Additional features

Schemathesis ships a set of optional features that could help to tune your tests.

Unique data generation

By default, Schemathesis may generate the same test cases as all data is randomized. If this behavior does not match your expectations, or your test budgets, you can force Schemathesis to generate unique test cases.

In CLI:

$ st run --contrib-unique-data https://example.schemathesis.io/openapi.json

Important

The schemathesis.contrib.unique_data hook is DEPRECATED. The concept of this feature does not fit the core principles of Hypothesis where strategies are configurable on a per-example basis but this feature implies uniqueness across examples. This leads to cryptic error messages about external state and flaky test runs, therefore it will be removed in Schemathesis 4.0

In Python tests:

from schemathesis import contrib

# This is a global hook that will affect all the tests
contrib.unique_data.install()

Uniqueness is determined by the following parts of the generated data:

  • media_type

  • path_parameters

  • headers

  • cookies

  • query

  • body

Fill missing examples

The --contrib-openapi-fill-missing-examples option complements --hypothesis-phases=explicit by generating a random example for operations that lack explicit examples in the schema.

In CLI:

$ st run --contrib-openapi-fill-missing-examples --hypothesis-phases=explicit \
      https://example.schemathesis.io/openapi.json

In Python tests:

from schemathesis.contrib.openapi import fill_missing_examples

fill_missing_examples.install()

This feature ensures that all operations, even those without specified examples, are tested when running with --hypothesis-phases=explicit.

Note

This option is designed for users transitioning from Dredd to Schemathesis.

UUID data for format: uuid in Open API

Open API 2.0 / 3.0 do not declare the uuid format as built-in, hence it is available as an extension:

from schemathesis.contrib.openapi import formats

formats.uuid.install()

You could also enable it via the --contrib-openapi-formats-uuid CLI option.

Note

If you enable the OpenAPI 3.1 experimental feature, the UUID format support is automatically enabled. Refer to the Experimental Features section for more details.