Refactoring POL Charm to use Operator Framework

This refactoring work includes tests.

Note 1: old charm is in pol-k8s folder.
Note 2: relation-departed is currently not tested because there is
        no function to remove a relation in the Testing Harness.
        There is currently one issue open and the Charmcraft team
        should provide feedback soon.

Change-Id: Ib21779c5fc781cbb5901351ccf02ca5f9b36b181
Signed-off-by: sousaedu <eduardo.sousa@canonical.com>
diff --git a/installers/charm/pol/tests/__init__.py b/installers/charm/pol/tests/__init__.py
new file mode 100644
index 0000000..d0d973a
--- /dev/null
+++ b/installers/charm/pol/tests/__init__.py
@@ -0,0 +1,31 @@
+#!/usr/bin/env python3
+# Copyright 2020 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.
+#
+# For those usages not covered by the Apache License, Version 2.0 please
+# contact: legal@canonical.com
+#
+# To get in touch with the maintainers, please contact:
+# osm-charmers@lists.launchpad.net
+##
+
+"""Init mocking for unit tests."""
+
+import sys
+import mock
+
+sys.path.append("src")
+
+oci_image = mock.MagicMock()
+sys.modules["oci_image"] = oci_image
diff --git a/installers/charm/pol/tests/test_charm.py b/installers/charm/pol/tests/test_charm.py
new file mode 100644
index 0000000..68130fc
--- /dev/null
+++ b/installers/charm/pol/tests/test_charm.py
@@ -0,0 +1,236 @@
+#!/usr/bin/env python3
+# Copyright 2020 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.
+#
+# For those usages not covered by the Apache License, Version 2.0 please
+# contact: legal@canonical.com
+#
+# To get in touch with the maintainers, please contact:
+# osm-charmers@lists.launchpad.net
+##
+
+from typing import NoReturn
+import unittest
+from ops.model import BlockedStatus
+
+from ops.testing import Harness
+
+from charm import PolCharm
+
+
+class TestCharm(unittest.TestCase):
+    """POL Charm unit tests."""
+
+    def setUp(self) -> NoReturn:
+        """Test setup"""
+        self.harness = Harness(PolCharm)
+        self.harness.set_leader(is_leader=True)
+        self.harness.begin()
+
+    def test_on_start_without_relations(self) -> NoReturn:
+        """Test installation without any relation."""
+        self.harness.charm.on.start.emit()
+
+        # Verifying status
+        self.assertIsInstance(self.harness.charm.unit.status, BlockedStatus)
+
+        # Verifying status message
+        self.assertGreater(len(self.harness.charm.unit.status.message), 0)
+        self.assertTrue(
+            self.harness.charm.unit.status.message.startswith("Waiting for ")
+        )
+        self.assertIn("kafka", self.harness.charm.unit.status.message)
+        self.assertIn("mongodb", self.harness.charm.unit.status.message)
+        self.assertTrue(self.harness.charm.unit.status.message.endswith(" relations"))
+
+    def test_on_start_with_relations(self) -> NoReturn:
+        """Test deployment without keystone."""
+        expected_result = {
+            "version": 3,
+            "containers": [
+                {
+                    "name": "pol",
+                    "imageDetails": self.harness.charm.image.fetch(),
+                    "imagePullPolicy": "Always",
+                    "ports": [
+                        {
+                            "name": "pol",
+                            "containerPort": 80,
+                            "protocol": "TCP",
+                        }
+                    ],
+                    "envConfig": {
+                        "ALLOW_ANONYMOUS_LOGIN": "yes",
+                        "OSMPOL_GLOBAL_LOGLEVEL": "INFO",
+                        "OSMPOL_MESSAGE_HOST": "kafka",
+                        "OSMPOL_MESSAGE_DRIVER": "kafka",
+                        "OSMPOL_MESSAGE_PORT": 9092,
+                        "OSMPOL_DATABASE_DRIVER": "mongo",
+                        "OSMPOL_DATABASE_URI": "mongodb://mongo:27017",
+                    },
+                }
+            ],
+            "kubernetesResources": {"ingressResources": []},
+        }
+
+        self.harness.charm.on.start.emit()
+
+        # Check if kafka datastore is initialized
+        self.assertIsNone(self.harness.charm.state.message_host)
+        self.assertIsNone(self.harness.charm.state.message_port)
+
+        # Check if mongodb datastore is initialized
+        self.assertIsNone(self.harness.charm.state.database_uri)
+
+        # Initializing the kafka relation
+        kafka_relation_id = self.harness.add_relation("kafka", "kafka")
+        self.harness.add_relation_unit(kafka_relation_id, "kafka/0")
+        self.harness.update_relation_data(
+            kafka_relation_id, "kafka/0", {"host": "kafka", "port": 9092}
+        )
+
+        # Initializing the mongo relation
+        mongodb_relation_id = self.harness.add_relation("mongodb", "mongodb")
+        self.harness.add_relation_unit(mongodb_relation_id, "mongodb/0")
+        self.harness.update_relation_data(
+            mongodb_relation_id,
+            "mongodb/0",
+            {"connection_string": "mongodb://mongo:27017"},
+        )
+
+        # Checking if kafka data is stored
+        self.assertEqual(self.harness.charm.state.message_host, "kafka")
+        self.assertEqual(self.harness.charm.state.message_port, 9092)
+
+        # Checking if mongodb data is stored
+        self.assertEqual(self.harness.charm.state.database_uri, "mongodb://mongo:27017")
+
+        # Verifying status
+        self.assertNotIsInstance(self.harness.charm.unit.status, BlockedStatus)
+
+        pod_spec, _ = self.harness.get_pod_spec()
+
+        self.assertDictEqual(expected_result, pod_spec)
+
+    def test_on_kafka_app_relation_changed(self) -> NoReturn:
+        """Test to see if kafka relation is updated."""
+        self.harness.charm.on.start.emit()
+
+        self.assertIsNone(self.harness.charm.state.message_host)
+        self.assertIsNone(self.harness.charm.state.message_port)
+
+        relation_id = self.harness.add_relation("kafka", "kafka")
+        self.harness.add_relation_unit(relation_id, "kafka/0")
+        self.harness.update_relation_data(
+            relation_id, "kafka", {"host": "kafka", "port": 9092}
+        )
+
+        self.assertEqual(self.harness.charm.state.message_host, "kafka")
+        self.assertEqual(self.harness.charm.state.message_port, 9092)
+
+        # Verifying status
+        self.assertIsInstance(self.harness.charm.unit.status, BlockedStatus)
+
+        # Verifying status message
+        self.assertGreater(len(self.harness.charm.unit.status.message), 0)
+        self.assertTrue(
+            self.harness.charm.unit.status.message.startswith("Waiting for ")
+        )
+        self.assertNotIn("kafka", self.harness.charm.unit.status.message)
+        self.assertIn("mongodb", self.harness.charm.unit.status.message)
+        self.assertTrue(self.harness.charm.unit.status.message.endswith(" relation"))
+
+    def test_on_kafka_unit_relation_changed(self) -> NoReturn:
+        """Test to see if kafka relation is updated."""
+        self.harness.charm.on.start.emit()
+
+        self.assertIsNone(self.harness.charm.state.message_host)
+        self.assertIsNone(self.harness.charm.state.message_port)
+
+        relation_id = self.harness.add_relation("kafka", "kafka")
+        self.harness.add_relation_unit(relation_id, "kafka/0")
+        self.harness.update_relation_data(
+            relation_id, "kafka/0", {"host": "kafka", "port": 9092}
+        )
+
+        self.assertEqual(self.harness.charm.state.message_host, "kafka")
+        self.assertEqual(self.harness.charm.state.message_port, 9092)
+
+        # Verifying status
+        self.assertIsInstance(self.harness.charm.unit.status, BlockedStatus)
+
+        # Verifying status message
+        self.assertGreater(len(self.harness.charm.unit.status.message), 0)
+        self.assertTrue(
+            self.harness.charm.unit.status.message.startswith("Waiting for ")
+        )
+        self.assertNotIn("kafka", self.harness.charm.unit.status.message)
+        self.assertIn("mongodb", self.harness.charm.unit.status.message)
+        self.assertTrue(self.harness.charm.unit.status.message.endswith(" relation"))
+
+    def test_on_mongodb_app_relation_changed(self) -> NoReturn:
+        """Test to see if mongodb relation is updated."""
+        self.harness.charm.on.start.emit()
+
+        self.assertIsNone(self.harness.charm.state.database_uri)
+
+        relation_id = self.harness.add_relation("mongodb", "mongodb")
+        self.harness.add_relation_unit(relation_id, "mongodb/0")
+        self.harness.update_relation_data(
+            relation_id, "mongodb", {"connection_string": "mongodb://mongo:27017"}
+        )
+
+        self.assertEqual(self.harness.charm.state.database_uri, "mongodb://mongo:27017")
+
+        # Verifying status
+        self.assertIsInstance(self.harness.charm.unit.status, BlockedStatus)
+
+        # Verifying status message
+        self.assertGreater(len(self.harness.charm.unit.status.message), 0)
+        self.assertTrue(
+            self.harness.charm.unit.status.message.startswith("Waiting for ")
+        )
+        self.assertIn("kafka", self.harness.charm.unit.status.message)
+        self.assertNotIn("mongodb", self.harness.charm.unit.status.message)
+        self.assertTrue(self.harness.charm.unit.status.message.endswith(" relation"))
+
+    def test_on_mongodb_unit_relation_changed(self) -> NoReturn:
+        """Test to see if mongodb relation is updated."""
+        self.harness.charm.on.start.emit()
+
+        self.assertIsNone(self.harness.charm.state.database_uri)
+
+        relation_id = self.harness.add_relation("mongodb", "mongodb")
+        self.harness.add_relation_unit(relation_id, "mongodb/0")
+        self.harness.update_relation_data(
+            relation_id, "mongodb/0", {"connection_string": "mongodb://mongo:27017"}
+        )
+
+        self.assertEqual(self.harness.charm.state.database_uri, "mongodb://mongo:27017")
+
+        # Verifying status
+        self.assertIsInstance(self.harness.charm.unit.status, BlockedStatus)
+
+        # Verifying status message
+        self.assertGreater(len(self.harness.charm.unit.status.message), 0)
+        self.assertTrue(
+            self.harness.charm.unit.status.message.startswith("Waiting for ")
+        )
+        self.assertIn("kafka", self.harness.charm.unit.status.message)
+        self.assertNotIn("mongodb", self.harness.charm.unit.status.message)
+        self.assertTrue(self.harness.charm.unit.status.message.endswith(" relation"))
+
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/installers/charm/pol/tests/test_pod_spec.py b/installers/charm/pol/tests/test_pod_spec.py
new file mode 100644
index 0000000..5ca5a93
--- /dev/null
+++ b/installers/charm/pol/tests/test_pod_spec.py
@@ -0,0 +1,217 @@
+#!/usr/bin/env python3
+# Copyright 2020 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.
+#
+# For those usages not covered by the Apache License, Version 2.0 please
+# contact: legal@canonical.com
+#
+# To get in touch with the maintainers, please contact:
+# osm-charmers@lists.launchpad.net
+##
+
+from pydantic import ValidationError
+from typing import NoReturn
+import unittest
+
+import pod_spec
+
+
+class TestPodSpec(unittest.TestCase):
+    """Pod spec unit tests."""
+
+    def test_make_pod_ports(self) -> NoReturn:
+        """Testing make pod ports."""
+        port = 80
+
+        expected_result = [
+            {
+                "name": "pol",
+                "containerPort": port,
+                "protocol": "TCP",
+            }
+        ]
+
+        pod_ports = pod_spec._make_pod_ports(port)
+
+        self.assertListEqual(expected_result, pod_ports)
+
+    def test_make_pod_envconfig(self) -> NoReturn:
+        """Teting make pod envconfig."""
+        config = {
+            "log_level": "INFO",
+        }
+        relation_state = {
+            "message_host": "kafka",
+            "message_port": 9090,
+            "database_uri": "mongodb://mongo",
+        }
+
+        expected_result = {
+            "ALLOW_ANONYMOUS_LOGIN": "yes",
+            "OSMPOL_GLOBAL_LOGLEVEL": config["log_level"],
+            "OSMPOL_MESSAGE_HOST": relation_state["message_host"],
+            "OSMPOL_MESSAGE_DRIVER": "kafka",
+            "OSMPOL_MESSAGE_PORT": relation_state["message_port"],
+            "OSMPOL_DATABASE_DRIVER": "mongo",
+            "OSMPOL_DATABASE_URI": relation_state["database_uri"],
+        }
+
+        pod_envconfig = pod_spec._make_pod_envconfig(config, relation_state)
+
+        self.assertDictEqual(expected_result, pod_envconfig)
+
+    def test_make_startup_probe(self) -> NoReturn:
+        """Testing make startup probe."""
+        expected_result = {
+            "exec": {"command": ["/usr/bin/pgrep", "python3"]},
+            "initialDelaySeconds": 60,
+            "timeoutSeconds": 5,
+        }
+
+        startup_probe = pod_spec._make_startup_probe()
+
+        self.assertDictEqual(expected_result, startup_probe)
+
+    def test_make_readiness_probe(self) -> NoReturn:
+        """Testing make readiness probe."""
+        expected_result = {
+            "exec": {
+                "command": ["sh", "-c", "osm-pol-healthcheck || exit 1"],
+            },
+            "periodSeconds": 10,
+            "timeoutSeconds": 5,
+            "successThreshold": 1,
+            "failureThreshold": 3,
+        }
+
+        readiness_probe = pod_spec._make_readiness_probe()
+
+        self.assertDictEqual(expected_result, readiness_probe)
+
+    def test_make_liveness_probe(self) -> NoReturn:
+        """Testing make liveness probe."""
+        expected_result = {
+            "exec": {
+                "command": ["sh", "-c", "osm-pol-healthcheck || exit 1"],
+            },
+            "initialDelaySeconds": 45,
+            "periodSeconds": 10,
+            "timeoutSeconds": 5,
+            "successThreshold": 1,
+            "failureThreshold": 3,
+        }
+
+        liveness_probe = pod_spec._make_liveness_probe()
+
+        self.assertDictEqual(expected_result, liveness_probe)
+
+    def test_make_pod_spec(self) -> NoReturn:
+        """Testing make pod spec."""
+        image_info = {"upstream-source": "opensourcemano/pol:8"}
+        config = {
+            "log_level": "INFO",
+        }
+        relation_state = {
+            "message_host": "kafka",
+            "message_port": 9090,
+            "database_uri": "mongodb://mongo",
+        }
+        app_name = "pol"
+        port = 80
+
+        expected_result = {
+            "version": 3,
+            "containers": [
+                {
+                    "name": app_name,
+                    "imageDetails": image_info,
+                    "imagePullPolicy": "Always",
+                    "ports": [
+                        {
+                            "name": app_name,
+                            "containerPort": port,
+                            "protocol": "TCP",
+                        }
+                    ],
+                    "envConfig": {
+                        "ALLOW_ANONYMOUS_LOGIN": "yes",
+                        "OSMPOL_GLOBAL_LOGLEVEL": config["log_level"],
+                        "OSMPOL_MESSAGE_HOST": relation_state["message_host"],
+                        "OSMPOL_MESSAGE_DRIVER": "kafka",
+                        "OSMPOL_MESSAGE_PORT": relation_state["message_port"],
+                        "OSMPOL_DATABASE_DRIVER": "mongo",
+                        "OSMPOL_DATABASE_URI": relation_state["database_uri"],
+                    },
+                }
+            ],
+            "kubernetesResources": {"ingressResources": []},
+        }
+
+        spec = pod_spec.make_pod_spec(
+            image_info, config, relation_state, app_name, port
+        )
+
+        self.assertDictEqual(expected_result, spec)
+
+    def test_make_pod_spec_without_image_info(self) -> NoReturn:
+        """Testing make pod spec without image_info."""
+        image_info = None
+        config = {
+            "log_level": "INFO",
+        }
+        relation_state = {
+            "message_host": "kafka",
+            "message_port": 9090,
+            "database_uri": "mongodb://mongo",
+        }
+        app_name = "pol"
+        port = 80
+
+        spec = pod_spec.make_pod_spec(
+            image_info, config, relation_state, app_name, port
+        )
+
+        self.assertIsNone(spec)
+
+    def test_make_pod_spec_without_config(self) -> NoReturn:
+        """Testing make pod spec without config."""
+        image_info = {"upstream-source": "opensourcemano/pol:8"}
+        config = {}
+        relation_state = {
+            "message_host": "kafka",
+            "message_port": 9090,
+            "database_uri": "mongodb://mongo",
+        }
+        app_name = "pol"
+        port = 80
+
+        with self.assertRaises(ValidationError):
+            pod_spec.make_pod_spec(image_info, config, relation_state, app_name, port)
+
+    def test_make_pod_spec_without_relation_state(self) -> NoReturn:
+        """Testing make pod spec without relation_state."""
+        image_info = {"upstream-source": "opensourcemano/pol:8"}
+        config = {
+            "log_level": "INFO",
+        }
+        relation_state = {}
+        app_name = "pol"
+        port = 80
+
+        with self.assertRaises(ValidationError):
+            pod_spec.make_pod_spec(image_info, config, relation_state, app_name, port)
+
+
+if __name__ == "__main__":
+    unittest.main()