Unit Testing Guide

Prerequisites

1. Create a virtual python environment under azure-functions-python-worker project directory (supports Python 3.6/3.7/3.8)
2. Run python -m pip install --index-url https://test.pypi.org/simple/ --extra-index-url https://pypi.org/simple -U -e .[dev] to install the dependencies
3. Run python setup.py webhost to download the WEBHOST defined in setup.py
4. Test a case with pytest ./tests/unittests/test_code_quality.py::TestCodeQuality::test_mypy

Python functions for Azure can be tested like regular Python code using standard testing frameworks. For most bindings it is possible to create a mock input object by creating an instance of an appropriate class from the azure.functions package.

For example, below is a mock test of an HttpTrigger function:

myapp/__init__.py:

import azure.functions as func

def my_function(req: func.HttpRequest) -> func.HttpResponse:
    name = req.params.get('name')
    if not name:
        name = 'Incognito'
    return func.HttpResponse(f"Hello {name}!")

myapp/test_func.py:

import unittest

import azure.functions as func
from . import my_function

class TestFunction(unittest.TestCase):
    def test_my_function(self):
        # Construct a mock HTTP request.
        req = func.HttpRequest(
            method='GET',
            body=None,
            url='/my_function', 
            params={'name': 'Test'})

        # Call the function.
        resp = my_function(req)

        # Check the output.
        self.assertEqual(
            resp.get_body(), 
            'Hello, Test!',
        )

Another example, with a queue trigger function:

queueapp/__init__.py:

import azure.functions as func

def my_function(msg: func.QueueMessage) -> str:
    return f'msg body: {msg.get_body().decode()}'

queueapp/test_func.py:

import unittest

import azure.functions as func
from . import my_function

class TestFunction(unittest.TestCase):
    def test_my_function(self):
        # Construct a mock Queue message.
        req = func.QueueMessage(
            body=b'test')

        # Call the function.
        resp = my_function(req)

        # Check the output.
        self.assertEqual(
            resp, 
            'msg body: test',
        )