istranin.dev code examples

Runnable code examples for Python testing, pytest, FastAPI, and AI engineering articles on istranin.dev.

Browse examples · Getting started · Articles · Courses

Each directory is a self-contained project with its own dependencies, pyproject.toml, and uv.lock. Read the corresponding article for the explanation, then use its example to run and explore the code.

Article examples

Example	Topics	Article
Pytest fixtures and mocking for AI agents	Scripted models, OpenAI and Anthropic adapters, HTTP mocks, offline CI	Read ↗
Your first pytest test	Given-When-Then, plain assertions, failure reports, boundaries	Read ↗
Python unit testing best practices	Behavior, parametrization, explicit fixtures, autospecced collaborators	Read ↗
GitHub Actions Python testing	Python matrix, coverage, JUnit reports, stable merge check	Read ↗
FastAPI testing with pytest	API testing, TestClient, validation, boundary cases	Read ↗
Behavior-driven development in Python with pytest-bdd	Shared examples, Gherkin, scenario outlines, reservation outcomes, TDD integration	Read ↗
LangGraph agent testing with pytest	Agent graphs, tool calls, pytest-mock, failure paths	Read ↗
Pytest hooks examples	CLI options, markers, collection, hook wrappers, terminal reports	Read ↗
Pytest mocking tutorial	mocker, class and method patches, mock drift, lookup targets, decorators	Read ↗
Pytest fixtures and parametrization	Fixture architecture, factories, indirect setup, dynamic cases, scope costs, parallel workers	Read ↗
Test-driven development in Python with pytest	Red-green-refactor, exceptions, parametrization, state boundaries	Read ↗
Unit testing vs integration testing vs E2E in Python	Test boundaries, real configuration, subprocess CLI tests, regression and acceptance	Read ↗

Open an example directory and follow its README to install the locked dependencies and run the code.

Getting started

You need Python 3.13 or newer and uv. Clone the repository and choose an example. For instance, to run the FastAPI tests:

git clone https://github.com/artem-istranin/istranin-dev-code-examples.git
cd istranin-dev-code-examples/fastapi-testing-pytest
uv sync --locked
uv run pytest test_main.py -v

Run commands inside the example directory. Each example keeps its own environment and locked dependencies; the repository root is a catalog. The example README includes its expected results and any additional commands or exercises.

Adding an example

Keep each example focused on its companion article and independently runnable. Follow the same README structure used throughout this repository:

1. The istranin.dev wordmark, example title, and a direct link to the companion article.
2. Overview — the example's purpose and scope.
3. Requirements — Python, uv, and any example-specific prerequisites.
4. Run the example — commands and expected results.
5. Project files — a map of the relevant source, tests, and dependency files.
6. Any article-specific walkthroughs, experiments, or sources, followed by the shared navigation footer.

Preserve each article's teaching content, include its pyproject.toml and uv.lock, and add the example and article links to the catalog above.

Author and license

Created by Artem Istranin. Find the full articles and practical courses on istranin.dev.

This repository is licensed under the Apache License 2.0.