diff --git a/.testr.conf b/.testr.conf
new file mode 100644
index 0000000..801646b
--- /dev/null
+++ b/.testr.conf
@@ -0,0 +1,8 @@
+[DEFAULT]
+test_command=OS_STDOUT_CAPTURE=${OS_STDOUT_CAPTURE:-1} \
+             OS_STDERR_CAPTURE=${OS_STDERR_CAPTURE:-1} \
+             OS_TEST_TIMEOUT=${OS_TEST_TIMEOUT:-60} \
+             ${PYTHON:-python} -m subunit.run discover -t ./ ./unit_tests $LISTOPT $IDOPTION
+
+test_id_option=--load-list $IDFILE
+test_list_option=--list
diff --git a/.zuul.yaml b/.zuul.yaml
index 23d3066..aa27651 100644
--- a/.zuul.yaml
+++ b/.zuul.yaml
@@ -1,3 +1,4 @@
 - project:
     templates:
       - python-charm-interface-jobs
+
diff --git a/test-requirements.txt b/test-requirements.txt
index 1bae0c7..4d72d9a 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -1,2 +1,7 @@
-flake8>=2.2.4,<=2.4.1
-os-testr>=0.4.1
\ No newline at end of file
+# Lint and unit test requirements
+flake8
+os-testr>=0.4.1
+charms.reactive
+mock>=1.2
+coverage>=3.6
+netifaces
diff --git a/tox.ini b/tox.ini
index da66e26..3cd4da3 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,5 @@
 [tox]
-envlist = pep8,py27,py34,py35
+envlist = pep8,py35
 skipsdist = True
 skip_missing_interpreters = True
 
@@ -10,20 +10,6 @@ install_command =
   pip install {opts} {packages}
 commands = ostestr {posargs}
 
-[testenv:py27]
-basepython = python2.7
-deps = -r{toxinidir}/test-requirements.txt
-# TODO: Need to write unit tests then remove the following command.
-# https://github.com/juju/charm-tools/issues/249
-commands = /bin/true
-
-[testenv:py34]
-basepython = python3.4
-deps = -r{toxinidir}/test-requirements.txt
-# TODO: Need to write unit tests then remove the following command.
-# https://github.com/juju/charm-tools/issues/249
-commands = /bin/true
-
 [testenv:py35]
 basepython = python3.5
 deps = -r{toxinidir}/test-requirements.txt
@@ -31,6 +17,11 @@ deps = -r{toxinidir}/test-requirements.txt
 # https://github.com/juju/charm-tools/issues/249
 commands = /bin/true
 
+[testenv:py36]
+basepython = python3.6
+deps = -r{toxinidir}/test-requirements.txt
+commands = ostestr {posargs}
+
 [testenv:pep8]
 basepython = python3
 deps = -r{toxinidir}/test-requirements.txt
diff --git a/unit_tests/__init__.py b/unit_tests/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/unit_tests/test_provides.py b/unit_tests/test_provides.py
new file mode 100644
index 0000000..0256a1f
--- /dev/null
+++ b/unit_tests/test_provides.py
@@ -0,0 +1,196 @@
+# 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 unittest
+import mock
+
+
+with mock.patch('charmhelpers.core.hookenv.metadata') as _meta:
+    _meta.return_Value = 'ss'
+    import provides
+
+_hook_args = {}
+
+TO_PATCH = [
+    'relation_set',
+]
+
+
+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 TestCephClientProvider(unittest.TestCase):
+
+    @classmethod
+    def setUpClass(cls):
+        cls._patched_hook = mock.patch('charms.reactive.when', mock_hook)
+        cls._patched_hook_started = cls._patched_hook.start()
+        # force requires 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 patch(self, method):
+        _m = mock.patch.object(self.obj, method)
+        _mock = _m.start()
+        self.addCleanup(_m.stop)
+        return _mock
+
+    def setUp(self):
+        self.cr = provides.CephClientProvider('some-relation', [])
+        self._patches = {}
+        self._patches_start = {}
+        self.obj = provides
+        for method in TO_PATCH:
+            setattr(self, method, self.patch(method))
+
+    def tearDown(self):
+        self.cr = None
+        for k, v in self._patches.items():
+            v.stop()
+            setattr(self, k, None)
+        self._patches = None
+        self._patches_start = None
+
+    def patch_kr(self, attr, return_value=None):
+        mocked = mock.patch.object(self.cr, attr)
+        self._patches[attr] = mocked
+        started = mocked.start()
+        started.return_value = return_value
+        self._patches_start[attr] = started
+        setattr(self, attr, started)
+
+    def test_registered_hooks(self):
+        # test that the decorators 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 = {
+            'data_changed': ('endpoint.{endpoint_name}.changed', ),
+            'joined': ('endpoint.{endpoint_name}.joined', ),
+            'broken': ('endpoint.{endpoint_name}.joined', ),
+        }
+        for k, v in _hook_args.items():
+            self.assertEqual(hook_patterns[k], v['args'])
+
+    def test_changed(self):
+        conv1 = mock.MagicMock()
+        conv1.get_remote.return_value = True
+        self.patch_kr('conversation', conv1)
+        self.patch_kr('set_state')
+        self.cr.changed()
+        self.set_state.assert_has_calls([
+            mock.call('{relation_name}.connected'),
+            mock.call('{relation_name}.broker_requested')])
+
+    def test_changed_no_request(self):
+        conv1 = mock.MagicMock()
+        conv1.get_remote.return_value = None
+        self.patch_kr('conversation', conv1)
+        self.patch_kr('set_state')
+        self.cr.changed()
+        self.set_state.assert_called_once_with('{relation_name}.connected')
+
+    def test_provide_auth(self):
+        conv1 = mock.MagicMock()
+        conv1.get_remote.return_value = None
+        conv1.namespace = 'ns1'
+        self.patch_kr('conversation', conv1)
+        self.cr.provide_auth(
+            'svc1',
+            'secret',
+            'ssl1.0',
+            '10.0.0.10')
+        expect = {
+            'auth': 'ssl1.0',
+            'ceph-public-address': '10.0.0.10'}
+        conv1.set_remote.assert_called_once_with(**expect)
+        self.relation_set.assert_called_once_with(
+            relation_id='ns1',
+            relation_settings={'key': 'secret'})
+
+    def test_requested_keys(self):
+        conv1 = mock.MagicMock()
+        conv1.scope = 'svc1'
+        conv2 = mock.MagicMock()
+        conv2.scope = 'svc2'
+        self.patch_kr('conversations', [conv1, conv2])
+        self.patch_kr('requested_key')
+        keys = {
+            'svc1': 'key'}
+        self.requested_key.side_effect = lambda x: keys.get(x)
+        self.assertEqual(
+            list(self.cr.requested_keys()),
+            ['svc2'])
+
+    def test_requested_key(self):
+        conv1 = mock.MagicMock()
+        self.patch_kr('conversation', conv1)
+        self.cr.requested_key('svc1')
+        self.conversation.assert_called_once_with(scope='svc1')
+        self.conversation(scope='svc1').get_remote.assert_called_once_with(
+            'key')
+
+    def test_provide_broker_token(self):
+        conv1 = mock.MagicMock()
+        self.patch_kr('conversation', conv1)
+        self.cr.provide_broker_token('svc1', 'urkey', 'token1')
+        conv1.set_remote.assert_called_once_with(
+            broker_rsp='token1',
+            urkey='token1')
+
+    def test_requested_tokens(self):
+        conv1 = mock.MagicMock()
+        conv1.scope = 'svc1'
+        conv2 = mock.MagicMock()
+        conv2.scope = 'svc2'
+        self.patch_kr('conversations', [conv1, conv2])
+        tokens = {
+            'svc1': 'token1',
+            'svc2': 'token2'}
+        self.patch_kr('requested_token')
+        self.requested_token.side_effect = lambda x: tokens.get(x)
+        self.assertEqual(
+            list(self.cr.requested_tokens()),
+            [('svc1', 'token1'), ('svc2', 'token2')])
+
+    def test_requested_token(self):
+        conv1 = mock.MagicMock()
+        self.patch_kr('conversation', conv1)
+        self.cr.requested_token('svc1')
+        self.conversation.assert_called_once_with(scope='svc1')
+        self.conversation(scope='svc1').get_remote.assert_called_once_with(
+            'broker_req')
diff --git a/unit_tests/test_requires.py b/unit_tests/test_requires.py
new file mode 100644
index 0000000..efef604
--- /dev/null
+++ b/unit_tests/test_requires.py
@@ -0,0 +1,269 @@
+# 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 unittest
+import mock
+
+
+with mock.patch('charmhelpers.core.hookenv.metadata') as _meta:
+    _meta.return_Value = 'ss'
+    import requires
+
+import charmhelpers
+
+
+_hook_args = {}
+
+TO_PATCH = [
+    'is_request_complete',
+    'send_request_if_needed',
+]
+
+
+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 TestCephClientRequires(unittest.TestCase):
+
+    @classmethod
+    def setUpClass(cls):
+        cls._patched_hook = mock.patch('charms.reactive.when', mock_hook)
+        cls._patched_hook_started = cls._patched_hook.start()
+        # force requires to rerun the mock_hook decorator:
+        # try except is Python2/Python3 compatibility as Python3 has moved
+        # reload to importlib.
+        try:
+            reload(requires)
+        except NameError:
+            import importlib
+            importlib.reload(requires)
+
+    @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(requires)
+        except NameError:
+            import importlib
+            importlib.reload(requires)
+
+    def patch(self, method):
+        _m = mock.patch.object(self.obj, method)
+        _mock = _m.start()
+        self.addCleanup(_m.stop)
+        return _mock
+
+    def setUp(self):
+        self.cr = requires.CephClientRequires('some-relation', [])
+        self._patches = {}
+        self._patches_start = {}
+        self.obj = requires
+        for method in TO_PATCH:
+            setattr(self, method, self.patch(method))
+
+    def tearDown(self):
+        self.cr = None
+        for k, v in self._patches.items():
+            v.stop()
+            setattr(self, k, None)
+        self._patches = None
+        self._patches_start = None
+
+    def patch_kr(self, attr, return_value=None):
+        mocked = mock.patch.object(self.cr, attr)
+        self._patches[attr] = mocked
+        started = mocked.start()
+        started.return_value = return_value
+        self._patches_start[attr] = started
+        setattr(self, attr, started)
+
+    def test_registered_hooks(self):
+        # test that the decorators 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 = {
+            'data_changed': ('endpoint.{endpoint_name}.changed', ),
+            'joined': ('endpoint.{endpoint_name}.joined', ),
+            'broken': ('endpoint.{endpoint_name}.joined', ),
+        }
+        for k, v in _hook_args.items():
+            self.assertEqual(hook_patterns[k], v['args'])
+
+    def test_date_changed(self):
+        self.patch_kr('key', 'key1')
+        self.patch_kr('auth', 'auth1')
+        self.patch_kr('mon_hosts', 'host1')
+        self.patch_kr('get_local', None)
+        self.patch_kr('set_state')
+        self.cr.changed()
+        self.set_state.assert_called_once_with('{relation_name}.available')
+
+    def test_date_changed_incomplete(self):
+        self.patch_kr('key', 'key1')
+        self.patch_kr('auth', None)
+        self.patch_kr('mon_hosts', 'host1')
+        self.patch_kr('get_local', None)
+        self.patch_kr('set_state')
+        self.cr.changed()
+        self.assertFalse(self.set_state.called)
+
+    def test_date_changed_existing_broker_rq(self):
+        broker_req = (
+            '{"api-version": 1, '
+            '"request-id": "4f7e247d-f953-11e8-a4f3-fa163e55565e",'
+            '"ops": [{"group": "volumes", "name": "cinder-ceph", '
+            '"weight": 40, "replicas": 3, "pg_num": null, '
+            '"group-namespace": null, "op": "create-pool"}]}')
+        self.patch_kr('key', 'key1')
+        self.patch_kr('auth', 'auth1')
+        self.patch_kr('mon_hosts', 'host1')
+        self.patch_kr('get_local', broker_req)
+        self.patch_kr('set_state')
+        self.is_request_complete.return_value = True
+        self.cr.changed()
+        self.set_state.assert_has_calls([
+            mock.call('{relation_name}.available'),
+            mock.call('{relation_name}.pools.available')])
+
+    def test_date_changed_existing_broker_rq_incomplete(self):
+        broker_req = (
+            '{"api-version": 1, '
+            '"request-id": "4f7e247d-f953-11e8-a4f3-fa163e55565e",'
+            '"ops": [{"group": "volumes", "name": "cinder-ceph", '
+            '"weight": 40, "replicas": 3, "pg_num": null, '
+            '"group-namespace": null, "op": "create-pool"}]}')
+        self.patch_kr('key', 'key1')
+        self.patch_kr('auth', 'auth1')
+        self.patch_kr('mon_hosts', 'host1')
+        self.patch_kr('get_local', broker_req)
+        self.patch_kr('set_state')
+        self.is_request_complete.return_value = False
+        self.cr.changed()
+        # Side effect of asserting pools.available was not set.
+        self.set_state.assert_called_once_with('{relation_name}.available')
+
+    def test_broken(self):
+        self.patch_kr('remove_state')
+        self.cr.broken()
+        self.remove_state.assert_has_calls([
+            mock.call('{relation_name}.available'),
+            mock.call('{relation_name}.connected'),
+            mock.call('{relation_name}.pools.available')])
+
+    @mock.patch.object(charmhelpers.contrib.storage.linux.ceph.uuid, 'uuid1')
+    def test_create_pool_new_request(self, _uuid1):
+        _uuid1.return_value = '9e34123e-fa0c-11e8-ad9c-fa163ed1cc55'
+        req = (
+            '{"api-version": 1, '
+            '"ops": [{"op": "create-pool", "name": "bob", "replicas": 3, '
+            '"pg_num": null, "weight": null, "group": null, '
+            '"group-namespace": null}], '
+            '"request-id": "9e34123e-fa0c-11e8-ad9c-fa163ed1cc55"}')
+        self.patch_kr('get_local', None)
+        self.patch_kr('set_local')
+        self.cr.create_pool('bob')
+        self.set_local.assert_called_once_with(key='broker_req', value=req)
+        ceph_broker_rq = self.send_request_if_needed.mock_calls[0][1][0]
+        self.assertEqual(
+            ceph_broker_rq.ops,
+            [{
+                'op': 'create-pool',
+                'name': 'bob',
+                'replicas': 3,
+                'group': None,
+                'group-namespace': None,
+                'pg_num': None,
+                'weight': None}])
+
+    @mock.patch.object(charmhelpers.contrib.storage.linux.ceph.uuid, 'uuid1')
+    def test_create_pool_existing_request(self, _uuid1):
+        _uuid1.return_value = '9e34123e-fa0c-11e8-ad9c-fa163ed1cc55'
+        req = (
+            '{"api-version": 1, '
+            '"ops": [{"op": "create-pool", "name": "bob", "replicas": 3, '
+            '"pg_num": null, "weight": null, "group": null, '
+            '"group-namespace": null}], '
+            '"request-id": "9e34123e-fa0c-11e8-ad9c-fa163ed1cc55"}')
+        self.patch_kr('get_local', req)
+        self.cr.create_pool('bob')
+        ceph_broker_rq = self.send_request_if_needed.mock_calls[0][1][0]
+        self.assertEqual(
+            ceph_broker_rq.ops,
+            [{
+                'op': 'create-pool',
+                'name': 'bob',
+                'replicas': 3,
+                'group': None,
+                'group-namespace': None,
+                'pg_num': None,
+                'weight': None}])
+
+    @mock.patch.object(requires.hookenv, 'related_units')
+    @mock.patch.object(requires.hookenv, 'relation_get')
+    def test_get_remote_all(self, relation_get, related_units):
+        unit_data = {
+            'rid:1': {
+                'app1/0': {
+                    'key1': 'value1',
+                    'key2': 'value2'},
+                'app1/1': {
+                    'key1': 'value1',
+                    'key2': 'value3'}},
+            'rid:2': {
+                'app2/0': {
+                    'key1': 'value1',
+                    'key2': 'value3'}},
+            'rid:3': {}}
+
+        def get_unit_data(key, unit, relation_id):
+            return unit_data[relation_id].get(unit, {}).get(key, {})
+        conv1 = mock.MagicMock()
+        conv1.relation_ids = ['rid:1', 'rid:2']
+        conv2 = mock.MagicMock()
+        conv2.relation_ids = ['rid:3']
+        self.patch_kr('conversations', [conv1, conv2])
+        related_units.side_effect = lambda x: unit_data[x].keys()
+        relation_get.side_effect = get_unit_data
+        # Check de-duplication:
+        self.assertEqual(
+            self.cr.get_remote_all('key1'),
+            ['value1'])
+        # Check multiple values:
+        self.assertEqual(
+            self.cr.get_remote_all('key2'),
+            ['value2', 'value3'])
+        # Check missing key
+        self.assertEqual(
+            self.cr.get_remote_all('key100'),
+            [])
+        # Check missing key with default
+        self.assertEqual(
+            self.cr.get_remote_all('key100', default='defaultvalue'),
+            ['defaultvalue'])
+
+    def test_mon_hosts(self):
+        self.patch_kr('get_remote_all', ['10.0.0.10 10.0.0.12', '10.0.0.23'])
+        self.assertEqual(
+            self.cr.mon_hosts(),
+            ['10.0.0.10', '10.0.0.12', '10.0.0.23'])