picomath/test/_picomath.js

import assert from 'assert'
import math from '../picomath.js'

describe('The default full picomath instance "math"', () => {
   it('performs basic arithmetic operations', () => {
      assert.strictEqual(math.subtract(16, math.add(3,4,2)), 7)
      assert.strictEqual(math.negate(math.number('8')), -8)
   })

   it('can be extended', () => {
      math('add', [args => typeof args[0] === 'string',
         (...addends) => addends.reduce((x,y) => x+y, '')])
      assert.strictEqual(math.add('Kilroy',' is here'), 'Kilroy is here')
   })

   it('handles complex numbers', () => {
      assert.deepStrictEqual(math.complex(2,3), {re: 2, im: 3})
      assert.deepStrictEqual(
         math.subtract(16, math.add(3, math.complex(0,4), 2)),
         math.complex(11, -4))
      assert.deepStrictEqual(math.negate(math.complex(3, '8')).im, -8)
   })

   it('does not double-define subtract', () => {
      assert.deepStrictEqual(math.subtract.imps.length, 1)
   })
})