fakesnow 0.7.1

Fake Snowflake Connector for Python. Run Snowflake DB locally.

fakesnow ❄️

Fake Snowflake Connector for Python. Run and mock Snowflake DB locally.

Install

pip install fakesnow

Usage

import fakesnow
import snowflake.connector

with fakesnow.patch():
    conn = snowflake.connector.connect()

    print(conn.cursor().execute("SELECT 'Hello fake world!'").fetchone())

The following imports are automatically patched:

• import snowflake.connector.connect
• import snowflake.connector.pandas_tools.write_pandas

To patch modules that use the from ... import syntax, manually specify them, eg: if mymodule.py has the import:

from snowflake.connector.pandas_tools import write_pandas

Then patch it using:

with fakesnow.patch("mymodule.write_pandas"):
    ...

pytest fixtures are provided for testing. Example conftest.py:

from typing import Iterator

import fakesnow.fixtures
import pytest

pytest_plugins = fakesnow.fixtures.__name__

@pytest.fixture(scope="session", autouse=True)
def setup(_fakesnow_session: None) -> Iterator[None]:
    # the standard imports are now patched
    ...
    yield

Or with from ... import patch targets:

from typing import Iterator

import fakesnow
import pytest

@pytest.fixture(scope="session", autouse=True)
def _fakesnow_session() -> Iterator[None]:
    with fakesnow.patch("mymodule.write_pandas"):
        yield

Implementation coverage

• cursors and standard SQL
• get_result_batches()
• information schema
• multiple databases
• parameter binding
• table comments
• write_pandas(..)
• access control
• standalone/out of process api/support for faking non-python connectors
• stored procedures

Partial support

• date functions
• regex functions
• semi-structured data
• tags

For more detail see tests/test_fakes.py

Caveats

• VARCHAR field sizes are not enforced unlike Snowflake which will error with "User character length limit (xxx) exceeded by string" when you try to insert a string longer than the column limit.

Contributing

See CONTRIBUTING.md to get started and develop in this repo.