Make mock optional and use unittest.mock

The mock package is not available on some target platforms. An optional
dependenyc allows us to run a subset of tests on these platforms.

Starting with Python 3.3, the mock package is available as
unittest.mock. The variant in stdlib is a bit more strict, too.

Signed-off-by: Christian Heimes <[email protected]>

setup.py

@@ -2,18 +2,36 @@
 #
 # Copyright (C) 2016  Custodia project Contributors, for licensee see COPYING
 
+import sys
+
+import setuptools
 from setuptools import setup
 
+SETUPTOOLS_VERSION = tuple(int(v) for v in setuptools.__version__.split("."))
+
+
 requirements = [
     'custodia >= 0.4.0',
     'ipalib >= 4.5.0',
     'ipaclient >= 4.5.0',
     'six',
 ]
 # test requirements
-test_requires = ['coverage', 'pytest', 'mock']
-test_pylint_requires = ['pylint'] + test_requires
-test_pep8_requires = ['flake8', 'flake8-import-order', 'pep8-naming']
+test_requires = ['coverage', 'pytest']
+
+extras_require = {
+    'test': test_requires,
+    'test_docs': ['docutils', 'markdown'],
+    'test_pep8': ['flake8', 'flake8-import-order', 'pep8-naming'],
+    'test_pylint': ['pylint'] + test_requires,
+}
+
+# backwards compatibility with old setuptools
+# unittest.mock was added in Python 3.3
+if SETUPTOOLS_VERSION < (18, 0, 0) and sys.version_info < (3, 3):
+    requirements.append('mock')
+else:
+    extras_require[':python_version<"3.3"'] = ['mock']
 
 
 with open('README') as f:
@@ -55,10 +73,5 @@
     ],
     install_requires=requirements,
     tests_require=test_requires,
-    extras_require={
-        'test': test_requires,
-        'test_docs': ['docutils', 'markdown'],
-        'test_pep8': test_pep8_requires,
-        'test_pylint': test_pylint_requires,
-    },
+    extras_require=extras_require,
 )

tests.py

@@ -11,8 +11,6 @@
 import ipalib
 from ipalib.errors import NotFound
 
-import mock
-
 import pkg_resources
 
 import pytest
@@ -22,6 +20,14 @@
 from custodia.ipa.interface import IPAInterface
 from custodia.ipa.vault import IPAVault, krb5_unparse_principal_name
 
+try:
+    from unittest import mock
+except ImportError:
+    try:
+        import mock
+    except ImportError:
+        mock = None
+
 
 CONFIG = u"""
 [store:ipa_service]
@@ -150,7 +156,6 @@
 -----END CERTIFICATE-----
 """
 
-
 vault_parametrize = pytest.mark.parametrize(
     'plugin,vault_type,vault_args',
     [
@@ -161,6 +166,7 @@
 )
 
 
+@pytest.mark.skipif(mock is None, reason='requires mock')
 class BaseTest(object):
     def setup_method(self, method):
         self.parser = configparser.ConfigParser(
@@ -218,9 +224,9 @@ def test_api_init(self):
 
         m_api.Backend.rpcclient.isconnected.return_value = False
         with ipa:
-            m_api.Backend.rpcclient.connect.assert_called()
+            m_api.Backend.rpcclient.connect.assert_any_call()
             m_api.Backend.rpcclient.isconnected.return_value = True
-        m_api.Backend.rpcclient.disconnect.assert_called()
+        m_api.Backend.rpcclient.disconnect.assert_any_call()
 
         assert os.environ == dict(
             NSS_STRICT_NOFORK='DISABLED',
@@ -262,7 +268,7 @@ def test_vault_set(self, plugin, vault_type, vault_args):
         ipa = self.mkinstance('[email protected]', 'store:ipa_autodiscover')
         ipa = IPAVault(self.parser, plugin)
         assert ipa.vault_type == vault_type
-        self.m_api.Command.ping.assert_called_once()
+        self.m_api.Command.ping.assert_called_once_with()
         ipa.set('directory/testkey', 'testvalue')
         self.m_api.Command.vault_add.assert_called_once_with(
             'directory__testkey',