add unit tests

Change-Id: I58995d162e67525b8c1a574ecf324013668ed49f

.stestr.conf

@@ -0,0 +1,3 @@
+[DEFAULT]
+test_path=./unit_tests
+top_dir=./

README.md

@@ -2,3 +2,19 @@
 
 Basic interface for sending Cinder-Backup external subordinate backend configuration.
 
+# Metadata
+
+To consume this interface in your charm or layer, add the following to layer.yaml:
+
+```
+includes: ['interface:cinder-backup']
+```
+
+and add a provides interface of type backup-backend to your charm or layers metadata.yaml:
+
+```
+provides:
+  backup-backend:
+    interface: cinder-backup
+    scope: container
+```

interface.yaml

@@ -2,3 +2,10 @@ name: cinder-backup
 summary: Interface to connect cinder-backup with external backend 
 version: 1
 repo: https://github.com/lolwww/interface-cinder-backup
+ignore:
+  - 'unit_tests'
+  - '.stestr.conf'
+  - 'test-requirements.txt'
+  - 'tox.ini'
+  - '.gitignore'
+  - '.travis.yml'

provides.py

@@ -19,5 +19,5 @@ class CinderBackupProvides(Endpoint):
 
     def publish(self, name, configuration):
         for relation in self.relations:
-            relation.to_publish_raw['backend_name'] = name
+            relation.to_publish['backend_name'] = name
             relation.to_publish['subordinate_configuration'] = configuration

test-requirements.txt

@@ -0,0 +1,7 @@
+# Lint and unit test requirements
+flake8
+os-testr>=0.4.1
+charms.reactive
+mock>=1.2
+coverage>=3.6
+git+https://github.com/openstack/charms.openstack.git#egg=charms.openstack

tox.ini

@@ -0,0 +1,60 @@
+[tox]
+skipsdist = True
+envlist = pep8,py35
+skip_missing_interpreters = True
+
+[testenv]
+setenv = VIRTUAL_ENV={envdir}
+         PYTHONHASHSEED=0
+         TERM=linux
+install_command =
+  pip install {opts} {packages}
+
+[testenv:py35]
+basepython = python3
+deps = -r{toxinidir}/test-requirements.txt
+commands = ostestr {posargs}
+
+[testenv:py36]
+basepython = python3.6
+deps = -r{toxinidir}/test-requirements.txt
+commands = ostestr {posargs}
+
+[testenv:pep8]
+basepython = python3
+deps = -r{toxinidir}/test-requirements.txt
+commands = flake8 {posargs}
+
+[testenv:cover]
+# Technique based heavily upon
+# https://github.com/openstack/nova/blob/master/tox.ini
+basepython = python3
+deps = -r{toxinidir}/test-requirements.txt
+setenv =
+    {[testenv]setenv}
+    PYTHON=coverage run
+commands =
+    coverage erase
+    ostestr {posargs}
+    coverage combine
+    coverage html -d cover
+    coverage xml -o cover/coverage.xml
+    coverage report
+
+[coverage:run]
+branch = True
+concurrency = multiprocessing
+parallel = True
+source =
+    .
+omit =
+    .tox/*
+    */charmhelpers/*
+    unit_tests/*
+
+[testenv:venv]
+commands = {posargs}
+
+[flake8]
+# E402 ignore necessary for path append before sys module import in actions
+ignore = E402

unit_tests/__init__.py

@@ -0,0 +1,22 @@
+# Copyright 2018 Canonical Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#  http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import sys
+
+sys.path.append('src')
+sys.path.append('src/lib')
+
+# Mock out charmhelpers so that we can test without it.
+import charms_openstack.test_mocks  # noqa
+charms_openstack.test_mocks.mock_charmhelpers()

unit_tests/test_provides.py

@@ -0,0 +1,110 @@
+# Copyright 2018 Canonical Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#  http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+import mock
+import unittest
+
+import provides
+
+
+_hook_args = {}
+
+
+def mock_hook(*args, **kwargs):
+
+    def inner(f):
+        # remember what we were passed.  Note that we can't actually determine
+        # the class we're attached to, as the decorator only gets the function.
+        _hook_args[f.__name__] = dict(args=args, kwargs=kwargs)
+        return f
+    return inner
+
+
+class TestCinderBackupProvides(unittest.TestCase):
+
+    @classmethod
+    def setUpClass(cls):
+        cls._patched_hook = mock.patch('charms.reactive.hook', mock_hook)
+        cls._patched_hook_started = cls._patched_hook.start()
+        # force provides to rerun the mock_hook decorator:
+        # try except is Python2/Python3 compatibility as Python3 has moved
+        # reload to importlib.
+        try:
+            reload(provides)
+        except NameError:
+            import importlib
+            importlib.reload(provides)
+
+    @classmethod
+    def tearDownClass(cls):
+        cls._patched_hook.stop()
+        cls._patched_hook_started = None
+        cls._patched_hook = None
+        # and fix any breakage we did to the module
+        try:
+            reload(provides)
+        except NameError:
+            import importlib
+            importlib.reload(provides)
+
+    def setUp(self):
+        self.cbr = provides.CinderBackupProvides('some-relation', [])
+        self._patches = {}
+        self._patches_start = {}
+
+    def tearDown(self):
+        self.cbr = None
+        for k, v in self._patches.items():
+            v.stop()
+            setattr(self, k, None)
+        self._patches = None
+        self._patches_start = None
+
+    def patch_cinder_backup_rel(self, attr, return_value=None):
+        mocked = mock.patch.object(self.cbr, attr)
+        self._patches[attr] = mocked
+        started = mocked.start()
+        started.return_value = return_value
+        self._patches_start[attr] = started
+        setattr(self, attr, started)
+
+    def patch_topublish(self):
+        self.patch_cinder_backup_rel('_relations')
+        relation = mock.MagicMock()
+        to_publish = mock.PropertyMock()
+        type(relation).to_publish = to_publish
+        self._relations.__iter__.return_value = [relation]
+        return relation.to_publish
+
+    def test_registered_hooks(self):
+        # test that the hooks actually registered the relation expressions that
+        # are meaningful for this interface: this is to handle regressions.
+        # The keys are the function names that the hook attaches to.
+        hook_patterns = {
+            'joined': ('{provides:backup-backend}-relation-joined', ),
+            'changed': ('{provides:backup-backend}-relation-changed', ),
+            'departed': (
+                '{provides:backup-backend}-relation-{broken,departed}', ),
+        }
+        for k, v in _hook_args.items():
+            self.assertEqual(hook_patterns[k], v['args'])
+
+    def test_publish_backend_info(self):
+        to_publish = self.patch_topublish()
+        name = 'FAKENAME'
+        configuration = {'a': 'A', 'b': 'B'}
+        self.cbr.publish(name, configuration)
+        to_publish.__setitem__.assert_has_calls([
+            mock.call('backend_name', name),
+            mock.call('subordinate_configuration', configuration)
+        ])