fakesnow

0.11.6 verified Mon Apr 27 auth: no python

Fake Snowflake Connector for Python. Run, mock and test Snowflake DB locally using DuckDB. Current version: 0.11.6. Release cadence: approximately monthly.

pip install fakesnow

Common errors

error ModuleNotFoundError: No module named 'snowflake' ↓

cause Missing snowflake-connector-python dependency

fix

pip install snowflake-connector-python

error fakesnow.patch() not found ↓

cause Incorrect import; fakesnow does not export patch if imported incorrectly

fix

Use 'from fakesnow import patch' or 'import fakesnow; fakesnow.patch()'

error snowflake.connector.errors.DatabaseError: 000404 (42S02): Table ... does not exist ↓

cause Unsupported SQL feature in fakesnow (e.g., certain DDL variations)

fix

Simplify the statement or check fakesnow's supported SQL subset (see GitHub README).

Warnings

breaking Python 3.9 support dropped in v0.11.0 ↓

fix Upgrade to Python >=3.10 or pin fakesnow <0.11.0

breaking Information schema column names now uppercase (v0.10.0) ↓

fix Update queries to use uppercase column names (e.g., 'TABLE_NAME' instead of 'table_name') or wrap in double quotes

gotcha fakesnow does NOT mock all Snowflake features. Unsupported SQL may raise errors or produce incorrect results. ↓

fix Check GitHub issues/README for known limitations before relying on fakesnow for complex queries.

gotcha Always call fakesnow.patch() BEFORE importing snowflake.connector if possible, or at least before any connection attempt. ↓

fix Run 'fakesnow.patch()' at the top of your test file or conftest.py, before any snowflake imports.

Install

pip install fakesnow[server]

Imports

fakesnow
wrong
```
from fakesnow import connect
```
correct
```
import fakesnow
```
fakesnow does not expose a connect function; you use snowflake.connector.connect after fakesnow.patch()
fakesnow.patch
wrong
```
fakesnow.patch()
```
correct
```
from fakesnow import patch; patch()
```
If you do 'import fakesnow' then you must call fakesnow.patch(), but it is clearer to import patch directly
snowflake.connector.connect
wrong
```
import fakesnow; conn = fakesnow.connect(...)
```
correct
```
import snowflake.connector; conn = snowflake.connector.connect(...)
```
After fakesnow.patch(), snowflake.connector.connect is replaced with a fake version. Don't use fakesnow.connect.

Quickstart

Patch snowflake.connector, create a fake connection, run SQL locally.

import fakesnow
import snowflake.connector

fakesnow.patch()

conn = snowflake.connector.connect(
    user='test',
    password='test',
    account='test',
    database='MYDB',
    schema='PUBLIC',
    warehouse='test'
)

cur = conn.cursor()
cur.execute('CREATE TABLE users (id INT, name STRING)')
cur.execute("INSERT INTO users VALUES (1, 'Alice')")
cur.execute('SELECT * FROM users')
print(cur.fetchall())