diff --git a/modules/libjuju/tests/unit/__init__.py b/modules/libjuju/tests/unit/__init__.py
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/modules/libjuju/tests/unit/__init__.py
diff --git a/modules/libjuju/tests/unit/test_client.py b/modules/libjuju/tests/unit/test_client.py
new file mode 100644
index 0000000..1d18bf9
--- /dev/null
+++ b/modules/libjuju/tests/unit/test_client.py
@@ -0,0 +1,26 @@
+"""
+Tests for generated client code
+
+"""
+
+import mock
+from juju.client import client
+
+
+def test_basics():
+    assert client.CLIENTS
+    for i in range(1, 5):  # Assert versions 1-4 in client dict
+        assert str(i) in client.CLIENTS
+
+
+def test_from_connection():
+    connection = mock.Mock()
+    connection.facades = {"Action": 2}
+    action_facade = client.ActionFacade.from_connection(connection)
+    assert action_facade
+
+
+def test_to_json():
+    uml = client.UserModelList([client.UserModel()])
+    assert uml.to_json() == ('{"user-models": [{"last-connection": null, '
+                             '"model": null}]}')
diff --git a/modules/libjuju/tests/unit/test_connection.py b/modules/libjuju/tests/unit/test_connection.py
new file mode 100644
index 0000000..0925d84
--- /dev/null
+++ b/modules/libjuju/tests/unit/test_connection.py
@@ -0,0 +1,65 @@
+import asyncio
+import json
+from collections import deque
+
+import mock
+from juju.client.connection import Connection
+from websockets.exceptions import ConnectionClosed
+
+import pytest
+
+from .. import base
+
+
+class WebsocketMock:
+    def __init__(self, responses):
+        super().__init__()
+        self.responses = deque(responses)
+        self.open = True
+
+    async def send(self, message):
+        pass
+
+    async def recv(self):
+        if not self.responses:
+            await asyncio.sleep(1)  # delay to give test time to finish
+            raise ConnectionClosed(0, 'ran out of responses')
+        return json.dumps(self.responses.popleft())
+
+    async def close(self):
+        self.open = False
+
+
+@pytest.mark.asyncio
+async def test_out_of_order(event_loop):
+    ws = WebsocketMock([
+        {'request-id': 1},
+        {'request-id': 3},
+        {'request-id': 2},
+    ])
+    expected_responses = [
+        {'request-id': 1},
+        {'request-id': 2},
+        {'request-id': 3},
+    ]
+    minimal_facades = [{'name': 'Pinger', 'versions': [1]}]
+    con = None
+    try:
+        with \
+                mock.patch('websockets.connect', base.AsyncMock(return_value=ws)), \
+                mock.patch(
+                    'juju.client.connection.Connection.login',
+                    base.AsyncMock(return_value={'response': {
+                        'facades': minimal_facades,
+                    }}),
+                ), \
+                mock.patch('juju.client.connection.Connection._get_ssl'), \
+                mock.patch('juju.client.connection.Connection._pinger', base.AsyncMock()):
+            con = await Connection.connect('0.1.2.3:999')
+        actual_responses = []
+        for i in range(3):
+            actual_responses.append(await con.rpc({'version': 1}))
+        assert actual_responses == expected_responses
+    finally:
+        if con:
+            await con.close()
diff --git a/modules/libjuju/tests/unit/test_constraints.py b/modules/libjuju/tests/unit/test_constraints.py
new file mode 100644
index 0000000..3c52090
--- /dev/null
+++ b/modules/libjuju/tests/unit/test_constraints.py
@@ -0,0 +1,57 @@
+#
+# Test our constraints parser
+#
+
+import unittest
+
+from juju import constraints
+
+
+class TestConstraints(unittest.TestCase):
+
+    def test_mem_regex(self):
+        m = constraints.MEM
+        self.assertTrue(m.match("10G"))
+        self.assertTrue(m.match("1G"))
+        self.assertFalse(m.match("1Gb"))
+        self.assertFalse(m.match("a1G"))
+        self.assertFalse(m.match("1000"))
+
+    def test_normalize_key(self):
+        _ = constraints.normalize_key
+
+        self.assertEqual(_("test-key"), "test_key")
+        self.assertEqual(_("test-key  "), "test_key")
+        self.assertEqual(_("  test-key"), "test_key")
+        self.assertEqual(_("TestKey"), "test_key")
+        self.assertEqual(_("testKey"), "test_key")
+
+    def test_normalize_val(self):
+        _ = constraints.normalize_value
+
+        self.assertEqual(_("10G"), 10 * 1024)
+        self.assertEqual(_("10M"), 10)
+        self.assertEqual(_("10"), 10)
+        self.assertEqual(_("foo,bar"), "foo,bar")
+
+    def test_normalize_list_val(self):
+        _ = constraints.normalize_list_value
+
+        self.assertEqual(_("foo"), ["foo"])
+        self.assertEqual(_("foo,bar"), ["foo", "bar"])
+
+    def test_parse_constraints(self):
+        _ = constraints.parse
+
+        self.assertEqual(
+            _("mem=10G"),
+            {"mem": 10 * 1024}
+        )
+
+        self.assertEqual(
+            _("mem=10G foo=bar,baz tags=tag1 spaces=space1,space2"),
+            {"mem": 10 * 1024,
+             "foo": "bar,baz",
+             "tags": ["tag1"],
+             "spaces": ["space1", "space2"]}
+        )
diff --git a/modules/libjuju/tests/unit/test_controller.py b/modules/libjuju/tests/unit/test_controller.py
new file mode 100644
index 0000000..b95b5ee
--- /dev/null
+++ b/modules/libjuju/tests/unit/test_controller.py
@@ -0,0 +1,140 @@
+import asynctest
+import mock
+from pathlib import Path
+from tempfile import NamedTemporaryFile
+
+from juju.controller import Controller
+from juju.client import client
+
+from .. import base
+
+
+class TestControllerConnect(asynctest.TestCase):
+    @asynctest.patch('juju.client.connector.Connector.connect_controller')
+    async def test_no_args(self, mock_connect_controller):
+        c = Controller()
+        await c.connect()
+        mock_connect_controller.assert_called_once_with(None)
+
+    @asynctest.patch('juju.client.connector.Connector.connect_controller')
+    async def test_with_controller_name(self, mock_connect_controller):
+        c = Controller()
+        await c.connect(controller_name='foo')
+        mock_connect_controller.assert_called_once_with('foo')
+
+    @asynctest.patch('juju.client.connector.Connector.connect')
+    async def test_with_endpoint_and_no_auth(self, mock_connect):
+        c = Controller()
+        with self.assertRaises(TypeError):
+            await c.connect(endpoint='0.1.2.3:4566')
+        self.assertEqual(mock_connect.call_count, 0)
+
+    @asynctest.patch('juju.client.connector.Connector.connect')
+    async def test_with_endpoint_and_userpass(self, mock_connect):
+        c = Controller()
+        with self.assertRaises(TypeError):
+            await c.connect(endpoint='0.1.2.3:4566', username='dummy')
+        await c.connect(endpoint='0.1.2.3:4566',
+                        username='user',
+                        password='pass')
+        mock_connect.assert_called_once_with(endpoint='0.1.2.3:4566',
+                                             username='user',
+                                             password='pass')
+
+    @asynctest.patch('juju.client.connector.Connector.connect')
+    async def test_with_endpoint_and_bakery_client(self, mock_connect):
+        c = Controller()
+        await c.connect(endpoint='0.1.2.3:4566', bakery_client='bakery')
+        mock_connect.assert_called_once_with(endpoint='0.1.2.3:4566',
+                                             bakery_client='bakery')
+
+    @asynctest.patch('juju.client.connector.Connector.connect')
+    async def test_with_endpoint_and_macaroons(self, mock_connect):
+        c = Controller()
+        await c.connect(endpoint='0.1.2.3:4566',
+                        macaroons=['macaroon'])
+        mock_connect.assert_called_with(endpoint='0.1.2.3:4566',
+                                        macaroons=['macaroon'])
+        await c.connect(endpoint='0.1.2.3:4566',
+                        bakery_client='bakery',
+                        macaroons=['macaroon'])
+        mock_connect.assert_called_with(endpoint='0.1.2.3:4566',
+                                        bakery_client='bakery',
+                                        macaroons=['macaroon'])
+
+    @asynctest.patch('juju.client.connector.Connector.connect_controller')
+    @asynctest.patch('juju.client.connector.Connector.connect')
+    async def test_with_posargs(self, mock_connect, mock_connect_controller):
+        c = Controller()
+        await c.connect('foo')
+        mock_connect_controller.assert_called_once_with('foo')
+        with self.assertRaises(TypeError):
+            await c.connect('endpoint', 'user')
+        await c.connect('endpoint', 'user', 'pass')
+        mock_connect.assert_called_once_with(endpoint='endpoint',
+                                             username='user',
+                                             password='pass')
+        await c.connect('endpoint', 'user', 'pass', 'cacert', 'bakery',
+                        'macaroons', 'loop', 'max_frame_size')
+        mock_connect.assert_called_with(endpoint='endpoint',
+                                        username='user',
+                                        password='pass',
+                                        cacert='cacert',
+                                        bakery_client='bakery',
+                                        macaroons='macaroons',
+                                        loop='loop',
+                                        max_frame_size='max_frame_size')
+
+    @asynctest.patch('juju.client.client.CloudFacade')
+    async def test_file_cred_v2(self, mock_cf):
+        with NamedTemporaryFile() as tempfile:
+            tempfile.close()
+            temppath = Path(tempfile.name)
+            temppath.write_text('cred-test')
+            cred = client.CloudCredential(auth_type='jsonfile',
+                                          attrs={'file': tempfile.name})
+            jujudata = mock.MagicMock()
+            c = Controller(jujudata=jujudata)
+            c._connector = base.AsyncMock()
+            up_creds = base.AsyncMock()
+            cloud_facade = mock_cf.from_connection()
+            cloud_facade.version = 2
+            cloud_facade.UpdateCredentials = up_creds
+            await c.add_credential(
+                name='name',
+                credential=cred,
+                cloud='cloud',
+                owner='owner',
+            )
+            assert up_creds.called
+            new_cred = up_creds.call_args[0][0][0].credential
+            assert cred.attrs['file'] == tempfile.name
+            assert new_cred.attrs['file'] == 'cred-test'
+
+    @asynctest.patch('juju.client.client.CloudFacade')
+    async def test_file_cred_v3(self, mock_cf):
+        with NamedTemporaryFile() as tempfile:
+            tempfile.close()
+            temppath = Path(tempfile.name)
+            temppath.write_text('cred-test')
+            cred = client.CloudCredential(auth_type='jsonfile',
+                                          attrs={'file': tempfile.name})
+            jujudata = mock.MagicMock()
+            c = Controller(jujudata=jujudata)
+            c._connector = base.AsyncMock()
+            up_creds = base.AsyncMock()
+            cloud_facade = mock_cf.from_connection()
+            cloud_facade.version = 3
+            cloud_facade.UpdateCredentialsCheckModels = up_creds
+            await c.add_credential(
+                name='name',
+                credential=cred,
+                cloud='cloud',
+                owner='owner',
+                force=True,
+            )
+            assert up_creds.called
+            assert up_creds.call_args[1]['force']
+            new_cred = up_creds.call_args[1]['credentials'][0].credential
+            assert cred.attrs['file'] == tempfile.name
+            assert new_cred.attrs['file'] == 'cred-test'
diff --git a/modules/libjuju/tests/unit/test_gocookies.py b/modules/libjuju/tests/unit/test_gocookies.py
new file mode 100644
index 0000000..033a0e9
--- /dev/null
+++ b/modules/libjuju/tests/unit/test_gocookies.py
@@ -0,0 +1,244 @@
+"""
+Tests for the gocookies code.
+"""
+import os
+import shutil
+import tempfile
+import unittest
+import urllib.request
+
+import pyrfc3339
+from juju.client.gocookies import GoCookieJar
+
+# cookie_content holds the JSON contents of a Go-produced
+# cookie file (reformatted so it's not all on one line but
+# otherwise unchanged).
+cookie_content = """
+[
+    {
+        "CanonicalHost": "bar.com",
+        "Creation": "2017-11-17T08:53:55.088820092Z",
+        "Domain": "bar.com",
+        "Expires": "2345-11-15T18:16:08Z",
+        "HostOnly": true,
+        "HttpOnly": false,
+        "LastAccess": "2017-11-17T08:53:55.088822562Z",
+        "Name": "bar",
+        "Path": "/",
+        "Persistent": true,
+        "Secure": false,
+        "Updated": "2017-11-17T08:53:55.088822562Z",
+        "Value": "bar-value"
+    },
+    {
+        "CanonicalHost": "x.foo.com",
+        "Creation": "2017-11-17T08:53:55.088814857Z",
+        "Domain": "x.foo.com",
+        "Expires": "2345-11-15T18:16:05Z",
+        "HostOnly": true,
+        "HttpOnly": false,
+        "LastAccess": "2017-11-17T08:53:55.088884015Z",
+        "Name": "foo",
+        "Path": "/path",
+        "Persistent": true,
+        "Secure": false,
+        "Updated": "2017-11-17T08:53:55.088814857Z",
+        "Value": "foo-path-value"
+    },
+    {
+        "CanonicalHost": "x.foo.com",
+        "Creation": "2017-11-17T08:53:55.088814857Z",
+        "Domain": "foo.com",
+        "Expires": "2345-11-15T18:16:06Z",
+        "HostOnly": false,
+        "HttpOnly": false,
+        "LastAccess": "2017-11-17T08:53:55.088919437Z",
+        "Name": "foo4",
+        "Path": "/path",
+        "Persistent": true,
+        "Secure": false,
+        "Updated": "2017-11-17T08:53:55.088814857Z",
+        "Value": "foo4-value"
+    },
+    {
+        "CanonicalHost": "x.foo.com",
+        "Creation": "2017-11-17T08:53:55.088790709Z",
+        "Domain": "x.foo.com",
+        "Expires": "2345-11-15T18:16:01Z",
+        "HostOnly": true,
+        "HttpOnly": false,
+        "LastAccess": "2017-11-17T08:53:55.088884015Z",
+        "Name": "foo",
+        "Path": "/",
+        "Persistent": true,
+        "Secure": false,
+        "Updated": "2017-11-17T08:53:55.088790709Z",
+        "Value": "foo-value"
+    },
+    {
+        "CanonicalHost": "x.foo.com",
+        "Creation": "2017-11-17T08:53:55.088790709Z",
+        "Domain": "foo.com",
+        "Expires": "2345-11-15T18:16:02Z",
+        "HostOnly": false,
+        "HttpOnly": false,
+        "LastAccess": "2017-11-17T08:53:55.088919437Z",
+        "Name": "foo1",
+        "Path": "/",
+        "Persistent": true,
+        "Secure": false,
+        "Updated": "2017-11-17T08:53:55.088790709Z",
+        "Value": "foo1-value"
+    },
+    {
+        "CanonicalHost": "x.foo.com",
+        "Creation": "2017-11-17T08:53:55.088790709Z",
+        "Domain": "x.foo.com",
+        "Expires": "2345-11-15T18:16:03Z",
+        "HostOnly": true,
+        "HttpOnly": false,
+        "LastAccess": "2017-11-17T08:53:55.088850252Z",
+        "Name": "foo2",
+        "Path": "/",
+        "Persistent": true,
+        "Secure": true,
+        "Updated": "2017-11-17T08:53:55.088790709Z",
+        "Value": "foo2-value"
+    },
+    {
+        "CanonicalHost": "x.foo.com",
+        "Creation": "2017-11-17T08:53:55.088790709Z",
+        "Domain": "foo.com",
+        "Expires": "2345-11-15T18:16:04Z",
+        "HostOnly": false,
+        "HttpOnly": false,
+        "LastAccess": "2017-11-17T08:53:55.088919437Z",
+        "Name": "foo3",
+        "Path": "/",
+        "Persistent": true,
+        "Secure": false,
+        "Updated": "2017-11-17T08:53:55.088790709Z",
+        "Value": "foo3-value"
+    }
+]
+"""
+
+# cookie_content_queries holds a set of queries
+# that were automatically generated by running
+# the queries on the above cookie_content data
+# and printing the results.
+cookie_content_queries = [
+    ('http://x.foo.com', [
+        ('foo', 'foo-value'),
+        ('foo1', 'foo1-value'),
+        ('foo3', 'foo3-value'),
+    ]),
+    ('https://x.foo.com', [
+        ('foo', 'foo-value'),
+        ('foo1', 'foo1-value'),
+        ('foo2', 'foo2-value'),
+        ('foo3', 'foo3-value'),
+    ]),
+    ('http://arble.foo.com', [
+        ('foo1', 'foo1-value'),
+        ('foo3', 'foo3-value'),
+    ]),
+    ('http://arble.com', [
+    ]),
+    ('http://x.foo.com/path/x', [
+        ('foo', 'foo-path-value'),
+        ('foo4', 'foo4-value'),
+        ('foo', 'foo-value'),
+        ('foo1', 'foo1-value'),
+        ('foo3', 'foo3-value'),
+    ]),
+    ('http://arble.foo.com/path/x', [
+        ('foo4', 'foo4-value'),
+        ('foo1', 'foo1-value'),
+        ('foo3', 'foo3-value'),
+    ]),
+    ('http://foo.com/path/x', [
+        ('foo4', 'foo4-value'),
+        ('foo1', 'foo1-value'),
+        ('foo3', 'foo3-value'),
+    ]),
+]
+
+
+class TestGoCookieJar(unittest.TestCase):
+    def setUp(self):
+        self.dir = tempfile.mkdtemp()
+
+    def tearDown(self):
+        shutil.rmtree(self.dir)
+
+    def test_readcookies(self):
+        jar = self.load_jar(cookie_content)
+        self.assert_jar_queries(jar, cookie_content_queries)
+
+    def test_roundtrip(self):
+        jar = self.load_jar(cookie_content)
+        filename2 = os.path.join(self.dir, 'cookies2')
+        jar.save(filename=filename2)
+        jar = GoCookieJar()
+        jar.load(filename=filename2)
+        self.assert_jar_queries(jar, cookie_content_queries)
+
+    def test_expiry_time(self):
+        content = '''[
+            {
+                "CanonicalHost": "bar.com",
+                "Creation": "2017-11-17T08:53:55.088820092Z",
+                "Domain": "bar.com",
+                "Expires": "2345-11-15T18:16:08Z",
+                "HostOnly": true,
+                "HttpOnly": false,
+                "LastAccess": "2017-11-17T08:53:55.088822562Z",
+                "Name": "bar",
+                "Path": "/",
+                "Persistent": true,
+                "Secure": false,
+                "Updated": "2017-11-17T08:53:55.088822562Z",
+                "Value": "bar-value"
+            }
+        ]'''
+        jar = self.load_jar(content)
+        got_expires = tuple(jar)[0].expires
+        want_expires = int(pyrfc3339.parse('2345-11-15T18:16:08Z').timestamp())
+        self.assertEqual(got_expires, want_expires)
+
+    def load_jar(self, content):
+        filename = os.path.join(self.dir, 'cookies')
+        with open(filename, 'x') as f:
+            f.write(content)
+        jar = GoCookieJar()
+        jar.load(filename=filename)
+        return jar
+
+    def assert_jar_queries(self, jar, queries):
+        '''Assert that all the given queries (see cookie_content_queries)
+        are satisfied when run on the given cookie jar.
+        :param jar CookieJar: the cookie jar to query
+        :param queries: the queries to run.
+        '''
+        for url, want_cookies in queries:
+            req = urllib.request.Request(url)
+            jar.add_cookie_header(req)
+            # We can't use SimpleCookie to find out what cookies
+            # have been presented, because SimpleCookie
+            # only allows one cookie with a given name,
+            # so we naively parse the cookies ourselves, which
+            # is OK because we know we don't have to deal
+            # with any complex cases.
+
+            cookie_header = req.get_header('Cookie')
+            got_cookies = []
+            if cookie_header is not None:
+                got_cookies = [
+                    tuple(part.split('='))
+                    for part in cookie_header.split('; ')
+                ]
+                got_cookies.sort()
+            want_cookies = list(want_cookies)
+            want_cookies.sort()
+            self.assertEqual(got_cookies, want_cookies, msg='query {}; got {}; want {}'.format(url, got_cookies, want_cookies))
diff --git a/modules/libjuju/tests/unit/test_loop.py b/modules/libjuju/tests/unit/test_loop.py
new file mode 100644
index 0000000..9043df6
--- /dev/null
+++ b/modules/libjuju/tests/unit/test_loop.py
@@ -0,0 +1,32 @@
+import asyncio
+import unittest
+
+import juju.loop
+
+
+class TestLoop(unittest.TestCase):
+    def setUp(self):
+        # new event loop for each test
+        policy = asyncio.get_event_loop_policy()
+        self.loop = policy.new_event_loop()
+        policy.set_event_loop(self.loop)
+
+    def tearDown(self):
+        self.loop.close()
+
+    def test_run(self):
+        assert asyncio.get_event_loop() == self.loop
+
+        async def _test():
+            return 'success'
+        self.assertEqual(juju.loop.run(_test()), 'success')
+
+    def test_run_interrupt(self):
+        async def _test():
+            juju.loop.run._sigint = True
+        self.assertRaises(KeyboardInterrupt, juju.loop.run, _test())
+
+    def test_run_exception(self):
+        async def _test():
+            raise ValueError()
+        self.assertRaises(ValueError, juju.loop.run, _test())
diff --git a/modules/libjuju/tests/unit/test_model.py b/modules/libjuju/tests/unit/test_model.py
new file mode 100644
index 0000000..2753d85
--- /dev/null
+++ b/modules/libjuju/tests/unit/test_model.py
@@ -0,0 +1,264 @@
+import unittest
+
+import mock
+
+import asynctest
+
+from juju.client.jujudata import FileJujuData
+from juju.model import Model
+
+
+def _make_delta(entity, type_, data=None):
+    from juju.client.client import Delta
+    from juju.delta import get_entity_delta
+
+    delta = Delta([entity, type_, data])
+    return get_entity_delta(delta)
+
+
+class TestObserver(unittest.TestCase):
+    def _make_observer(self, *args):
+        from juju.model import _Observer
+        return _Observer(*args)
+
+    def test_cares_about_id(self):
+        id_ = 'foo'
+
+        o = self._make_observer(
+            None, None, None, id_, None)
+
+        delta = _make_delta(
+            'application', 'change', dict(name=id_))
+
+        self.assertTrue(o.cares_about(delta))
+
+    def test_cares_about_type(self):
+        type_ = 'application'
+
+        o = self._make_observer(
+            None, type_, None, None, None)
+
+        delta = _make_delta(
+            type_, 'change', dict(name='foo'))
+
+        self.assertTrue(o.cares_about(delta))
+
+    def test_cares_about_action(self):
+        action = 'change'
+
+        o = self._make_observer(
+            None, None, action, None, None)
+
+        delta = _make_delta(
+            'application', action, dict(name='foo'))
+
+        self.assertTrue(o.cares_about(delta))
+
+    def test_cares_about_predicate(self):
+        def predicate(delta):
+            return delta.data.get('fizz') == 'bang'
+
+        o = self._make_observer(
+            None, None, None, None, predicate)
+
+        delta = _make_delta(
+            'application', 'change', dict(fizz='bang'))
+
+        self.assertTrue(o.cares_about(delta))
+
+
+class TestModelState(unittest.TestCase):
+    def test_apply_delta(self):
+        from juju.model import Model
+        from juju.application import Application
+
+        model = Model()
+        model._connector = mock.MagicMock()
+        delta = _make_delta('application', 'add', dict(name='foo'))
+
+        # test add
+        prev, new = model.state.apply_delta(delta)
+        self.assertEqual(
+            len(model.state.state[delta.entity][delta.get_id()]), 1)
+        self.assertIsNone(prev)
+        self.assertIsInstance(new, Application)
+
+        # test remove
+        delta.type = 'remove'
+        prev, new = model.state.apply_delta(delta)
+        # length of the entity history deque is now 3:
+        # - 1 for the first delta
+        # - 1 for the second delta
+        # - 1 for the None sentinel appended after the 'remove'
+        self.assertEqual(
+            len(model.state.state[delta.entity][delta.get_id()]), 3)
+        self.assertIsInstance(new, Application)
+        # new object is falsy because its data is None
+        self.assertFalse(new)
+        self.assertIsInstance(prev, Application)
+        self.assertTrue(prev)
+
+
+def test_get_series():
+    from juju.model import Model
+    model = Model()
+    entity = {
+        'Meta': {
+            'supported-series': {
+                'SupportedSeries': [
+                    'xenial',
+                    'trusty',
+                ],
+            },
+        },
+    }
+    assert model._get_series('cs:trusty/ubuntu', entity) == 'trusty'
+    assert model._get_series('xenial/ubuntu', entity) == 'xenial'
+    assert model._get_series('~foo/xenial/ubuntu', entity) == 'xenial'
+    assert model._get_series('~foo/ubuntu', entity) == 'xenial'
+    assert model._get_series('ubuntu', entity) == 'xenial'
+    assert model._get_series('cs:ubuntu', entity) == 'xenial'
+
+
+class TestContextManager(asynctest.TestCase):
+    @asynctest.patch('juju.model.Model.disconnect')
+    @asynctest.patch('juju.model.Model.connect')
+    async def test_normal_use(self, mock_connect, mock_disconnect):
+        from juju.model import Model
+
+        async with Model() as model:
+            self.assertTrue(isinstance(model, Model))
+
+        self.assertTrue(mock_connect.called)
+        self.assertTrue(mock_disconnect.called)
+
+    @asynctest.patch('juju.model.Model.disconnect')
+    @asynctest.patch('juju.model.Model.connect')
+    async def test_exception(self, mock_connect, mock_disconnect):
+        from juju.model import Model
+
+        class SomeException(Exception):
+            pass
+
+        with self.assertRaises(SomeException):
+            async with Model():
+                raise SomeException()
+
+        self.assertTrue(mock_connect.called)
+        self.assertTrue(mock_disconnect.called)
+
+    async def test_no_current_connection(self):
+        from juju.model import Model
+        from juju.errors import JujuConnectionError
+
+        class NoControllerJujuData(FileJujuData):
+            def current_controller(self):
+                return ""
+
+        with self.assertRaises(JujuConnectionError):
+            async with Model(jujudata=NoControllerJujuData()):
+                pass
+
+
+@asynctest.patch('juju.model.Model._after_connect')
+class TestModelConnect(asynctest.TestCase):
+    @asynctest.patch('juju.client.connector.Connector.connect_model')
+    async def test_no_args(self, mock_connect_model, _):
+        m = Model()
+        await m.connect()
+        mock_connect_model.assert_called_once_with(None)
+
+    @asynctest.patch('juju.client.connector.Connector.connect_model')
+    async def test_with_model_name(self, mock_connect_model, _):
+        m = Model()
+        await m.connect(model_name='foo')
+        mock_connect_model.assert_called_once_with('foo')
+
+    @asynctest.patch('juju.client.connector.Connector.connect_model')
+    async def test_with_endpoint_but_no_uuid(self, mock_connect_model, _):
+        m = Model()
+        with self.assertRaises(TypeError):
+            await m.connect(endpoint='0.1.2.3:4566')
+        self.assertEqual(mock_connect_model.call_count, 0)
+
+    @asynctest.patch('juju.client.connector.Connector.connect')
+    async def test_with_endpoint_and_uuid_no_auth(self, mock_connect, _):
+        m = Model()
+        with self.assertRaises(TypeError):
+            await m.connect(endpoint='0.1.2.3:4566', uuid='some-uuid')
+        self.assertEqual(mock_connect.call_count, 0)
+
+    @asynctest.patch('juju.client.connector.Connector.connect')
+    async def test_with_endpoint_and_uuid_with_userpass(self, mock_connect, _):
+        m = Model()
+        with self.assertRaises(TypeError):
+            await m.connect(endpoint='0.1.2.3:4566',
+                            uuid='some-uuid',
+                            username='user')
+        await m.connect(endpoint='0.1.2.3:4566',
+                        uuid='some-uuid',
+                        username='user',
+                        password='pass')
+        mock_connect.assert_called_once_with(endpoint='0.1.2.3:4566',
+                                             uuid='some-uuid',
+                                             username='user',
+                                             password='pass')
+
+    @asynctest.patch('juju.client.connector.Connector.connect')
+    async def test_with_endpoint_and_uuid_with_bakery(self, mock_connect, _):
+        m = Model()
+        await m.connect(endpoint='0.1.2.3:4566',
+                        uuid='some-uuid',
+                        bakery_client='bakery')
+        mock_connect.assert_called_once_with(endpoint='0.1.2.3:4566',
+                                             uuid='some-uuid',
+                                             bakery_client='bakery')
+
+    @asynctest.patch('juju.client.connector.Connector.connect')
+    async def test_with_endpoint_and_uuid_with_macaroon(self, mock_connect, _):
+        m = Model()
+        with self.assertRaises(TypeError):
+            await m.connect(endpoint='0.1.2.3:4566',
+                            uuid='some-uuid',
+                            username='user')
+        await m.connect(endpoint='0.1.2.3:4566',
+                        uuid='some-uuid',
+                        macaroons=['macaroon'])
+        mock_connect.assert_called_with(endpoint='0.1.2.3:4566',
+                                        uuid='some-uuid',
+                                        macaroons=['macaroon'])
+        await m.connect(endpoint='0.1.2.3:4566',
+                        uuid='some-uuid',
+                        bakery_client='bakery',
+                        macaroons=['macaroon'])
+        mock_connect.assert_called_with(endpoint='0.1.2.3:4566',
+                                        uuid='some-uuid',
+                                        bakery_client='bakery',
+                                        macaroons=['macaroon'])
+
+    @asynctest.patch('juju.client.connector.Connector.connect_model')
+    @asynctest.patch('juju.client.connector.Connector.connect')
+    async def test_with_posargs(self, mock_connect, mock_connect_model, _):
+        m = Model()
+        await m.connect('foo')
+        mock_connect_model.assert_called_once_with('foo')
+        with self.assertRaises(TypeError):
+            await m.connect('endpoint', 'uuid')
+        with self.assertRaises(TypeError):
+            await m.connect('endpoint', 'uuid', 'user')
+        await m.connect('endpoint', 'uuid', 'user', 'pass')
+        mock_connect.assert_called_once_with(endpoint='endpoint',
+                                             uuid='uuid',
+                                             username='user',
+                                             password='pass')
+        await m.connect('endpoint', 'uuid', 'user', 'pass', 'cacert', 'bakery',
+                        'macaroons', 'loop', 'max_frame_size')
+        mock_connect.assert_called_with(endpoint='endpoint',
+                                        uuid='uuid',
+                                        username='user',
+                                        password='pass',
+                                        cacert='cacert',
+                                        bakery_client='bakery',
+                                        macaroons='macaroons',
+                                        loop='loop',
+                                        max_frame_size='max_frame_size')
diff --git a/modules/libjuju/tests/unit/test_overrides.py b/modules/libjuju/tests/unit/test_overrides.py
new file mode 100644
index 0000000..a5835ff
--- /dev/null
+++ b/modules/libjuju/tests/unit/test_overrides.py
@@ -0,0 +1,76 @@
+from juju.client.overrides import Binary, Number  # noqa
+
+import pytest
+
+
+# test cases ported from:
+# https://github.com/juju/version/blob/master/version_test.go
+@pytest.mark.parametrize("input,expected", (
+    (None, Number(major=0, minor=0, patch=0, tag='', build=0)),
+    (Number(major=1, minor=0, patch=0), Number(major=1, minor=0, patch=0)),
+    ({'major': 1, 'minor': 0, 'patch': 0}, Number(major=1, minor=0, patch=0)),
+    ("0.0.1", Number(major=0, minor=0, patch=1)),
+    ("0.0.2", Number(major=0, minor=0, patch=2)),
+    ("0.1.0", Number(major=0, minor=1, patch=0)),
+    ("0.2.3", Number(major=0, minor=2, patch=3)),
+    ("1.0.0", Number(major=1, minor=0, patch=0)),
+    ("10.234.3456", Number(major=10, minor=234, patch=3456)),
+    ("10.234.3456.1", Number(major=10, minor=234, patch=3456, build=1)),
+    ("10.234.3456.64", Number(major=10, minor=234, patch=3456, build=64)),
+    ("10.235.3456", Number(major=10, minor=235, patch=3456)),
+    ("1.21-alpha1", Number(major=1, minor=21, patch=1, tag="alpha")),
+    ("1.21-alpha1.1", Number(major=1, minor=21, patch=1, tag="alpha",
+                             build=1)),
+    ("1.21-alpha10", Number(major=1, minor=21, patch=10, tag="alpha")),
+    ("1.21.0", Number(major=1, minor=21)),
+    ("1234567890.2.1", TypeError),
+    ("0.2..1", TypeError),
+    ("1.21.alpha1", TypeError),
+    ("1.21-alpha", TypeError),
+    ("1.21-alpha1beta", TypeError),
+    ("1.21-alpha-dev", TypeError),
+    ("1.21-alpha_dev3", TypeError),
+    ("1.21-alpha123dev3", TypeError),
+))
+def test_number(input, expected):
+    if expected is TypeError:
+        with pytest.raises(expected):
+            Number.from_json(input)
+    else:
+        result = Number.from_json(input)
+        assert result == expected
+        if isinstance(input, str):
+            assert result.to_json() == input
+
+
+# test cases ported from:
+# https://github.com/juju/version/blob/master/version_test.go
+@pytest.mark.parametrize("input,expected", (
+    (None, Binary(Number(), None, None)),
+    (Binary(Number(1), 'trusty', 'amd64'), Binary(Number(1),
+                                                  'trusty', 'amd64')),
+    ({'number': {'major': 1},
+      'series': 'trusty',
+      'arch': 'amd64'}, Binary(Number(1), 'trusty', 'amd64')),
+    ("1.2.3-trusty-amd64", Binary(Number(1, 2, 3, "", 0),
+                                  "trusty", "amd64")),
+    ("1.2.3.4-trusty-amd64", Binary(Number(1, 2, 3, "", 4),
+                                    "trusty", "amd64")),
+    ("1.2-alpha3-trusty-amd64", Binary(Number(1, 2, 3, "alpha", 0),
+                                       "trusty", "amd64")),
+    ("1.2-alpha3.4-trusty-amd64", Binary(Number(1, 2, 3, "alpha", 4),
+                                         "trusty", "amd64")),
+    ("1.2.3", TypeError),
+    ("1.2-beta1", TypeError),
+    ("1.2.3--amd64", TypeError),
+    ("1.2.3-trusty-", TypeError),
+))
+def test_binary(input, expected):
+    if expected is TypeError:
+        with pytest.raises(expected):
+            Binary.from_json(input)
+    else:
+        result = Binary.from_json(input)
+        assert result == expected
+        if isinstance(input, str):
+            assert result.to_json() == input
diff --git a/modules/libjuju/tests/unit/test_placement.py b/modules/libjuju/tests/unit/test_placement.py
new file mode 100644
index 0000000..5a933ec
--- /dev/null
+++ b/modules/libjuju/tests/unit/test_placement.py
@@ -0,0 +1,20 @@
+#
+# Test our placement helper
+#
+
+import unittest
+
+from juju import placement
+
+
+class TestPlacement(unittest.TestCase):
+
+    def test_parse_both_specified(self):
+        res = placement.parse("foo:bar")
+        self.assertEqual(res[0].scope, "foo")
+        self.assertEqual(res[0].directive, "bar")
+
+    def test_parse_machine(self):
+        res = placement.parse("22")
+        self.assertEqual(res[0].scope, "#")
+        self.assertEqual(res[0].directive, "22")
diff --git a/modules/libjuju/tests/unit/test_registration_string.py b/modules/libjuju/tests/unit/test_registration_string.py
new file mode 100644
index 0000000..f4fea44
--- /dev/null
+++ b/modules/libjuju/tests/unit/test_registration_string.py
@@ -0,0 +1,18 @@
+#
+# Test our placement helper
+#
+
+import unittest
+
+from juju.utils import generate_user_controller_access_token
+
+
+class TestRegistrationString(unittest.TestCase):
+    def test_generate_user_controller_access_token(self):
+        controller_name = "localhost-localhost"
+        endpoints = ["192.168.1.1:17070", "192.168.1.2:17070", "192.168.1.3:17070"]
+        username = "test-01234"
+        secret_key = "paNZrqOw51ONk1kTER6rkm4hdPcg5VgC/dzXYxtUZaM="
+        reg_string = generate_user_controller_access_token(username, endpoints, secret_key, controller_name)
+        assert reg_string == b"MH4TCnRlc3QtMDEyMzQwORMRMTkyLjE2OC4xLjE6MTcwNzATETE5Mi4xNjguMS4yOjE3MDcwExExOTIuMTY4" \
+                             b"LjEuMzoxNzA3MAQgpaNZrqOw51ONk1kTER6rkm4hdPcg5VgC_dzXYxtUZaMTE2xvY2FsaG9zdC1sb2NhbGhvc3QA"