pydantic-fixturegen: deterministic Pydantic fixtures, JSON generator, secure sandbox

Pydantic v2 deterministic fixtures, pytest fixtures, JSON generator, secure sandboxed CLI with Pluggy providers.

Generate deterministic Pydantic v2 data, pytest fixtures, and JSON quickly with a safe, task-focused CLI built for modern testing workflows.

Why

• You keep tests reproducible with cascaded seeds across random, Faker, and optional NumPy.
• You run untrusted models inside a safe-import sandbox with network, filesystem, and memory guards.
• You drive JSON, pytest fixtures, schemas, and explanations from the CLI or Python helpers.
• You extend generation with Pluggy providers and preset bundles without forking core code.

You also stay observant while you work: every command can emit structured logs, diff artifacts against disk, and surface sandbox warnings so you catch regressions before they land.

Install

pip install pydantic-fixturegen
# Extras: orjson, regex, hypothesis, watch
pip install 'pydantic-fixturegen[all]'

Other flows → docs/install.md

Quick start

1. Create a small Pydantic v2 model file.
2. List models: pfg list ./models.py
3. Generate JSON: pfg gen json ./models.py --include models.User --n 2 --indent 2 --out ./out/User
4. Generate fixtures: pfg gen fixtures ./models.py --out tests/fixtures/test_user.py --cases 3 Full steps → docs/quickstart.md

JSON, fixtures, and schema commands all share flags like --include, --exclude, --seed, --preset, and --watch, so once you learn one flow you can handle the rest without re-reading the help pages.

Basics

Core usage (top 5)

pfg list <path>
pfg gen json <target> [--n --jsonl --indent --out]
pfg gen fixtures <target> [--style --scope --cases --out]
pfg gen schema <target> --out <file>
pfg doctor <target>

• pfg list discovers models with AST or safe-import; add --ast when you must avoid imports.
• pfg gen json emits JSON or JSONL; scale with --n, --jsonl, --shard-size, and --freeze-seeds.
• pfg gen fixtures writes pytest modules; tune --style, --scope, --cases, and --return-type.
• pfg gen schema dumps JSON Schema atomically; point --out at a file or directory template.
• pfg doctor audits coverage and sandbox warnings; fail builds with --fail-on-gaps.

All commands → docs/cli.md

Basic configuration

key	type	default	purpose
seed	int | str | null	null	Global seed
locale	str	en_US	Faker locale
union_policy	enum	first	Union branch
enum_policy	enum	first	Enum choice
json.indent	int	2	Pretty JSON
json.orjson	bool	false	Fast JSON
emitters.pytest.style	enum	functions	Fixture style
emitters.pytest.scope	enum	function	Fixture scope

[tool.pydantic_fixturegen]
seed = 42
[tool.pydantic_fixturegen.json]
indent = 2

Full matrix and precedence → docs/configuration.md

Common tasks

• Freeze seeds for CI determinism → docs/seeds.md
• Use watch mode → docs/quickstart.md#watch-mode
• Templated output paths → docs/output-paths.md
• Provider customization → docs/providers.md
• Capture explain trees or JSON diagnostics for review → docs/explain.md

Documentation

Index · Quickstart · Cookbook · Configuration · CLI · Concepts · Features · Security · Architecture · Troubleshooting · Alternatives

Community

Open issues for bugs or ideas, start Discussions for design questions, and follow the security policy when you disclose sandbox bypasses.

License

MIT. See LICENSE.