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Function: testFunctorLaws()

testFunctorLaws<F, A>(config): void

Defined in: testing/laws/functor.ts:62

Test that a functor implementation satisfies functor laws.

This function generates test suites that verify:

  • Identity law: map(fa, x => x) === fa
  • Composition law: map(map(fa, f), g) === map(fa, x => g(f(x)))

Type Parameters​

F​

F

A​

A

Parameters​

config​

FunctorLawConfig<F, A>

Configuration specifying the functor and test cases

Returns​

void

Example​

import { testFunctorLaws } from 'receta-test/laws'
import { ok } from 'receta/result'
import * as Result from 'receta/result'

describe('Result', () => {
  testFunctorLaws({
    type: 'Result',
    of: ok,
    map: Result.map,
    testCases: [
      { value: 5, transforms: [x => x * 2, x => x + 1] },
      { value: 'hello', transforms: [s => s.toUpperCase(), s => s.length] }
    ]
  })
})