diff --git a/compose/__main__.py b/compose/__main__.py
index 199ba2ae9..27a7acbb8 100644
--- a/compose/__main__.py
+++ b/compose/__main__.py
@@ -1,3 +1,6 @@
+from __future__ import absolute_import
+from __future__ import unicode_literals
+
 from compose.cli.main import main
 
 main()
diff --git a/compose/config/sort_services.py b/compose/config/sort_services.py
index 5d9adab11..055521227 100644
--- a/compose/config/sort_services.py
+++ b/compose/config/sort_services.py
@@ -1,3 +1,6 @@
+from __future__ import absolute_import
+from __future__ import unicode_literals
+
 from compose.config.errors import DependencyError
 
 
diff --git a/compose/config/validation.py b/compose/config/validation.py
index f2162a874..74dd461f3 100644
--- a/compose/config/validation.py
+++ b/compose/config/validation.py
@@ -254,7 +254,8 @@ def _parse_oneof_validator(error):
             )
             return "{}contains {}, which is an invalid type, it should be {}".format(
                 invalid_config_key,
-                context.instance,
+                # Always print the json repr of the invalid value
+                json.dumps(context.instance),
                 _parse_valid_types_from_validator(context.validator_value))
 
         if context.validator == 'uniqueItems':
diff --git a/compose/volume.py b/compose/volume.py
index 055bd6abd..fb8bd5809 100644
--- a/compose/volume.py
+++ b/compose/volume.py
@@ -1,3 +1,4 @@
+from __future__ import absolute_import
 from __future__ import unicode_literals
 
 
diff --git a/script/travis/render-bintray-config.py b/script/travis/render-bintray-config.py
index c2b11ca3f..b5364a0b6 100755
--- a/script/travis/render-bintray-config.py
+++ b/script/travis/render-bintray-config.py
@@ -1,6 +1,6 @@
 #!/usr/bin/env python
-from __future__ import print_function
 from __future__ import absolute_import
+from __future__ import print_function
 from __future__ import unicode_literals
 
 import datetime
diff --git a/tests/integration/volume_test.py b/tests/integration/volume_test.py
index b60860400..8ae35378a 100644
--- a/tests/integration/volume_test.py
+++ b/tests/integration/volume_test.py
@@ -1,3 +1,4 @@
+from __future__ import absolute_import
 from __future__ import unicode_literals
 
 from docker.errors import DockerException
diff --git a/tests/unit/config/config_test.py b/tests/unit/config/config_test.py
index 8cb5d9b26..abb891a27 100644
--- a/tests/unit/config/config_test.py
+++ b/tests/unit/config/config_test.py
@@ -552,7 +552,9 @@ class ConfigTest(unittest.TestCase):
             )
 
     def test_config_extra_hosts_list_of_dicts_validation_error(self):
-        expected_error_msg = "key 'extra_hosts' contains {'somehost': '162.242.195.82'}, which is an invalid type, it should be a string"
+        expected_error_msg = (
+            "key 'extra_hosts' contains {\"somehost\": \"162.242.195.82\"}, "
+            "which is an invalid type, it should be a string")
 
         with self.assertRaisesRegexp(ConfigurationError, expected_error_msg):
             config.load(
diff --git a/tests/unit/config/types_test.py b/tests/unit/config/types_test.py
index 4df665485..245b854ff 100644
--- a/tests/unit/config/types_test.py
+++ b/tests/unit/config/types_test.py
@@ -1,3 +1,6 @@
+from __future__ import absolute_import
+from __future__ import unicode_literals
+
 import pytest
 
 from compose.config.errors import ConfigurationError