schemathesis 0.3.0

Hypothesis strategies for Open API

Schemathesis

Schemathesis is a tool that generates test cases for your Open API / Swagger schemas.

The main goal is to bring property-based testing to web applications and verify if all values allowed by the schema are processed correctly by the application.

Empowered by Hypothesis, hypothesis_jsonschema and pytest.

NOTE: The library is WIP, the API is a subject to change.

Usage

To generate test cases for your schema you need:

• Create a parametrizer;
• Wrap a test with Parametrizer.parametrize method
• Provide a client and url of a running application instance

import pytest
import requests
from schemathesis import Parametrizer


schema = Parametrizer.from_path("path/to/schema.yaml")

@pytest.fixture(scope="session")
def client():
    with requests.Session() as session:
        yield session

@schema.parametrize()
def test_users_endpoint(client, case):
    url = "http://0.0.0.0:8080" + case.formatted_path
    response = client.request(
        case.method,
        url,
        params=case.query,
        json=case.body
    )
    assert response.status_code == 200

Each wrapped test will have the case fixture, that represents a hypothesis test case.

Case consists of:

• method
• formatted_path
• headers
• query
• body

For each schemathesis will create hypothesis strategies which will generate bunch of random inputs acceptable by schema. This data could be used to verify that your application works in the way as described in the schema or that schema describes expected behaviour.

For example the data could be send against running app container via requests and response is checked for an expected status code or error message.

To limit the number of examples you could use hypothesis.settings decorator on your test functions:

from hypothesis import settings

@settings(max_examples=5)
def test_something(client, case):
    ...

Documentation

For full documentation, please see [https://schemathesis.readthedocs.io/en/latest/]

Or you can look at the [docs/] directory in the repository.

Python support

Schemathesis supports Python 3.6, 3.7 and 3.8.

License

The code in this project is licensed under MIT license. By contributing to schemathesis, you agree that your contributions will be licensed under its MIT license.