add unit tests

src/charm.py

@@ -11,7 +11,6 @@
 from pathlib import Path
 
 from typing import Set, List, Optional, Dict
-from exceptions import ApplicationHostNotFoundError
 
 from charms.mongodb.v0.mongodb_secrets import SecretCache
 from charms.mongos.v0.mongos_client_interface import MongosProvider
@@ -25,7 +24,7 @@
 from config import Config
 
 import ops
-from ops.model import BlockedStatus, MaintenanceStatus, WaitingStatus, Relation, Unit
+from ops.model import BlockedStatus, MaintenanceStatus, WaitingStatus, Relation
 from ops.charm import InstallEvent, StartEvent, RelationDepartedEvent
 
 import logging
@@ -355,7 +354,7 @@ def get_mongos_host(self) -> str:
         the client wishes to connect to mongos (inside Juju or outside).
         """
         if self.is_external_client:
-            return self._unit_ip(self.unit)
+            return self._unit_ip
         else:
             return Config.MONGOS_SOCKET_URI_FMT
 
@@ -364,20 +363,6 @@ def _generate_relation_departed_key(rel_id: int) -> str:
         """Generates the relation departed key for a specified relation id."""
         return f"relation_{rel_id}_departed"
 
-    def _unit_ip(self, unit: Unit) -> str:
-        """Returns the ip address of a given unit."""
-        # check if host is current host
-        if unit == self.unit:
-            return str(
-                self.model.get_binding(Config.Relations.PEERS).network.bind_address
-            )
-        # check if host is a peer
-        elif unit in self._peers.data:
-            return str(self._peers.data[unit].get("private-address"))
-        # raise exception if host not found
-        else:
-            raise ApplicationHostNotFoundError
-
     def open_mongos_port():
         try:
             logger.debug("opening tcp port")
@@ -389,6 +374,11 @@ def open_mongos_port():
     # END: helper functions
 
     # BEGIN: properties
+    @property
+    def _unit_ip(self) -> str:
+        """Returns the ip address of the unit."""
+        return str(self.model.get_binding(Config.Relations.PEERS).network.bind_address)
+
     @property
     def is_external_client(self) -> Optional[str]:
         """Returns the database requested by the hosting application of the subordinate charm."""

tests/unit/test_charm.py

@@ -22,6 +22,9 @@
 from charms.data_platform_libs.v0.data_interfaces import DatabaseRequiresEvents
 
 CLUSTER_ALIAS = "cluster"
+MONGOS_SOCKET_URI_FMT = (
+    "%2Fvar%2Fsnap%2Fcharmed-mongodb%2Fcommon%2Fvar%2Fmongodb-27018.sock"
+)
 
 
 class TestCharm(unittest.TestCase):
@@ -143,3 +146,14 @@ def test_status_shows_mongos_waiting(self):
         self.harness.add_relation("cluster", "config-server")
         self.harness.charm.on.update_status.emit()
         self.assertTrue(isinstance(self.harness.charm.unit.status, WaitingStatus))
+
+    @patch_network_get(private_address="1.1.1.1")
+    def test_mongos_host(self):
+        """TBD."""
+        self.harness.charm.app_peer_data["external-connectivity"] = json.dumps(False)
+        mongos_host = self.harness.charm.get_mongos_host()
+        self.assertEqual(mongos_host, MONGOS_SOCKET_URI_FMT)
+
+        self.harness.charm.app_peer_data["external-connectivity"] = json.dumps(True)
+        mongos_host = self.harness.charm.get_mongos_host()
+        self.assertEqual(mongos_host, "1.1.1.1")

tests/unit/test_config_server_lib.py

@@ -31,7 +31,9 @@ def setUp(self):
             # related to duplicated events.
             delattr(DatabaseRequiresEvents, f"{CLUSTER_ALIAS}_database_created")
             delattr(DatabaseRequiresEvents, f"{CLUSTER_ALIAS}_endpoints_changed")
-            delattr(DatabaseRequiresEvents, f"{CLUSTER_ALIAS}_read_only_endpoints_changed")
+            delattr(
+                DatabaseRequiresEvents, f"{CLUSTER_ALIAS}_read_only_endpoints_changed"
+            )
         except AttributeError:
             # Ignore the events not existing before the first test.
             pass