import assert from 'assert'
import math from '../../../../src/defaultInstance.js'

describe('re', function () {
  it('should return the real part of a complex number', function () {
    assert.strictEqual(math.re(math.complex(2, 3)), 2)
    assert.strictEqual(math.re(math.complex(-2, -3)), -2)
    assert.strictEqual(math.re(math.i), 0)
  })

  it('should return the real part of a real number', function () {
    assert.strictEqual(math.re(2), 2)
  })

  it('should return the real part of a big number', function () {
    assert.deepStrictEqual(math.re(math.bignumber(2)), math.bignumber(2))
  })

  it('should return the real part of a boolean', function () {
    assert.strictEqual(math.re(true), 1)
    assert.strictEqual(math.re(false), 0)
  })

  it('should return the real part for each element in a matrix', function () {
    assert.deepStrictEqual(math.re([2, math.complex('3-6i')]), [2, 3])
    assert.deepStrictEqual(math.re(math.matrix([2, math.complex('3-6i')])).valueOf(), [2, 3])
  })

  it('should throw an error when called with an unsupported type of argument', function () {
    assert.throws(function () { math.re(new Date()) }, /TypeError: Unexpected type of argument/)
    assert.throws(function () { math.re(math.unit('5cm')) }, /TypeError: Unexpected type of argument/)
  })

  it('should throw an error in case of invalid number of arguments', function () {
    assert.throws(function () { math.re() }, /TypeError: Too few arguments/)
    assert.throws(function () { math.re(1, 2) }, /TypeError: Too many arguments/)
  })

  it('should LaTeX re', function () {
    const expression = math.parse('re(1+i)')
    assert.strictEqual(expression.toTex(), '\\Re\\left\\lbrace1+ i\\right\\rbrace')
  })
})