a102_reject.xml"), "rb")
 
         def tearDown(self):
             self.xml_a101.close()
@@ -1090,8 +1091,8 @@ def test_create_pas02_rej(self):
 
 class test_A3(unittest.TestCase):
     def setUp(self):
-        self.xml_a301 = open(get_data("a301.xml"), "r")
-        self.xml_a301_correos = open(get_data("a301_correos.xml"), "r")
+        self.xml_a301 = open(get_data("a301.xml"), "rb")
+        self.xml_a301_correos = open(get_data("a301_correos.xml"), "rb")
 
     def tearDown(self):
         self.xml_a301.close()
@@ -1328,7 +1329,7 @@ def test_create_pas01_correos(self):
 
 class test_M1(unittest.TestCase):
     def setUp(self):
-        self.xml_m101 = open(get_data("m101.xml"), "r")
+        self.xml_m101 = open(get_data("m101.xml"), "rb")
 
     def tearDown(self):
         self.xml_m101.close()
@@ -1418,9 +1419,9 @@ def test_create_pas01(self):
 class test_D1(unittest.TestCase):
 
     def setUp(self):
-        self.xml_d101 = open(get_data("d101.xml"), "r")
-        self.xml_d102_accept = open(get_data("d102_accept.xml"), "r")
-        self.xml_d102_reject = open(get_data("d102_reject.xml"), "r")
+        self.xml_d101 = open(get_data("d101.xml"), "rb")
+        self.xml_d102_accept = open(get_data("d102_accept.xml"), "rb")
+        self.xml_d102_reject = open(get_data("d102_reject.xml"), "rb")
 
     def tearDown(self):
         self.xml_d101.close()
@@ -1729,7 +1730,7 @@ def test_create_pas02_rej(self):
 class test_Q1(unittest.TestCase):
 
     def setUp(self):
-        self.xml_q101 = open(get_data("q101.xml"), "r")
+        self.xml_q101 = open(get_data("q101.xml"), "rb")
 
     def tearDown(self):
         self.xml_q101.close()
@@ -1905,9 +1906,9 @@ def test_create_pas01(self):
 class test_W1(unittest.TestCase):
 
     def setUp(self):
-        self.xml_w101 = open(get_data("w101.xml"), "r")
-        self.xml_w102_accept = open(get_data("w102_accept.xml"), "r")
-        self.xml_w102_reject = open(get_data("w102_reject.xml"), "r")
+        self.xml_w101 = open(get_data("w101.xml"), "rb")
+        self.xml_w102_accept = open(get_data("w102_accept.xml"), "rb")
+        self.xml_w102_reject = open(get_data("w102_reject.xml"), "rb")
 
     def tearDown(self):
         self.xml_w101.close()
@@ -2034,10 +2035,10 @@ def test_create_pas02_rej(self):
 class test_B1(unittest.TestCase):
 
     def setUp(self):
-        self.xml_b101 = open(get_data("b101.xml"), "r")
-        self.xml_b102_accept = open(get_data("b102_accept.xml"), "r")
-        self.xml_b104_accept = open(get_data("b104_accept.xml"), "r")
-        self.xml_b105 = open(get_data("b105.xml"), "r")
+        self.xml_b101 = open(get_data("b101.xml"), "rb")
+        self.xml_b102_accept = open(get_data("b102_accept.xml"), "rb")
+        self.xml_b104_accept = open(get_data("b104_accept.xml"), "rb")
+        self.xml_b105 = open(get_data("b105.xml"), "rb")
 
     def tearDown(self):
         self.xml_b101.close()
@@ -2306,12 +2307,12 @@ def test_create_pas05(self):
 class test_R1(unittest.TestCase):
 
     def setUp(self):
-        self.xml_r101 = open(get_data("r101.xml"), "r")
-        self.xml_r102_accept = open(get_data("r102_accept.xml"), "r")
-        self.xml_r103 = open(get_data("r103.xml"), "r")
-        self.xml_r103_intervenciones = open(get_data("r103_intervenciones.xml"), "r")
-        self.xml_r104 = open(get_data("r104.xml"), "r")
-        self.xml_r105 = open(get_data("r105.xml"), "r")
+        self.xml_r101 = open(get_data("r101.xml"), "rb")
+        self.xml_r102_accept = open(get_data("r102_accept.xml"), "rb")
+        self.xml_r103 = open(get_data("r103.xml"), "rb")
+        self.xml_r103_intervenciones = open(get_data("r103_intervenciones.xml"), "rb")
+        self.xml_r104 = open(get_data("r104.xml"), "rb")
+        self.xml_r105 = open(get_data("r105.xml"), "rb")
 
     def tearDown(self):
         self.xml_r101.close()
@@ -3018,15 +3019,15 @@ def test_create_pas05(self):
 class test_F1(unittest.TestCase):
 
     def setUp(self):
-        self.xml_f101_factura_atr = open(get_data("f101_factura_atr.xml"), "r")
+        self.xml_f101_factura_atr = open(get_data("f101_factura_atr.xml"), "rb")
         self.xml_f101_factura_otros = open(
-            get_data("f101_factura_otros.xml"), "r"
+            get_data("f101_factura_otros.xml"), "rb"
         )
         self.xml_f101_factura_atr_direccion_suministro = open(
-            get_data("f101_factura_atr_direccion_suministro.xml"), "r"
+            get_data("f101_factura_atr_direccion_suministro.xml"), "rb"
         )
         self.xml_f101_factura_atr_medidas_baja = open(
-            get_data("f101_factura_atr_medidas_baja.xml"), "r"
+            get_data("f101_factura_atr_medidas_baja.xml"), "rb"
         )
 
         direccion_suministro = f1.DireccionSuministro()
@@ -3426,6 +3427,9 @@ def setUp(self):
 
     def tearDown(self):
         self.xml_f101_factura_atr.close()
+        self.xml_f101_factura_otros.close()
+        self.xml_f101_factura_atr_direccion_suministro.close()
+        self.xml_f101_factura_atr_medidas_baja.close()
 
     def with_factura_atr(self):
         cabecera = get_header(process='F1', step='01')
@@ -3541,7 +3545,7 @@ def test_create_pas01_other_invoice(self):
 class test_A1_41(unittest.TestCase):
 
     def setUp(self):
-        self.xml_a141 = open(get_data("a141.xml"), "r")
+        self.xml_a141 = open(get_data("a141.xml"), "rb")
 
     def tearDown(self):
         self.xml_a141.close()
@@ -3642,7 +3646,7 @@ def test_create_a141(self):
 class test_A1_02(unittest.TestCase):
 
     def setUp(self):
-        self.xml_a102 = open(get_data("a102.xml"), "r")
+        self.xml_a102 = open(get_data("a102.xml"), "rb")
 
     def tearDown(self):
         self.xml_a102.close()
@@ -3696,7 +3700,7 @@ def test_create_a102(self):
 class test_A1_05(unittest.TestCase):
 
     def setUp(self):
-        self.xml_a105 = open(get_data("a105.xml"), "r")
+        self.xml_a105 = open(get_data("a105.xml"), "rb")
 
     def tearDown(self):
         self.xml_a105.close()
@@ -3797,7 +3801,7 @@ def test_create_a105(self):
 class test_A1_44(unittest.TestCase):
 
     def setUp(self):
-        self.xml_a144 = open(get_data("a144.xml"), "r")
+        self.xml_a144 = open(get_data("a144.xml"), "rb")
 
     def tearDown(self):
         self.xml_a144.close()
@@ -3879,7 +3883,7 @@ def test_create_a144(self):
 class test_A1_03(unittest.TestCase):
 
     def setUp(self):
-        self.xml_a103 = open(get_data("a103.xml"), "r")
+        self.xml_a103 = open(get_data("a103.xml"), "rb")
 
     def tearDown(self):
         self.xml_a103.close()
@@ -3930,7 +3934,7 @@ def test_create_a103(self):
 class test_A1_04(unittest.TestCase):
 
     def setUp(self):
-        self.xml_a104 = open(get_data("a104.xml"), "r")
+        self.xml_a104 = open(get_data("a104.xml"), "rb")
 
     def tearDown(self):
         self.xml_a104.close()
@@ -3989,8 +3993,8 @@ def test_create_a104(self):
 class test_A1_48(unittest.TestCase):
 
     def setUp(self):
-        self.xml_a148 = open(get_data("a148.xml"), "r")
-        self.xml_a2648 = open(get_data("a2648.xml"), "r")
+        self.xml_a148 = open(get_data("a148.xml"), "rb")
+        self.xml_a2648 = open(get_data("a2648.xml"), "rb")
 
     def tearDown(self):
         self.xml_a148.close()
@@ -4427,7 +4431,7 @@ def test_create_a2648(self):
 class test_A1_46(unittest.TestCase):
 
     def setUp(self):
-        self.xml_a146 = open(get_data("a146.xml"), "r")
+        self.xml_a146 = open(get_data("a146.xml"), "rb")
 
     def tearDown(self):
         self.xml_a146.close()
diff --git a/tests/utils.py b/tests/utils.py
index 2bffe214..cf05cb37 100644
--- a/tests/utils.py
+++ b/tests/utils.py
@@ -193,6 +193,13 @@ def get_medida():
 def assertXmlEqual(got, want):
     from lxml.doctestcompare import LXMLOutputChecker
     from doctest import Example
+    import six
+
+    if isinstance(want, six.binary_type):
+        from lxml import etree
+        from io import BytesIO
+        x = etree.parse(BytesIO(want))
+        want = etree.tostring(x, encoding='unicode')
 
     checker = LXMLOutputChecker()
     if checker.check_output(want, got, 0):