hypothesis-jsonschema

A Hypothesis strategy for generating data that matches some JSON schema.

Here's the PyPI page.

API

The public API consists of just one function: hypothesis_jsonschema.from_schema, which takes a JSON schema and returns a strategy for allowed JSON objects.

JSONSchema drafts 04, 05, and 07 are fully tested and working. As of version 0.11, this includes resolving non-recursive references!

For details on how to use this strategy in your tests, see the Hypothesis docs.

Supported versions

hypothesis-jsonschema requires Python 3.6 or later. In general, 0.x versions will require very recent versions of all dependencies because I don't want to deal with compatibility workarounds.

hypothesis-jsonschema may make backwards-incompatible changes at any time before version 1.x - that's what semver means! - but I've kept the API surface small enough that this should be avoidable. The main source of breaks will be if or when schema that never really worked turn into explicit errors instead of generating values that don't quite match.

You can sponsor me to get priority support, roadmap input, and prioritized feature development.

Contributing to hypothesis-jsonschema

We love external contributions - and try to make them both easy and fun. You can read more details in our contributing guide, and see everyone who has contributed on GitHub. Thanks, everyone!

Changelog:

0.13.0 - 2020-05-20

• Improved canonicalisation of uniqueItems: false case
• Improved canonicalisation of numeric schemas
• Reuse jsonschema validators during canonicalisation (performance improvement)

0.12.1 - 2020-04-14

• Added a strategy for the "color" format
• Only apply string length filter when needed (small performance improvement)

0.12.0 - 2020-04-08

• Fixed error in resolution of certain $ref\ s
• Improved canonicalisation of anyOf and contains keys

0.11.1 - 2020-01-27

• Requires Hypothesis >= 5.3.0, for improved IP address strategies
• Better canoncialisation of array schemata

0.11.0 - 2020-01-26

• Resolve local, non-recursive references via the $ref keyword.

This is the largest feature in a while, and for some schemata it is a breaking change. It's also a fundamental part of the spec, so I'm OK with that!

Note that hypothesis-jsonschema will raise an explicit error rather than fetching a remote resource via URI. If think your tests really should hit the network, get in touch and we can discuss adding an off-by-default option for this.

0.10.3 - 2020-01-26

• Improved canonicalisation of conflicting minProperties and maxProperties
• Explictly reject draft-03 schemata, which are not supported
• More specific type annotations for from_schema
• Better performance for certain object schemata

0.10.2 - 2020-01-09

• enum schema now shrink to a minimal example rather than the first value listed. This also makes the internals more efficient in certain rare cases.
• Improved handling of bounded numeric sub-schemas

0.10.1 - 2019-12-28

• Improved handling of non-integer numeric schemas with multipleOf
• Improved handling of not in many common cases
• Improved handling of object schemas with dependencies on required keys
• Fixed cases where propertyNames bans a required key

0.10.0 - 2019-12-26

• Improved handling of numeric schemas, especially integer schemas with multipleOf.
• Bump the minimum version of Hypothesis to ensure that all users have the unique array bugfix from 0.9.12.
• Fixed a bug where array schemas with an array of items, additionalItems: false, and a maxItems larger than the number of allowed items would resolve to an invalid strategy.

0.9.13 - 2019-12-18

• Improved internal handling of schemas for arrays which must always be length-zero.

0.9.12 - 2019-12-01

• Fixed RFC 3339 strings generation. Thanks to Dmitry Dygalo for the patch!
• Fixed a bug where equal floats and ints could be generated in a unique array, even though JSONSchema considers 0 === 0.0 (though this may also require an upstream fix to work...)

0.9.11 - 2019-11-30

• Fixed a bug where objects which could have either zero or one properties would always be generated with zero.

0.9.10 - 2019-11-27

• Updated project metadata and development tooling
• Supported and tested on Python 3.8

0.9.9 - 2019-10-02

• Correct handling of {"items": [...], "uniqueItems": true"} schemas

0.9.8 - 2019-08-24

• Corrected handling of the "format" keyword with unknown values - custom values are allowed by the spec and should be treated as annotations (i.e. ignored).

0.9.7 - 2019-08-15

• Improved canonicalisation, especially for deeply nested schemas.

0.9.6 - 2019-08-02

• A performance optimisation for null and boolean schema, which relies on a bugfix in jsonschema >= 3.0.2.

0.9.5 - 2019-08-02

• Improved handling of the contains keyword for arrays

0.9.4 - 2019-07-01

• Improved canonicalisation and merging for a wide range of schemas, which as usual unlocks significant optimisations and performance improvements for cases where they apply.

0.9.3 - 2019-06-13

• Future-proofed canonicalisation of type key.

0.9.2 - 2019-05-23

• Better internal canonicalization, which makes current and future optimisations more widely applicable.
• Yet another fix, this time for negative zero and numeric bouds as floats with sub-integer precision. IEEE 754 is tricky, even with Hypothesis!
• Fixes handling of enum with elements disallowed by base schema, handling of if-then-else with a base schema, and handling of regex patterns that are invalid in Python.

0.9.1 - 2019-05-22

• Fix the fix for numeric schemas with multipleOf and exclusive bounds.

0.9.0 - 2019-05-21

• Supports merging schemas for overlapping patternProperties, a significant performance improvement in most cases.
• If the "type" key is missing, it is now inferred from other keys rather than always defaulting to "object".
• Fixed handling of complicated numeric bounds.

0.8.2 - 2019-05-21

• Improve performance for object schemas where the min and max size can be further constrained from properties and propertyNames attributes.

0.8.1 - 2019-03-24

• Supports draft-04 schemata with the latest version of jsonschema

0.8.0 - 2019-03-23

• Further improved support for allOf, oneOf, and anyOf with base schemata
• Added support for dependencies
• Handles overlapping patternProperties

0.7.0 - 2019-03-21

• Now requires jsonschema >= 3.0
• Improved support for allOf, oneOf, and propertyNames
• Supports schemata with "type": [an array of types]
• Warning-free on Hypothesis 4.11

0.6.1 - 2019-02-23

• Fix continuous delivery configuration (before the latent bug manifested)

0.6.0 - 2019-02-23

• Support for conditional subschemata, i.e. the if, then, else keywords, and the anyOf, allOf, oneOf, and not keywords.

0.5.0 - 2019-02-22

• Works with jsonschema 3.0 pre-release
• Initial support for draft06 and draft07

0.4.2 - 2019-02-14

• Dropped dependency on canonicaljson
• Less warnings on Python 3.7

0.4.1 - 2019-02-06

• Relicensed under the more permissive Mozilla Public License, like Hypothesis
• Requires Hypothesis version 4.0 or later
• Fixed an array bounds bug with maxItems and contains keywords

0.4.0 - 2018-11-25

Supports string formats (email, datetime, etc) and simple use of the "contains" keyword for arrays.

0.3.0 - 2018-11-25

Good support for all basic types. MVP.

0.2.0 - 2018-11-24

Inference for null, boolean, string, and numeric types.

0.1.0 - 2018-11-21

Stake in the ground (generate arbitrary JSON and filter it!)

Security contact information

To report a security vulnerability, please use the Tidelift security contact. Tidelift will coordinate the fix and disclosure.