added test for provider

lib/charms/grafana_k8s/v0/grafana_source.py

@@ -429,13 +429,13 @@ def update_source(self, source_url: Optional[str] = ""):
                 continue
             self._set_sources(rel)
 
-    def get_source_uids(self) -> Dict[Relation, str]:
+    def get_source_uids(self) -> Dict[Relation, Dict[str, str]]:
         """Get the datasource UID(s) assigned by the remote end(s) to this datasource."""
         uids = {}
         for rel in self._charm.model.relations.get(self._relation_name, []):
             if not rel:
                 continue
-            uids[rel] = rel.data[rel.app]["datasource_uid"]
+            uids[rel] = json.loads(rel.data[rel.app]["datasource_uids"])
         return uids
 
     def _set_sources_from_event(self, event: RelationJoinedEvent) -> None:

tests/scenario/test_datasources.py

@@ -1,7 +1,10 @@
 import json
 
+from ops import CharmBase, Framework
 from ops.testing import Container, State
-from scenario import Relation, PeerRelation
+from scenario import Relation, PeerRelation, Context
+
+from charms.grafana_k8s.v0.grafana_source import GrafanaSourceProvider
 
 containers = [
     Container(name="grafana", can_connect=True),
@@ -39,3 +42,44 @@ def test_datasource_sharing(ctx):
         "remote_host/0": "juju_foo_bar_baz_0",
         "remote_host/1": "juju_foo_bar_baz_1",
     }
+
+def test_datasource_get():
+    # GIVEN a datasource relation with two remote units
+    local_ds_uids = {
+        "prometheus/0": "some-datasource-uid",
+        "prometheus/1": "some-datasource-uid",
+    }
+    datasource = Relation(
+        "grafana-source",
+        remote_app_name="remote_host",
+        local_unit_data={"grafana_source_host": "somehost:80"},
+        local_app_data={
+            "grafana_source_data": json.dumps(
+                {"model": "foo", "model_uuid": "bar", "application": "baz", "type": "tempo"}
+            )
+        },
+        remote_app_data={
+            "datasource_uids": json.dumps(local_ds_uids)
+        }
+    )
+    state = State(
+        leader=True, relations={datasource}
+    )
+
+    # WHEN relation-changed fires for a datasource relation
+    class MyProviderCharm(CharmBase):
+        META={"name":"edgar",
+              "provides":{"grafana-source": {"interface": "grafana_datasource"}}}
+
+        def __init__(self, framework: Framework):
+            super().__init__(framework)
+            self.source_provider = GrafanaSourceProvider(self, "tempo",
+                                                         source_url="somehost",
+                                                         source_port="80")
+
+    ctx = Context(MyProviderCharm, MyProviderCharm.META)
+    with ctx(ctx.on.relation_changed(datasource), state) as mgr:
+        charm = mgr.charm
+        # THEN we can see our datasource uids via the provider
+        assert list(charm.source_provider.get_source_uids().values())[0] == local_ds_uids
+