# HypothesisWorks/hypothesis

The property-based testing library for Python

Repository: https://github.com/HypothesisWorks/hypothesis
Canonical: https://ross.abutalabs.com/products/hypothesis
Homepage: https://hypothesis.works
Language: Python
License: NOASSERTION
License Family: other
Topics: python, testing, fuzzing, property-based-testing
Last push: 2026-08-25T07:13:15+00:00

## Health v2 (maintenance only)
Score: 95/100 (v2, computed 2026-09-03T02:39:23.370411+00:00)
- activity 99, release rhythm 86, longevity 100
- inputs: {"age_days": 4924, "days_push": 8, "days_rel": 17, "gap_med": 0, "n_releases_24m": 330}
- flags: no_license
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 8913, forks 672 (observed 2026-08-28T04:10:26.261668+00:00)

## What it is
Hypothesis is the property-based testing library for Python, generating randomized test inputs from user-described strategies and shrinking failures to minimal examples. It integrates with pytest, unittest, and other runners and is the most widely used property-based testing tool.

## Use cases
- generate random test inputs for python functions
- find edge cases in my code automatically
- shrink failing test cases to minimal examples
- property-based testing with pytest
- test sorting or parsing functions against all inputs
- fuzz test python libraries

## When to choose
- you write Python tests and want broader input coverage than hand-written examples
- you want automatic edge-case discovery and minimal failing examples
- you use pytest or unittest and want a drop-in testing extension

## When to avoid
- you need property-based testing in a non-Python language
- you only need deterministic example-based unit tests
- you need coverage-guided binary fuzzing of compiled code

## Facets
- artifact type: library
- maturity: stable
- function: testing, fuzzing, benchmarking
- domain: testing, developer-tools
- platform: python, cross-platform, cli
- tags: property-based-testing, pytest, test-generation, shrinking, randomized-testing, python

## Member repositories
- HypothesisWorks/hypothesis (main) score 95

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:10:26.261668+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-29T17:24:42.551029+00:00, confidence not recorded.
  - readme: https://github.com/HypothesisWorks/hypothesis (fetched 2026-08-28T04:10:26.261668+00:00, sha bdea363861e9)
  - homepage: https://hypothesis.works (fetched 2026-08-29T08:24:50.132572+00:00, sha 6a8d595ede7c)
- Data as of 2026-08-30T08:39:29.467469+00:00.