I’m having some issues with using Pytest. My Flask API uses pyodbc to talk to a MSSQL server db. The API runs in a Docker container and I’m running this on my Mac.

I have a unit test for a healthcheck (root level ie localhost:5000/) route that is as follows:

from app import app

def test_healthcheck(self):
    """
    Test the healthcheck endpoint
    EXPECTS: A 200 status code and the string "Healthcheck"
    """
    with app.test_client() as test_client:
        response = self.app.get("/")
        assert response.status_code == 200
        assert response.data, b"Healthcheck"

And my project is structured as follows:

myproject
| app.py
| — api/
       | — routes/
       | — utils/
                | db.py
                | helpers.py

| — tests/
         | test_healthcheck.py

When I run python3 -m pytest, I get the following error:

ERROR tests/test_healthcheck.py - pyodbc.Error: ('01000', "[01000] [unixODBC][Driver Manager]Can't open lib 'ODBC Driver 18 for SQL Server' : file not found (0) (SQLDriverConnect)")

The error logs show the pyodbc error stems from the pyodbc.connect() line my db.py util file, which is a class-based abstraction of the db operations.

class DB:
    """
    Class to abstract out MS SQL Server DB operations
    """

    def __init__(self):
        self.conn_str = os.getenv("CONN_STR")
        if not self.conn_str:
            raise RuntimeError("Missing 'CONN_STR' env var")
        self.conn = pyodbc.connect(self.conn_str)

But I have pyodbc installed on my local machine, and when I run the API in Docker, I don’t encounter any pyodbc issues.

In case this helps, app.py is as follows:

import logging
from flask import Flask
from dotenv import load_dotenv

from api.routes.healthcheck import bp as health_bp
from api.routes.generate import bp as generate_bp

load_dotenv()

app = Flask(__name__)
app.register_blueprint(health_bp)
app.register_blueprint(generate_bp)

logging.basicConfig(level=logging.INFO)
logging.getLogger("werkzeug").setLevel(logging.INFO)

I see the Pytest docs talking about a conftest.py file, but this seems to rely on the factory app pattern, which this app does not. Do I need conftest? And how do I get this pyodbc error to go away?