SNOW-610866 Add support for SQLAlchemy’s dialect tests (#305)

Author: sfc-gh-aling

setup.cfg

@@ -74,3 +74,7 @@ development =
     numpy
 pandas =
     snowflake-connector-python[pandas]<3.0.0
+
+[sqla_testing]
+requirement_cls=snowflake.sqlalchemy.requirements:Requirements
+profile_file=tests/profiles.txt

src/snowflake/sqlalchemy/requirements.py

@@ -0,0 +1,30 @@
+#
+# Copyright (c) 2012-2022 Snowflake Computing Inc. All rights reserved.
+#
+
+from sqlalchemy.testing import exclusions
+from sqlalchemy.testing.requirements import SuiteRequirements
+
+# TODO: check through the requirement list to determine which should be turned on/off
+
+
+class Requirements(SuiteRequirements):
+    @property
+    def autocommit(self):
+        return exclusions.open()
+
+    @property
+    def ctes(self):
+        return exclusions.open()
+
+    @property
+    def ctes_on_dml(self):
+        return exclusions.open()
+
+    @property
+    def ctes_with_update_delete(self):
+        return exclusions.open()
+
+    @property
+    def delete_from(self):
+        return exclusions.open()

tests/__init__.py

@@ -0,0 +1,3 @@
+#
+# Copyright (c) 2012-2022 Snowflake Computing Inc. All rights reserved.
+#

tests/conftest.py

@@ -12,10 +12,11 @@
 from sqlalchemy import create_engine
 
 import snowflake.connector
-from parameters import CONNECTION_PARAMETERS
 from snowflake.connector.compat import IS_WINDOWS
 from snowflake.sqlalchemy import URL, dialect
 
+from .parameters import CONNECTION_PARAMETERS
+
 CLOUD_PROVIDERS = {"aws", "azure", "gcp"}
 EXTERNAL_SKIP_TAGS = {"internal"}
 INTERNAL_SKIP_TAGS = {"external"}

tests/sqlalchemy_test_suite/README.md

@@ -0,0 +1,21 @@
+# SQLAlchemy Compliance Tests
+
+SQLAlchemy offers tests to test SQLAlchemy dialects work properly. This directory applies these tests
+to the Snowflake SQLAlchemy dialect.
+
+**Please be aware that the test suites are not collected in pytest by default** -- the directory is ignored in `tox.ini`.
+There are majorly three issues with the sqlalchemy test suites:
+1. Importing sqlalchemy pytest plugin will result in Snowflake SQLAlchemy dialect specific tests not
+being collected.
+2. Putting test_suites.py and related conftest config under root tests dir would make pytest fail to collect cfg
+information such as requirements, and customized session db config does not work as expected (schema not set).
+
+Running sqlalchemy test suites from a separate directory does not have the aforementioned issues. Thus, we skip the
+path in the config, and run test suites separately.
+
+To run the SQLAlchemy test suites, please specify the directory of the test suites when running pytest command:
+
+```bash
+$cd snowflake-sqlalchemy
+$pytest tests/sqlalchemy_test_suite
+```

tests/sqlalchemy_test_suite/__init__.py

@@ -0,0 +1,3 @@
+#
+# Copyright (c) 2012-2022 Snowflake Computing Inc. All rights reserved.
+#

tests/sqlalchemy_test_suite/conftest.py

@@ -0,0 +1,26 @@
+#
+# Copyright (c) 2012-2022 Snowflake Computing Inc. All rights reserved.
+#
+
+from sqlalchemy.dialects import registry
+from sqlalchemy.testing.plugin.pytestplugin import *  # noqa
+from sqlalchemy.testing.plugin.pytestplugin import (
+    pytest_sessionstart as _pytest_sessionstart,
+)
+
+import snowflake.connector
+from snowflake.sqlalchemy import URL
+
+from ..conftest import get_db_parameters
+
+registry.register("snowflake", "snowflake.sqlalchemy", "dialect")
+registry.register("snowflake.snowflake", "snowflake.sqlalchemy", "dialect")
+
+
+def pytest_sessionstart(session):
+    db_parameters = get_db_parameters()
+    session.config.option.dburi = [URL(**db_parameters)]
+    # schema name with 'TEST_SCHEMA' is required by some tests of the sqlalchemy test suite
+    with snowflake.connector.connect(**db_parameters) as con:
+        con.cursor().execute("CREATE SCHEMA IF NOT EXISTS TEST_SCHEMA")
+    _pytest_sessionstart(session)