SNOW-629074 unstable sqlalchemy tests due to missing table/sequence (#318)

Author: sfc-gh-aling

DESCRIPTION.md

@@ -9,7 +9,7 @@ Source code is also available at:
 
 # Release Notes
 
-- v1.4.0(July 19, 2022)
+- v1.4.0(July 20, 2022)
 
   - Added support for `regexp_match`, `regexp_replace` in `sqlalchemy.sql.expression.ColumnOperators`.
   - Added support for Identity Column.

tests/sqlalchemy_test_suite/conftest.py

@@ -2,6 +2,8 @@
 # Copyright (c) 2012-2022 Snowflake Computing Inc. All rights reserved.
 #
 
+import sqlalchemy.testing.config
+from sqlalchemy import util
 from sqlalchemy.dialects import registry
 from sqlalchemy.testing.plugin.pytestplugin import *  # noqa
 from sqlalchemy.testing.plugin.pytestplugin import (
@@ -15,10 +17,31 @@
 from snowflake.sqlalchemy import URL
 
 from ..conftest import get_db_parameters
+from ..util import random_string
 
 registry.register("snowflake", "snowflake.sqlalchemy", "dialect")
 registry.register("snowflake.snowflake", "snowflake.sqlalchemy", "dialect")
-sqlalchemy_test_schema = "TEST_SCHEMA"
+TEST_SCHEMA = f"test_schema_{random_string(5)}"
+TEST_SCHEMA_2 = f"{TEST_SCHEMA}_2"
+
+
+# patch sqlalchemy.testing.config.Confi.__init__ for schema name randomization
+# same schema name would result in conflict as we're running tests in parallel in the CI
+def config_patched__init__(self, db, db_opts, options, file_config):
+    self._set_name(db)
+    self.db = db
+    self.db_opts = db_opts
+    self.options = options
+    self.file_config = file_config
+    self.test_schema = TEST_SCHEMA
+    self.test_schema_2 = TEST_SCHEMA_2
+
+    self.is_async = db.dialect.is_async and not util.asbool(
+        db.url.query.get("async_fallback", False)
+    )
+
+
+sqlalchemy.testing.config.Config.__init__ = config_patched__init__
 
 
 def pytest_sessionstart(session):
@@ -27,13 +50,13 @@ def pytest_sessionstart(session):
     # 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(f"CREATE SCHEMA IF NOT EXISTS {db_parameters['schema']}")
-        con.cursor().execute(f"CREATE SCHEMA IF NOT EXISTS {sqlalchemy_test_schema};")
+        con.cursor().execute(f"CREATE SCHEMA IF NOT EXISTS {TEST_SCHEMA};")
     _pytest_sessionstart(session)
 
 
 def pytest_sessionfinish(session):
     db_parameters = get_db_parameters()
     with snowflake.connector.connect(**db_parameters) as con:
         con.cursor().execute(f"DROP SCHEMA IF EXISTS {db_parameters['schema']}")
-        con.cursor().execute(f"DROP SCHEMA IF EXISTS f{sqlalchemy_test_schema}")
+        con.cursor().execute(f"DROP SCHEMA IF EXISTS f{TEST_SCHEMA}")
     _pytest_sessionfinish(session)

tests/util.py

@@ -0,0 +1,27 @@
+#
+# Copyright (c) 2012-2022 Snowflake Computing Inc. All rights reserved.
+#
+
+from __future__ import annotations
+
+import random
+import string
+from typing import Sequence
+
+
+def random_string(
+    length: int,
+    prefix: str = "",
+    suffix: str = "",
+    choices: Sequence[str] = string.ascii_lowercase,
+) -> str:
+    """Our convenience function to generate random string for object names.
+
+    Args:
+        length: How many random characters to choose from choices.
+        prefix: Prefix to add to random string generated.
+        suffix: Suffix to add to random string generated.
+        choices: A generator of things to choose from.
+    """
+    random_part = "".join([random.choice(choices) for _ in range(length)])
+    return "".join([prefix, random_part, suffix])