ᯓ𝘁𝗿𝗮𝘃𝗲𝗿𝘀𝗮𝗯𝗹𝗲/𝗷𝘀𝗼𝗻-𝘀𝗰𝗵𝗲𝗺𝗮-𝘁𝗲𝘀𝘁

Testing utility that generates arbitrary, pseudorandom JSON Schema documents, powered by fast-check

       

     

Requirements

@traversable/json-schema-test has 1 peer dependency:

1. fast-check

Usage

$ pnpm add -D @traversable/json-schema-test fast-check
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Here's an example of importing the library:

import { JsonSchemaTest } from '@traversable/json-schema-test'

// see below for specifc examples
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Table of contents

• JsonSchemaTest.seedToSchema
• JsonSchemaTest.seedToValidData
• JsonSchemaTest.seedToInvalidData
• JsonSchemaTest.SeedGenerator
• JsonSchemaTest.SeedValidDataGenerator
• JsonSchemaTest.SeedInvalidDataGenerator

JsonSchemaTest.seedToSchema

Use JsonSchemaTest.seedToSchema to convert a seed generated by JsonSchemaTest.SeedGenerator into a JSON Schema schema that satisfies the configuration options you specified.

Example

import { JsonSchemaTest } from '@traversable/json-schema-test'
import * as fc from 'fast-check'

const builder = JsonSchemaTest.SeedGenerator()['*']
const [mySeed] = fc.sample(builder.object, 1)

const mySchema = JsonSchemaTest.seedToSchema(mySeed)
//    ^? const mySchema: JsonSchema
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JsonSchemaTest.seedToValidData

Use JsonSchemaTest.seedToValidData to convert a seed generated by JsonSchemaTest.SeedGenerator into data that satisfies the schema that the seed represents.

Example

import { JsonSchemaTest } from '@traversable/json-schema-test'
import * as fc from 'fast-check'

const builder = JsonSchemaTest.SeedGenerator()['*']
const [mySeed] = fc.sample(builder.object, 1)

const mySchema = JsonSchemaTest.seedToSchema(mySeed)
//    ^? const mySchema: JsonSchema

const validData = JsonSchemaTest.seedToValidData(mySeed)
//    ^? validated against `mySchema`, will always succeed
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JsonSchemaTest.seedToInvalidData

Use JsonSchemaTest.seedToInvalidData to convert a seed generated by JsonSchemaTest.SeedGenerator into data that does not satisfy the schema that the seed represents.

Example

import { JsonSchemaTest } from '@traversable/json-schema-test'
import * as fc from 'fast-check'

const builder = JsonSchemaTest.SeedGenerator()['*']
const [mySeed] = fc.sample(builder.object, 1)

const mySchema = JsonSchemaTest.seedToSchema(mySeed)
//    ^? const mySchema: JsonSchema.TSchema

const invalidData = JsonSchemaTest.seedToValidData(mySeed)
//    ^? validated against `mySchema`, will always fail
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JsonSchemaTest.SeedGenerator

Generates a configurable, pseudo-random "seed builder".

• Use JsonSchemaTest.seedToSchema to convert a seed into a JSON Schema
• Use JsonSchemaTest.seedToValidData to convert a seed into valid data
• Use JsonSchemaTest.seedToInvalidData to convert a seed into invalid data

Example

import { JsonSchemaTest, type JsonSchema } from '@traversable/json-schema-test'
import * as fc from 'fast-check'

const builder = JsonSchemaTest.SeedGenerator({
  include: ["boolean", "string", "object"],
  // 𐙘 use `include` to only include certain schema types
  exclude: ["boolean", "any"],
  // 𐙘 use `exclude` to exclude certain schema types altogether (overrides `include`)
  object: { maxKeys: 5 },
  // 𐙘 specific arbitraries are configurable by name
})

// included schemas are present as properties on your generator...
builder.string
builder.object

// ...excluded schemas are not present...
builder.boolean // 🚫 TypeError

// ...a special wildcard `"*"` property (pronounced "surprise me") is always present:
builder["*"]

/**
 * `fast-check` will generate a seed, which is a data structure containing
 * integers that represent a kind of AST.
 *
 * To use a seed, you need to pass it to an interpreter like `JsonSchemaTest.seedToSchema`,
 * `JsonSchemaTest.seedToValidData` or `JsonSchemaTest.seedToInvalidData`:
 */

const [mySeed] = fc.sample(builder.object, 1)

const mySchema = JsonSchemaTest.seedToSchema(mySeed)
//    ^? const mySchema: JsonSchema

const validData = JsonSchemaTest.seedToValidData(mySeed)
//    ^? since the `mySeed` was also used to generate `mySchema`,
//       parsing `validData` should always succeed

const invalidData = JsonSchemaTest.seedToInvalidData(mySeed)
//    ^? since the `mySeed` was also used to generate `mySchema`,
//       parsing `invalidData` should always fail
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JsonSchemaTest.SeedValidDataGenerator

Like JsonSchemaTest.SeedGenerator, except JsonSchemaTest.SeedValidDataGenerator comes pre-configured to exclude schemas that make it impossible to reliably generate valid data.

JsonSchemaTest.SeedInvalidDataGenerator

Like JsonSchemaTest.SeedGenerator, except JsonSchemaTest.SeedValidDataGenerator comes pre-configured to exclude schemas that make it impossible to reliably generate invalid data.