From 7d3bab67eaddb7bfb75c4cab6da851aff7745209 Mon Sep 17 00:00:00 2001
From: Pietro Pasotti <starfire.daemon@gmail.com>
Date: Thu, 5 Oct 2023 17:01:18 +0200
Subject: [PATCH 1/2] test

---
 scenario/runtime.py              |  7 ++++++-
 scenario/state.py                |  5 +----
 tests/test_e2e/test_relations.py | 36 ++++++++++++++++++++++++++++++++
 3 files changed, 43 insertions(+), 5 deletions(-)

diff --git a/scenario/runtime.py b/scenario/runtime.py
index 863d0f1d..0de7b991 100644
--- a/scenario/runtime.py
+++ b/scenario/runtime.py
@@ -231,13 +231,18 @@ def _get_event_env(self, state: "State", event: "Event", charm_root: Path):
                         "but you probably should be parametrizing the event with `remote_unit_id` "
                         "to be explicit.",
                     )
-                else:
+                elif len(remote_unit_ids) > 1:
                     remote_unit_id = remote_unit_ids[0]
                     logger.warning(
                         "remote unit ID unset, and multiple remote unit IDs are present; "
                         "We will pick the first one and hope for the best. You should be passing "
                         "`remote_unit_id` to the Event constructor.",
                     )
+                else:
+                    logger.warning(
+                        "remote unit ID unset; no remote unit data present. "
+                        "Is this a realistic scenario?",  # TODO: is it?
+                    )
 
             if remote_unit_id is not None:
                 remote_unit = f"{remote_app_name}/{remote_unit_id}"
diff --git a/scenario/state.py b/scenario/state.py
index 9b612e20..69d7cb8f 100644
--- a/scenario/state.py
+++ b/scenario/state.py
@@ -193,7 +193,7 @@ def _update_metadata(
 
 
 def normalize_name(s: str):
-    """Event names need underscores instead of dashes."""
+    """Event names, in Scenario, uniformly use underscores instead of dashes."""
     return s.replace("-", "_")
 
 
@@ -927,9 +927,6 @@ def __call__(self, remote_unit_id: Optional[int] = None) -> "Event":
         return self.replace(relation_remote_unit_id=remote_unit_id)
 
     def __post_init__(self):
-        if "-" in self.path:
-            logger.warning(f"Only use underscores in event paths. {self.path!r}")
-
         path = normalize_name(self.path)
         # bypass frozen dataclass
         object.__setattr__(self, "path", path)
diff --git a/tests/test_e2e/test_relations.py b/tests/test_e2e/test_relations.py
index 00f4926f..e5be3400 100644
--- a/tests/test_e2e/test_relations.py
+++ b/tests/test_e2e/test_relations.py
@@ -223,6 +223,42 @@ def callback(charm: CharmBase, event):
     )
 
 
+@pytest.mark.parametrize(
+    "evt_name",
+    ("changed", "broken", "departed", "joined", "created"),
+)
+def test_relation_events_no_remote_units(mycharm, evt_name, caplog):
+    relation = Relation(
+        endpoint="foo",
+        interface="foo",
+        remote_units_data={},  # no units
+    )
+
+    def callback(charm: CharmBase, event):
+        assert event.app  # that's always present
+        assert not event.unit
+
+    mycharm._call = callback
+
+    trigger(
+        State(
+            relations=[
+                relation,
+            ],
+        ),
+        getattr(relation, f"{evt_name}_event"),
+        mycharm,
+        meta={
+            "name": "local",
+            "requires": {
+                "foo": {"interface": "foo"},
+            },
+        },
+    )
+
+    assert "remote unit ID unset; no remote unit data present" in caplog.text
+
+
 @pytest.mark.parametrize("data", (set(), {}, [], (), 1, 1.0, None, b""))
 def test_relation_unit_data_bad_types(mycharm, data):
     with pytest.raises(StateValidationError):

From 518cb9e3505ee195810b45102d0a9e7c3fbb3325 Mon Sep 17 00:00:00 2001
From: Pietro Pasotti <starfire.daemon@gmail.com>
Date: Thu, 5 Oct 2023 17:03:19 +0200
Subject: [PATCH 2/2] vbump

---
 pyproject.toml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pyproject.toml b/pyproject.toml
index 6b647aeb..9ac8cf8b 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -8,7 +8,7 @@ build-backend = "setuptools.build_meta"
 [project]
 name = "ops-scenario"
 
-version = "5.3"
+version = "5.3.1"
 
 authors = [
     { name = "Pietro Pasotti", email = "pietro.pasotti@canonical.com" }