ᯓ𝘁𝗿𝗮𝘃𝗲𝗿𝘀𝗮𝗯𝗹𝗲/𝗮𝗿𝗸𝘁𝘆𝗽𝗲-𝘁𝗲𝘀𝘁

Testing utility that generates arbitrary, pseudorandom arktype schemas, powered by fast-check

       

     

Requirements

@traversable/arktype-test has 2 peer dependencies:

1. arktype (v2.1)
2. fast-check

Usage

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

import { type } from 'arktype'
import { arkTest } from '@traversable/arktype-test'

// see below for specifc examples
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Table of contents

• arkTest.SeedGenerator
• arkTest.seedToSchema
• arkTest.seedToValidData
• arkTest.seedToInvalidData

arkTest.seedToSchema

Use arkTest.seedToSchema to convert a seed generated by arkTest.SeedGenerator into an ArkType schema that satisfies the configuration options you specified.

Example

import { type } from 'arktype'
import { arkTest } from '@traversable/arktype-test'
import * as fc from 'fast-check'

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

const mySchema = arkTest.seedToSchema(mySeed)
//    ^? const mySchema: type.Any
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arkTest.seedToValidData

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

Example

import { type } from 'arktype'
import { arkTest } from '@traversable/arktype-test'
import * as fc from 'fast-check'

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

const mySchema = arkTest.seedToSchema(mySeed)
//    ^? const mySchema: type.Any

const validData = arkTest.seedToValidData(mySeed)

mySchema(validData) instanceof type.errors // always `false`
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arkTest.seedToInvalidData

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

Example

import { type } from 'arktype'
import { arkTest } from '@traversable/arktype-test'
import * as fc from 'fast-check'

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

const mySchema = arkTest.seedToSchema(mySeed)
//    ^? const mySchema: type.Any

const invalidData = arkTest.seedToValidData(mySeed)

mySchema(invalidData) instanceof type.errors // always `true`
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arkTest.SeedGenerator

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

• Use arkTest.seedToSchema to convert a seed into an ArkType schema
• Use arkTest.seedToValidData to convert a seed into valid data
• Use arkTest.seedToInvalidData to convert a seed into invalid data

Example

import { type } from 'arktype'
import { arkTest } from '@traversable/arktype-test'
import * as fc from 'fast-check'

const builder = arkTest.SeedGenerator({
  include: ["boolean", "string", "object"],
  // 𐙘 use `include` to only include certain schema types
  exclude: ["boolean", "unknown"],
  // 𐙘 use `exclude` to exclude certain schema types altogether (overrides `include`)
  minDepth: 1,
  // 𐙘 use `minDepth` to control the schema's minimum depth
  //   **NOTE:** schemas can get very large!
  //   using in your CI/CD pipeline is _not_ recommended
  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 `arkTest.seedToSchema`,
 * `arkTest.seedToValidData` or `arkTest.seedToInvalidData`:
 */

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

const mySchema = arkTest.seedToSchema(mySeed)
//    ^? const mySchema: type.Any

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

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

arkTest.SeedGenerator has found several upstream bugs:

1. Array + tuple union unsatisfied by empty array

• Issue
• Sandbox

2. Discriminated union bug

• Issue
• Sandbox