Add unit tests for series selector functionality

Author: cderici

tests/unit/test_utils.py

@@ -1,7 +1,10 @@
 import unittest
+import pytest
 
-from juju.utils import juju_config_dir, juju_ssh_key_paths, parse_base_arg
+from juju.utils import series_selector, get_base_from_origin_or_channel, parse_base_arg, juju_config_dir, juju_ssh_key_paths, DEFAULT_SUPPORTED_LTS
 from juju.client import client
+from juju.errors import JujuError
+from juju.url import URL
 
 
 class TestDirResolve(unittest.TestCase):
@@ -21,3 +24,32 @@ def test_parse_base_arg(self):
         assert isinstance(base, client.Base)
         assert base.name == 'ubuntu'
         assert base.channel == '22.04'
+
+
+class TestBaseFromSeries(unittest.TestCase):
+    def test_get_base_from_series(self):
+        b = get_base_from_origin_or_channel(client.CharmOrigin(track='latest', risk='edge'), series='jammy')
+        assert b.name == 'ubuntu'
+        assert b.channel == '22.04/edge'
+
+
+class TestSeriesSelector(unittest.TestCase):
+    def test_series_arg(self):
+        assert series_selector('jammy', []) == 'jammy'
+        assert series_selector('jammy', ['jammy']) == 'jammy'
+        with pytest.raises(JujuError):
+            series_selector(series_arg='jammy', supported_series=['focal'])
+        assert series_selector(series_arg='foo', supported_series=[], force=True) == 'foo'
+
+    def test_charm_url(self):
+        assert series_selector(charm_url=URL.parse('ch:jammy/ubuntu'), supported_series=['jammy']) == 'jammy'
+
+    def test_model_config(self):
+        mconf = {'default-base': client.ConfigValue(value='ubuntu@22.04')}
+        assert series_selector(model_config=mconf, supported_series=['jammy']) == 'jammy'
+
+    def test_charm_list_series(self):
+        assert series_selector(supported_series=['focal', 'jammy']) == 'jammy'
+
+    def test_return_lts(self):
+        assert series_selector() == DEFAULT_SUPPORTED_LTS