import { interpolate } from './'

test('computes the midpoint of two numbers', () => {
  const interpolated = interpolate({ x: 0 }, { x: 10 }, 0.5)

  expect(5).toEqual(interpolated.x)
})

test('computes the midpoint of two token strings', () => {
  const interpolated = interpolate({ color: '#000' }, { color: '#fff' }, 0.5)

  expect('rgb(127,127,127)').toEqual(interpolated.color)
})

test('accounts for optional delay', () => {
  let interpolated = interpolate({ x: 0 }, { x: 10 }, 0.5, 'linear', 0.5)
  expect(interpolated.x).toEqual(0)

  interpolated = interpolate({ x: 0 }, { x: 10 }, 1.0, 'linear', 0.5)
  expect(interpolated.x).toEqual(5)

  interpolated = interpolate({ x: 0 }, { x: 10 }, 1.5, 'linear', 0.5)
  expect(interpolated.x).toEqual(10)
})

test('supports per-interpolation custom easing curves', () => {
  const easingFn = pos => pos * 2

  const interpolated = interpolate({ x: 0 }, { x: 10 }, 0.5, easingFn)
  expect(interpolated.x).toEqual(10)
})