test(automations/templating): lock render, filters, environment, context

render.py (4): variable substitution, StrictUndefined raises on missing
keys, evaluate_predicate coerces to bool, render_value walks dicts/lists
and renders string leaves.

filters.py (4): slugify produces URL-safe output, date formats datetime
with strftime, date(None) → "" so templates can write
{{ inputs.last_fired_at | date }} on first run, date(str) passes through.

environment.py (4): the sandbox boundary — disallowed Jinja built-ins
(e.g. pprint) raise, and the finalize hook coerces non-string outputs
to predictable wire shapes (datetime → ISO, None → "", dict → JSON).

context.py (1): build_run_context exposes {run, inputs, steps} with the
exact shape every plan template body relies on.

13 tests total, all pure unit.

surfsense_backend/tests/unit/automations/templating/test_context.py

@@ -0,0 +1,53 @@
+"""Lock the ``{run, inputs, steps}`` namespace exposed to every template."""
+
+from __future__ import annotations
+
+from datetime import UTC, datetime
+from uuid import UUID
+
+import pytest
+
+from app.automations.templating.context import build_run_context
+
+pytestmark = pytest.mark.unit
+
+
+def test_build_run_context_exposes_run_inputs_and_steps_namespaces() -> None:
+    """The namespace handed to templates groups run metadata under ``run``,
+    runtime + static inputs under ``inputs``, and step outputs (keyed by
+    ``output_as`` / ``step_id``) under ``steps``. Locks the contract that
+    every plan template body relies on."""
+    creator = UUID("00000000-0000-0000-0000-000000000001")
+    started = datetime(2026, 5, 28, 14, 30, tzinfo=UTC)
+
+    ctx = build_run_context(
+        run_id=42,
+        automation_id=7,
+        automation_name="Weekly digest",
+        automation_version=3,
+        search_space_id=1,
+        creator_id=creator,
+        trigger_id=11,
+        trigger_type="schedule",
+        started_at=started,
+        attempt=2,
+        inputs={"topic": "weekly"},
+        step_outputs={"summarize": {"text": "ok"}},
+    )
+
+    assert ctx == {
+        "run": {
+            "id": 42,
+            "automation_id": 7,
+            "automation_name": "Weekly digest",
+            "automation_version": 3,
+            "search_space_id": 1,
+            "creator_id": creator,
+            "trigger_id": 11,
+            "trigger_type": "schedule",
+            "started_at": started,
+            "attempt": 2,
+        },
+        "inputs": {"topic": "weekly"},
+        "steps": {"summarize": {"text": "ok"}},
+    }