fix(test): clean_db fixtures does not break if table is missing

ckan/model/__init__.py

@@ -270,10 +270,22 @@ def delete_all(self) -> None:
         self.session.remove()
         ## use raw connection for performance
         connection: Any = self.session.connection()
+        inspector = sa.inspect(connection)
         tables = reversed(self.metadata.sorted_tables)
         for table in tables:
+            # `alembic_version` contains current migration version of the
+            # DB. If we drop this information, next attempt to apply migrations
+            # will fail. Don't worry about `<PLUGIN>_alembic_version` tables
+            # created by extensions - CKAN metadata does not track them, so
+            # they'll never appear in this list.
             if table.name == 'alembic_version':
                 continue
+
+            # if custom model imported without migrations applied,
+            # corresponding table can be missing from DB
+            if not inspector.has_table(table):
+                continue
+
             connection.execute(sa.delete(table))
         self.session.commit()
         log.info('Database table data deleted')

ckan/tests/pytest_ckan/test_fixtures.py

@@ -4,12 +4,13 @@
 
 import pytest
 from urllib.parse import urlparse
-from sqlalchemy import inspect
+from sqlalchemy import inspect, Column, Integer
 
 import ckan.plugins as plugins
 from ckan.common import config, asbool
 from ckan.tests import factories
 from ckan.lib.redis import connect_to_redis
+from ckan.model.base import BaseModel
 
 
 def test_ckan_config_fixture(ckan_config):
@@ -180,3 +181,22 @@ def test_reset_redis(self, redis, reset_redis):
 
         reset_redis()
         assert not redis.get("BBB-3")
+
+
+class CustomTestModel(BaseModel):
+    __tablename__ = "test_table"
+    id = Column(Integer, primary_key=True)
+
+
+@pytest.mark.parametrize("_n", [1, 2])
+@pytest.mark.usefixtures("clean_db")
+def test_clean_db_does_not_break_with_custom_models(_n):
+    """This test verifies that `CustomTestModel` that has no corresponding
+    table in DB is ignored by `clean_db` fixture. If this test is executed
+    individually, on first run DB may be empty and `clean_db` doesn't try to
+    delete anything. So we have to run this test two times to guarantee, that
+    on the second execution tables are created and `clean_db` invokes `DELETE
+    ...` statement.
+
+    """
+    pass