Adds JSON Schema Draft 6/7 support

[artem-zakharchenko]

Contains backward-compatible changes that enable JSON Schema Draft 6/7 support (pre-requisite for OpenAPI support in Dredd).

Changelog

• Splits legacy (Amanda, TV4) and "future" AJV validators into separate classes
• Provides a master-class to determine a proper validator based on the JSON Schema explicit or implicit version
• Adjusts existing unit/integration test suites to align with the introduced changes
• FIX: Makes errors[n].location.property names consistent and validator-agnostic (property is not always an array that points to the deeply nested property, i.e. ['friends', 2, 'name'])
• Added a single point of coercion of arbitrary validation structure to Gavel-compliant validation structure (toGavelResults()) and respective unit tests

GitHub

• Closes Use ajv JSON Schema Validator #90

Roadmap

• Split legacy and next JSON Schema Draft versions validation into separate validator classes
• Provide a master class that would determine which validator class to use
• Resolve "schema with key or id already exists" during V6-7 validation with AJV
• Verify new schemas V6-7 are valid representations of their draft versions
• Discuss/Revert previously present implicit logic to waterfall attempts to validate a given JSON Schema without an explicit $schema version (first as V3, then as V4)
• Revert support of implicit JSON Schema version (fallback to V3 if no version is set via $schema property)
• Adjust derived JsonExample class to implement JsonSchemaValidator properly
• Adjust the usage surface of new JsonSchema()
  • validateBody
  • validateHeaders
• Adjust affected tests
  • test/unit/validators/json-schema.test
  • amanda-to-gavel-shared
  • TextDiff unit tests
  • validate integration tests
• Add new tests
  • Unit test to assert that amanda/tv4/ajv error format is coerced to Gavel-compliant format correctly
• Infer a JSON Schema Draft V7 if a given JSON Schema contains a single boolean value

[artem-zakharchenko]

Explicit error type to use in unit tests instead of asserting an exact message.

[artem-zakharchenko]

Overriding JsonSchemaValidator.validateSchema() to use TV4 to validate both V3 and V4 (copying previous implementation, refactored).

[artem-zakharchenko]

A wrapping class to determine which actual validator class to use. A temporary wrapper until we deprecate Amanda and TV4. Overkill: determines a JSON Schema's version twice (once in the wrapper class, another time in the actual validator class).

[artem-zakharchenko]

@kylef, please, do you mind giving my approach a look? I would like to verify my vision is optimal before I proceed. Also to make sure the valid/invalid schema versions I added are okay.

Thanks.

[artem-zakharchenko]

I've removed amanda-to-gavel-shared module entirely, since I've also removed evaluateOutputToResults(). Instead, JsonSchemaLegacy would use an internal method to coerce Amanda/TV4 result format to Gavel-compliant error format.

Since Gavel cannot accept Amanda/TV4 validation result as input, it's safe to remove and play around with these test suites. They are testing internal functionality.

I will add a new test suite to cover that the newly added method converts Amanda/TV4/AJV result format to Gavel-compliant error format properly as the next step.

[artem-zakharchenko]

Amanda produces prop[n] property, which appears to be invalid JSON pointer.

I've refactored the coercing logic so it produces ['fiends', 2, 'online'] JSON pointer format.

[artem-zakharchenko]

This would be considered a breaking change, but it's rather a bug fix, because it fixes an unexpected property format. It's expected to be a list of stings, and it was resolved to a plain string sometimes.

[artem-zakharchenko]

@kylef, could you please take a look at this pull request? It should be ready. Thanks 😊

[ApiaryBot]

🎉 This PR is included in version 8.2.0 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

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