// test approx itself...
import assert from 'assert'

import approx from '../../tools/approx.js'

describe('approx', function () {
  it('should test equality of positive values', function () {
    approx.equal(1 / 3, 0.33333333)
    approx.equal(2, 2.000001)
    approx.equal(2, 1.999999)
    assert.throws(function () { approx.equal(2, 2.001) }, assert.AssertionError)
    assert.throws(function () { approx.equal(2, 1.999) }, assert.AssertionError)
  })

  it('should test equality of negative values', function () {
    approx.equal(-2, -2.000001)
    approx.equal(-2, -1.999999)
    assert.throws(function () { approx.equal(-2, -2.001) }, assert.AssertionError)
    assert.throws(function () { approx.equal(-2, -1.999) }, assert.AssertionError)
  })

  it('should test equality of very large values', function () {
    approx.equal(2e100, 2.000001e100)
    approx.equal(2e100, 1.999999e100)
    assert.throws(function () { approx.equal(2e100, 2.001e100) }, assert.AssertionError)
    assert.throws(function () { approx.equal(2e100, 1.999e100) }, assert.AssertionError)
  })

  it('should test equality of very small values', function () {
    approx.equal(2e-100, 2.000001e-100)
    approx.equal(2e-100, 1.999999e-100)
    assert.throws(function () { approx.equal(2e-100, 2.001e-100) }, assert.AssertionError)
    assert.throws(function () { approx.equal(2e-100, 1.999e-100) }, assert.AssertionError)
  })

  it('should test equality of NaN numbers', function () {
    // NaN values
    const a = NaN
    const b = NaN
    approx.equal(a, b)
    assert.throws(function () { approx.equal(NaN, 3) }, assert.AssertionError)
    assert.throws(function () { approx.equal(NaN, 'nonumber') }, assert.AssertionError)
  })

  it('should test equality when one of the values is zero', function () {
    // zero as one of the two values
    approx.equal(0, 1e-15)
    approx.equal(1e-15, 0)
    assert.throws(function () { approx.equal(0, 0.001) }, assert.AssertionError)
  })

  // TODO: test approx.equal for (mixed) numbers, BigNumbers, Fractions, Complex numbers

  it('should test deep equality of arrays and objects', function () {
    approx.deepEqual({
      a: [1, 2, 3],
      b: [{ c: 4, d: 5 }]
    }, {
      a: [1.000001, 1.99999999, 3.000005],
      b: [{ c: 3.999999981, d: 5.0000023 }]
    })

    assert.throws(function () {
      approx.deepEqual({
        a: [1, 2, 3],
        b: [{ c: 4, d: 5 }]
      }, {
        a: [1.000001, 1.99999999, 3.000005],
        b: [{ c: 3.1, d: 5.0000023 }]
      })
    }, assert.AssertionError)

    assert.throws(function () {
      approx.deepEqual({
        a: [1, 2, 3],
        b: [{ c: 4, d: 5 }]
      }, {
        a: [1.001, 1.99999999, 3.000005],
        b: [{ c: 3, d: 5.0000023 }]
      })
    }, assert.AssertionError)
  })
})