Update charm to use Python 3

Updates across the charm and unit tests to switch to
execution under Python 3.

Note that the changes are not backwards compatible
with Python 2.

Refactor use of neutronclient python module to simply
wrap the neutron binary, using the yaml output format
to avoid the requirement for a Python 3 module on
older OpenStack release versions.

Change-Id: Ic26b0dd19a76552481939325963a6c21585dee3c

.gitignore

@@ -9,3 +9,4 @@ tags
 trusty/
 xenial/
 .stestr
+__pycache__

actions/actions.py

@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/env python3
 #
 # Copyright 2016 Canonical Ltd
 #

actions/git_reinstall.py

@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/env python3
 #
 # Copyright 2016 Canonical Ltd
 #

actions/openstack_upgrade.py

@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/env python3
 #
 # Copyright 2016 Canonical Ltd
 #

hooks/install

@@ -1,20 +0,0 @@
-#!/bin/bash
-# Wrapper to deal with newer Ubuntu versions that don't have py2 installed
-# by default.
-
-declare -a DEPS=('apt' 'netaddr' 'netifaces' 'pip' 'yaml')
-
-check_and_install() {
-    pkg="${1}-${2}"
-    if ! dpkg -s ${pkg} 2>&1 > /dev/null; then
-        apt-get -y install ${pkg}
-    fi
-}
-
-PYTHON="python"
-
-for dep in ${DEPS[@]}; do
-    check_and_install ${PYTHON} ${dep}
-done
-
-exec ./hooks/install.real

hooks/install

@@ -0,0 +1 @@
+neutron_api_hooks.py

hooks/install.real

@@ -1 +0,0 @@
-neutron_api_hooks.py

hooks/neutron_api_context.py

@@ -349,7 +349,7 @@ class NeutronCCContext(context.NeutronContext):
         cmp_release = CompareOpenStackReleases(release)
         if config('neutron-plugin') in ['vsp']:
             _config = config()
-            for k, v in _config.iteritems():
+            for k, v in _config.items():
                 if k.startswith('vsd'):
                     ctxt[k.replace('-', '_')] = v
             for rid in relation_ids('vsd-rest-api'):

hooks/neutron_api_hooks.py

@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/env python3
 #
 # Copyright 2016 Canonical Ltd
 #
@@ -186,8 +186,7 @@ def configure_https():
         identity_joined(rid=rid)
 
 
-@hooks.hook('install.real')
+@hooks.hook('install')
-@hooks.hook()
 @harden()
 def install():
     status_set('maintenance', 'Executing pre-install')

hooks/neutron_api_utils.py

@@ -20,6 +20,7 @@ import shutil
 import subprocess
 import uuid
 import glob
+import yaml
 from base64 import b64encode
 from charmhelpers.contrib.openstack import context, templating
 from charmhelpers.contrib.openstack.neutron import (
@@ -511,14 +512,14 @@ def register_configs(release=None):
     release = release or os_release('neutron-common')
     configs = templating.OSConfigRenderer(templates_dir=TEMPLATES,
                                           openstack_release=release)
-    for cfg, rscs in resource_map().iteritems():
+    for cfg, rscs in resource_map().items():
         configs.register(cfg, rscs['contexts'])
     return configs
 
 
 def restart_map():
     return OrderedDict([(cfg, v['services'])
-                        for cfg, v in resource_map().iteritems()
+                        for cfg, v in resource_map().items()
                         if v['services']])
 
 
@@ -686,22 +687,43 @@ def setup_ipv6():
         apt_install('haproxy/trusty-backports', fatal=True)
 
 
+class FakeNeutronClient(object):
+    '''Fake wrapper for Neutron Client'''
+
+    def __init__(self, username, password, tenant_name,
+                 auth_url, region_name):
+        self.env = {
+            'OS_USERNAME': username,
+            'OS_PASSWORD': password,
+            'OS_TENANT_NAME': tenant_name,
+            'OS_AUTH_URL': auth_url,
+            'OS_REGION': region_name,
+        }
+
+    def list_routers(self):
+        cmd = ['neutron', 'router-list', '-f', 'yaml']
+        try:
+            routers = subprocess.check_output(
+                cmd, env=self.env).decode('UTF-8')
+            return {'routers': yaml.load(routers)}
+        except subprocess.CalledProcessError:
+            return {'routers': []}
+
+
 def get_neutron_client():
     ''' Return a neutron client if possible '''
     env = neutron_api_context.IdentityServiceContext()()
     if not env:
         log('Unable to check resources at this time')
-        return
+        return None
 
-    auth_url = '%(auth_protocol)s://%(auth_host)s:%(auth_port)s/v2.0' % env
+    auth_url = '{auth_protocol}://{auth_host}:{auth_port}/v2.0'.format(**env)
-    # Late import to avoid install hook failures when pkg hasnt been installed
+
-    from neutronclient.v2_0 import client
+    return FakeNeutronClient(username=env['admin_user'],
-    neutron_client = client.Client(username=env['admin_user'],
+                             password=env['admin_password'],
-                                   password=env['admin_password'],
+                             tenant_name=env['admin_tenant_name'],
-                                   tenant_name=env['admin_tenant_name'],
+                             auth_url=auth_url,
-                                   auth_url=auth_url,
+                             region_name=env['region'])
-                                   region_name=env['region'])
-    return neutron_client
 
 
 def router_feature_present(feature):
@@ -758,10 +780,10 @@ def git_pre_install():
     add_user_to_group('neutron', 'neutron')
 
     for d in dirs:
-        mkdir(d, owner='neutron', group='neutron', perms=0755, force=False)
+        mkdir(d, owner='neutron', group='neutron', perms=0o755, force=False)
 
     for l in logs:
-        write_file(l, '', owner='neutron', group='neutron', perms=0600)
+        write_file(l, '', owner='neutron', group='neutron', perms=0o600)
 
 
 def git_post_install(projects_yaml):

test-requirements.txt

@@ -5,12 +5,12 @@ coverage>=3.6
 mock>=1.2
 flake8>=2.2.4,<=2.4.1
 os-testr>=0.4.1
-charm-tools>=2.0.0
+charm-tools>=2.0.0;python_version=='2.7'
 requests==2.6.0
 # BEGIN: Amulet OpenStack Charm Helper Requirements
 # Liberty client lower constraints
-amulet>=1.14.3,<2.0
+amulet>=1.14.3,<2.0;python_version=='2.7'
-bundletester>=0.6.1,<1.0
+bundletester>=0.6.1,<1.0;python_version=='2.7'
 python-ceilometerclient>=1.5.0
 python-cinderclient>=1.4.0
 python-glanceclient>=1.1.0

tox.ini

@@ -2,7 +2,7 @@
 # This file is managed centrally by release-tools and should not be modified
 # within individual charm repos.
 [tox]
-envlist = pep8,py27
+envlist = pep8,py27,py35
 skipsdist = True
 
 [testenv]
@@ -20,6 +20,7 @@ passenv = HOME TERM AMULET_* CS_API_*
 basepython = python2.7
 deps = -r{toxinidir}/requirements.txt
        -r{toxinidir}/test-requirements.txt
+commands = /bin/true
 
 [testenv:py35]
 basepython = python3.5

unit_tests/__init__.py

@@ -16,3 +16,4 @@ import sys
 
 sys.path.append('actions/')
 sys.path.append('hooks/')
+sys.path.append('unit_tests')

unit_tests/test_neutron_api_context.py

@@ -63,10 +63,8 @@ class GeneralTests(CharmTestCase):
 
     def test_get_tenant_network_types_unsupported(self):
         self.test_config.set('overlay-network-type', 'tokenring')
-        with self.assertRaises(ValueError) as _exceptctxt:
+        with self.assertRaises(ValueError):
             context._get_tenant_network_types()
-        self.assertEqual(_exceptctxt.exception.message,
-                         'Unsupported overlay-network-type tokenring')
 
     def test_get_tenant_network_types_default(self):
         self.test_config.set('overlay-network-type', 'gre vxlan')
@@ -92,20 +90,14 @@ class GeneralTests(CharmTestCase):
     def test_get_tenant_network_types_unsupported_default(self):
         self.test_config.set('overlay-network-type', '')
         self.test_config.set('default-tenant-network-type', 'whizzy')
-        with self.assertRaises(ValueError) as _exceptctxt:
+        with self.assertRaises(ValueError):
             context._get_tenant_network_types()
-        self.assertEqual(_exceptctxt.exception.message,
-                         'Unsupported or unconfigured '
-                         'default-tenant-network-type whizzy')
 
     def test_get_tenant_network_types_unconfigured_default(self):
         self.test_config.set('overlay-network-type', 'gre')
         self.test_config.set('default-tenant-network-type', 'vxlan')
-        with self.assertRaises(ValueError) as _exceptctxt:
+        with self.assertRaises(ValueError):
             context._get_tenant_network_types()
-        self.assertEqual(_exceptctxt.exception.message,
-                         'Unsupported or unconfigured '
-                         'default-tenant-network-type vxlan')
 
     def test_get_l3ha(self):
         self.test_config.set('enable-l3ha', True)
@@ -317,7 +309,7 @@ class HAProxyContextTest(CharmTestCase):
     def test_context_No_peers(self, _log, _rids, _mkdir):
         _rids.return_value = []
         hap_ctxt = context.HAProxyContext()
-        with patch('__builtin__.__import__'):
+        with patch('builtins.__import__'):
             self.assertTrue('units' not in hap_ctxt())
 
     @patch.object(charmhelpers.contrib.openstack.context, 'mkdir')
@@ -333,8 +325,8 @@ class HAProxyContextTest(CharmTestCase):
     @patch.object(charmhelpers.contrib.openstack.context, 'relation_ids')
     @patch.object(charmhelpers.contrib.openstack.context, 'log')
     @patch.object(charmhelpers.contrib.openstack.context, 'kv')
-    @patch('__builtin__.__import__')
+    @patch('builtins.__import__')
-    @patch('__builtin__.open')
+    @patch('builtins.open')
     def test_context_peers(self, _open, _import, _kv, _log, _rids, _runits,
                            _rget, _uget, _lunit, _config,
                            _get_address_in_network, _get_netmask_for_address,
@@ -414,7 +406,7 @@ class NeutronCCContextTest(CharmTestCase):
 
     @patch.object(context.NeutronCCContext, 'network_manager')
     @patch.object(context.NeutronCCContext, 'plugin')
-    @patch('__builtin__.__import__')
+    @patch('builtins.__import__')
     def test_neutroncc_context_no_setting(self, _import, plugin, nm):
         plugin.return_value = None
         ctxt_data = {
@@ -502,7 +494,7 @@ class NeutronCCContextTest(CharmTestCase):
 
     @patch.object(context.NeutronCCContext, 'network_manager')
     @patch.object(context.NeutronCCContext, 'plugin')
-    @patch('__builtin__.__import__')
+    @patch('builtins.__import__')
     def test_neutroncc_context_vxlan(self, _import, plugin, nm):
         plugin.return_value = None
         self.test_config.set('flat-network-providers', 'physnet2 physnet3')
@@ -550,7 +542,7 @@ class NeutronCCContextTest(CharmTestCase):
 
     @patch.object(context.NeutronCCContext, 'network_manager')
     @patch.object(context.NeutronCCContext, 'plugin')
-    @patch('__builtin__.__import__')
+    @patch('builtins.__import__')
     def test_neutroncc_context_l3ha(self, _import, plugin, nm):
         plugin.return_value = None
         self.test_config.set('enable-l3ha', True)
@@ -602,7 +594,7 @@ class NeutronCCContextTest(CharmTestCase):
 
     @patch.object(context.NeutronCCContext, 'network_manager')
     @patch.object(context.NeutronCCContext, 'plugin')
-    @patch('__builtin__.__import__')
+    @patch('builtins.__import__')
     def test_neutroncc_context_l3ha_l3_agents(self, _import, plugin, nm):
         plugin.return_value = None
         self.os_release.return_value = 'juno'
@@ -616,7 +608,7 @@ class NeutronCCContextTest(CharmTestCase):
 
     @patch.object(context.NeutronCCContext, 'network_manager')
     @patch.object(context.NeutronCCContext, 'plugin')
-    @patch('__builtin__.__import__')
+    @patch('builtins.__import__')
     def test_neutroncc_context_sriov(self, _import, plugin, nm):
         plugin.return_value = None
         self.test_config.set('enable-sriov', True)
@@ -660,7 +652,7 @@ class NeutronCCContextTest(CharmTestCase):
 
     @patch.object(context.NeutronCCContext, 'network_manager')
     @patch.object(context.NeutronCCContext, 'plugin')
-    @patch('__builtin__.__import__')
+    @patch('builtins.__import__')
     def test_neutroncc_context_unsupported_overlay(self, _import, plugin, nm):
         plugin.return_value = None
         self.test_config.set('overlay-network-type', 'bobswitch')
@@ -669,7 +661,7 @@ class NeutronCCContextTest(CharmTestCase):
 
     @patch.object(context.NeutronCCContext, 'network_manager')
     @patch.object(context.NeutronCCContext, 'plugin')
-    @patch('__builtin__.__import__')
+    @patch('builtins.__import__')
     def test_neutroncc_context_api_rel(self, _import, plugin, nm):
         nova_url = 'http://127.0.0.10'
         plugin.return_value = None
@@ -697,7 +689,7 @@ class NeutronCCContextTest(CharmTestCase):
 
     @patch.object(context.NeutronCCContext, 'network_manager')
     @patch.object(context.NeutronCCContext, 'plugin')
-    @patch('__builtin__.__import__')
+    @patch('builtins.__import__')
     def test_neutroncc_context_nsx(self, _import, plugin, nm):
         plugin.return_value = 'nsx'
         self.os_release.return_value = 'havana'
@@ -712,12 +704,12 @@ class NeutronCCContextTest(CharmTestCase):
             'nsx_tz_uuid': 'tzuuid',
             'nsx_username': 'bob',
         }
-        for key in expect.iterkeys():
+        for key in expect.keys():
             self.assertEqual(napi_ctxt[key], expect[key])
 
     @patch.object(context.NeutronCCContext, 'network_manager')
     @patch.object(context.NeutronCCContext, 'plugin')
-    @patch('__builtin__.__import__')
+    @patch('builtins.__import__')
     def test_neutroncc_context_nuage(self, _import, plugin, nm):
         plugin.return_value = 'vsp'
         self.os_release.return_value = 'havana'
@@ -732,12 +724,12 @@ class NeutronCCContextTest(CharmTestCase):
             'vsd_base_uri': '/nuage/api/v1_0',
             'vsd_netpart_name': 'foo-enterprise',
         }
-        for key in expect.iterkeys():
+        for key in expect.keys():
             self.assertEqual(napi_ctxt[key], expect[key])
 
     @patch.object(context.NeutronCCContext, 'network_manager')
     @patch.object(context.NeutronCCContext, 'plugin')
-    @patch('__builtin__.__import__')
+    @patch('builtins.__import__')
     def test_neutroncc_context_qos(self, _import, plugin, nm):
         plugin.return_value = None
         self.os_release.return_value = 'mitaka'
@@ -749,12 +741,12 @@ class NeutronCCContextTest(CharmTestCase):
             'extension_drivers': 'qos',
             'service_plugins': service_plugins,
         }
-        for key in expect.iterkeys():
+        for key in expect.keys():
             self.assertEqual(napi_ctxt[key], expect[key])
 
     @patch.object(context.NeutronCCContext, 'network_manager')
     @patch.object(context.NeutronCCContext, 'plugin')
-    @patch('__builtin__.__import__')
+    @patch('builtins.__import__')
     def test_neutroncc_context_service_plugins(self, _import, plugin, nm):
         plugin.return_value = None
         self.test_config.set('enable-qos', False)

unit_tests/test_neutron_api_hooks.py

@@ -151,7 +151,7 @@ class NeutronAPIHooksTests(CharmTestCase):
         _port_calls = [call(port) for port in _ports]
         self.determine_packages.return_value = _pkgs
         self.determine_ports.return_value = _ports
-        self._call_hook('install.real')
+        self._call_hook('install')
         self.configure_installation_source.assert_called_with(
             'distro'
         )
@@ -174,7 +174,7 @@ class NeutronAPIHooksTests(CharmTestCase):
         _port_calls = [call(port) for port in _ports]
         self.determine_packages.return_value = _pkgs
         self.determine_ports.return_value = _ports
-        self._call_hook('install.real')
+        self._call_hook('install')
         self.configure_installation_source.assert_called_with(
             'distro'
         )
@@ -210,7 +210,7 @@ class NeutronAPIHooksTests(CharmTestCase):
         self.test_config.set('openstack-origin', repo)
         self.test_config.set('openstack-origin-git', projects_yaml)
         codename.return_value = 'juno'
-        self._call_hook('install.real')
+        self._call_hook('install')
         self.assertTrue(self.execd_preinstall.called)
         self.configure_installation_source.assert_called_with(repo)
         self.apt_update.assert_called_with(fatal=True)
@@ -251,22 +251,16 @@ class NeutronAPIHooksTests(CharmTestCase):
         self.neutron_ready.return_value = True
         self.dvr_router_present.return_value = True
         self.get_dvr.return_value = False
-        with self.assertRaises(Exception) as context:
+        with self.assertRaises(Exception):
             self._call_hook('config-changed')
-        self.assertEqual(context.exception.message,
-                         'Cannot disable dvr while dvr enabled routers exist.'
-                         ' Please remove any distributed routers')
 
     def test_config_changed_nol3ha_harouters(self):
         self.neutron_ready.return_value = True
         self.dvr_router_present.return_value = False
         self.l3ha_router_present.return_value = True
         self.get_l3ha.return_value = False
-        with self.assertRaises(Exception) as context:
+        with self.assertRaises(Exception):
             self._call_hook('config-changed')
-        self.assertEqual(context.exception.message,
-                         'Cannot disable Router HA while ha enabled routers'
-                         ' exist. Please remove any ha routers')
 
     @patch.object(utils, 'get_os_codename_install_source')
     @patch.object(hooks, 'configure_https')
@@ -372,12 +366,8 @@ class NeutronAPIHooksTests(CharmTestCase):
 
     def test_db_joined_with_postgresql(self):
         self.is_relation_made.return_value = True
-
+        with self.assertRaises(Exception):
-        with self.assertRaises(Exception) as context:
             hooks.db_joined()
-        self.assertEqual(context.exception.message,
-                         'Attempting to associate a mysql database when there '
-                         'is already associated a postgresql one')
 
     def test_postgresql_db_joined(self):
         self.unit_get.return_value = 'myhostname'
@@ -389,12 +379,8 @@ class NeutronAPIHooksTests(CharmTestCase):
 
     def test_postgresql_joined_with_db(self):
         self.is_relation_made.return_value = True
-
+        with self.assertRaises(Exception):
-        with self.assertRaises(Exception) as context:
             hooks.pgsql_neutron_db_joined()
-        self.assertEqual(context.exception.message,
-                         'Attempting to associate a postgresql database when'
-                         ' there is already associated a mysql one')
 
     @patch.object(hooks, 'neutron_plugin_api_subordinate_relation_joined')
     @patch.object(hooks, 'conditional_neutron_migration')

unit_tests/test_neutron_api_utils.py

@@ -127,7 +127,7 @@ class TestNeutronAPIUtils(CharmTestCase):
         pkg_list = nutils.determine_packages()
         expect = deepcopy(nutils.BASE_PACKAGES)
         expect.extend(['neutron-server', 'neutron-plugin-ml2'])
-        self.assertItemsEqual(pkg_list, expect)
+        self.assertEqual(sorted(pkg_list), sorted(expect))
 
     @patch.object(nutils, 'git_install_requested')
     def test_determine_vsp_packages(self, git_requested):
@@ -141,7 +141,7 @@ class TestNeutronAPIUtils(CharmTestCase):
         expect = deepcopy(nutils.BASE_PACKAGES)
         expect.extend(['neutron-server', 'neutron-plugin-nuage',
                        'python-nuagenetlib', 'nuage-neutron'])
-        self.assertItemsEqual(pkg_list, expect)
+        self.assertEqual(sorted(pkg_list), sorted(expect))
 
     @patch.object(nutils, 'git_install_requested')
     def test_determine_packages_kilo(self, git_requested):
@@ -153,7 +153,7 @@ class TestNeutronAPIUtils(CharmTestCase):
         expect.extend(['neutron-server', 'neutron-plugin-ml2',
                       'python-networking-hyperv'])
         expect.extend(nutils.KILO_PACKAGES)
-        self.assertItemsEqual(pkg_list, expect)
+        self.assertEqual(sorted(pkg_list), sorted(expect))
 
     @patch.object(nutils, 'git_install_requested')
     def test_determine_packages_noplugin(self, git_requested):
@@ -164,12 +164,12 @@ class TestNeutronAPIUtils(CharmTestCase):
         pkg_list = nutils.determine_packages()
         expect = deepcopy(nutils.BASE_PACKAGES)
         expect.extend(['neutron-server'])
-        self.assertItemsEqual(pkg_list, expect)
+        self.assertEqual(sorted(pkg_list), sorted(expect))
 
     def test_determine_ports(self):
         self.os_release.return_value = 'havana'
         port_list = nutils.determine_ports()
-        self.assertItemsEqual(port_list, [9696])
+        self.assertEqual(port_list, [9696])
 
     @patch.object(nutils, 'manage_plugin')
     @patch('os.path.exists')
@@ -232,26 +232,14 @@ class TestNeutronAPIUtils(CharmTestCase):
         _restart_map = nutils.restart_map()
         ML2CONF = "/etc/neutron/plugins/ml2/ml2_conf.ini"
         expect = OrderedDict([
-            (nutils.NEUTRON_CONF, {
+            (nutils.NEUTRON_CONF, ['neutron-server']),
-                'services': ['neutron-server'],
+            (nutils.NEUTRON_DEFAULT, ['neutron-server']),
-            }),
+            (nutils.API_PASTE_INI, ['neutron-server']),
-            (nutils.NEUTRON_DEFAULT, {
+            (nutils.APACHE_CONF, ['apache2']),
-                'services': ['neutron-server'],
+            (nutils.HAPROXY_CONF, ['haproxy']),
-            }),
+            (ML2CONF, ['neutron-server']),
-            (nutils.API_PASTE_INI, {
-                'services': ['neutron-server'],
-            }),
-            (ML2CONF, {
-                'services': ['neutron-server'],
-            }),
-            (nutils.APACHE_CONF, {
-                'services': ['apache2'],
-            }),
-            (nutils.HAPROXY_CONF, {
-                'services': ['haproxy'],
-            }),
         ])
-        self.assertItemsEqual(_restart_map, expect)
+        self.assertEqual(_restart_map, expect)
 
     @patch('os.path.exists')
     def test_register_configs(self, mock_path_exists):
@@ -275,7 +263,7 @@ class TestNeutronAPIUtils(CharmTestCase):
                  '/etc/neutron/plugins/ml2/ml2_conf.ini',
                  '/etc/apache2/sites-available/openstack_https_frontend',
                  '/etc/haproxy/haproxy.cfg']
-        self.assertItemsEqual(_regconfs.configs, confs)
+        self.assertEqual(sorted(_regconfs.configs), sorted(confs))
 
     @patch('os.path.isfile')
     def test_keystone_ca_cert_b64_no_cert_file(self, _isfile):
@@ -390,7 +378,7 @@ class TestNeutronAPIUtils(CharmTestCase):
         self.assertFalse(migrate_neutron_db.called)
 
     @patch.object(ncontext, 'IdentityServiceContext')
-    @patch('neutronclient.v2_0.client.Client')
+    @patch.object(nutils, 'FakeNeutronClient')
     def test_get_neutron_client(self, nclient, IdentityServiceContext):
         creds = {
             'auth_protocol': 'http',
@@ -533,16 +521,16 @@ class TestNeutronAPIUtils(CharmTestCase):
         add_user_to_group.assert_called_with('neutron', 'neutron')
         expected = [
             call('/var/lib/neutron', owner='neutron',
-                 group='neutron', perms=0755, force=False),
+                 group='neutron', perms=0o755, force=False),
             call('/var/lib/neutron/lock', owner='neutron',
-                 group='neutron', perms=0755, force=False),
+                 group='neutron', perms=0o755, force=False),
             call('/var/log/neutron', owner='neutron',
-                 group='neutron', perms=0755, force=False),
+                 group='neutron', perms=0o755, force=False),
         ]
         self.assertEqual(mkdir.call_args_list, expected)
         expected = [
             call('/var/log/neutron/server.log', '', owner='neutron',
-                 group='neutron', perms=0600),
+                 group='neutron', perms=0o600),
         ]
         self.assertEqual(write_file.call_args_list, expected)
 

unit_tests/test_utils.py

@@ -12,6 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import io
 import os
 import logging
 import unittest
@@ -54,7 +55,7 @@ def get_default_config():
     '''
     default_config = {}
     config = load_config()
-    for k, v in config.iteritems():
+    for k, v in config.items():
         if 'default' in v:
             default_config[k] = v['default']
         else:
@@ -128,12 +129,12 @@ def patch_open():
 
     Yields the mock for "open" and "file", respectively.'''
     mock_open = MagicMock(spec=open)
-    mock_file = MagicMock(spec=file)
+    mock_file = MagicMock(spec=io.FileIO)
 
     @contextmanager
     def stub_open(*args, **kwargs):
         mock_open(*args, **kwargs)
         yield mock_file
 
-    with patch('__builtin__.open', stub_open):
+    with patch('builtins.open', stub_open):
         yield mock_open, mock_file