chore(release): add alembic preflight check

tests/unit/test_alembic_preflight.py

@@ -0,0 +1,45 @@
+from scripts.alembic_preflight import AlembicPreflightResult
+
+
+def test_alembic_preflight_action_for_current_version():
+    result = AlembicPreflightResult(
+        has_alembic_version=True,
+        business_table_count=12,
+        current_revision="002",
+        head_revision="002",
+    )
+
+    assert result.action == "upgrade_head_noop_or_verify"
+
+
+def test_alembic_preflight_action_for_old_version():
+    result = AlembicPreflightResult(
+        has_alembic_version=True,
+        business_table_count=12,
+        current_revision="001",
+        head_revision="002",
+    )
+
+    assert result.action == "upgrade_head"
+
+
+def test_alembic_preflight_action_for_existing_tables_without_version():
+    result = AlembicPreflightResult(
+        has_alembic_version=False,
+        business_table_count=12,
+        current_revision=None,
+        head_revision="002",
+    )
+
+    assert result.action == "stamp_head_then_upgrade_head"
+
+
+def test_alembic_preflight_action_for_empty_database():
+    result = AlembicPreflightResult(
+        has_alembic_version=False,
+        business_table_count=0,
+        current_revision=None,
+        head_revision="002",
+    )
+
+    assert result.action == "upgrade_head_empty_database"