feat: add deterministic small cluster seed

tests/integration/test_migrations.py

@@ -7,6 +7,7 @@ import asyncpg  # type: ignore[import-untyped]
 import pytest
 
 from app.db.migrations import migrate
+from app.simulation.seed import apply_seed, small_profile
 
 pytestmark = [
     pytest.mark.integration,
@@ -34,3 +35,23 @@ async def test_migration_is_repeatable_and_constraints_hold() -> None:
                 )
     finally:
         await connection.close()
+
+
+async def test_small_seed_is_idempotent() -> None:
+    connection = await asyncpg.connect(os.environ["TEST_DATABASE_URL"])
+    try:
+        await migrate(connection)
+        await apply_seed(connection, small_profile())
+        await apply_seed(connection, small_profile())
+        assert (
+            await connection.fetchval("SELECT count(*) FROM nodes WHERE name IN ('pve1', 'pve2')")
+            == 2
+        )
+        assert (
+            await connection.fetchval(
+                "SELECT count(*) FROM resources WHERE external_id IN ('100', 'local')"
+            )
+            == 2
+        )
+    finally:
+        await connection.close()

tests/unit/test_seed.py

@@ -0,0 +1,36 @@
+"""Deterministic seed profile tests."""
+
+from app.simulation.seed import small_profile, stable_id
+
+
+def test_small_profile_has_stable_logical_state() -> None:
+    first = small_profile()
+    second = small_profile()
+
+    assert first == second
+    assert first.logical_state() == {
+        "profile": "small",
+        "nodes": [
+            {"name": "pve1", "status": "online"},
+            {"name": "pve2", "status": "online"},
+        ],
+        "resources": [
+            {
+                "kind": "qemu",
+                "external_id": "100",
+                "node": "pve1",
+                "state": {"name": "demo", "status": "stopped"},
+            },
+            {
+                "kind": "storage",
+                "external_id": "local",
+                "node": "pve1",
+                "state": {"content": ["iso", "backup"]},
+            },
+        ],
+    }
+
+
+def test_stable_ids_are_namespaced_and_repeatable() -> None:
+    assert stable_id("qemu:100") == stable_id("qemu:100")
+    assert stable_id("qemu:100") != stable_id("qemu:101")