text: const assert = require('assert')
  const approx = require('../../../tools/approx')
  const math = require('../../../src/main')
  const BigNumber = math.type.BigNumber
  const Complex = math.type.Complex
  const DenseMatrix = math.type.DenseMatrix
  const Unit = math.type.Unit
  const median = math.median
  
  describe('median', function () {
    it('should return the median of an even number of numbers', function () {
      assert.equal(median(3, 1), 2)
      assert.equal(median(1, 3), 2)
      approx.equal(median(1, 3, 5, 2), 2.5)
      assert.equal(median(0, 0, 0, 0), 0)
    })
  
    it('should return the median of an odd number of numbers', function () {
      assert.equal(median(0), 0)
      assert.equal(median(5), 5)
      approx.equal(median(1, 3, 5, 2, -1), 2)
      assert.equal(median(0, 0, 0), 0)
    })
  
    it('should return the median of an even number of new BigNumbers', function () {
      assert.deepEqual(median(new BigNumber(1), new BigNumber(4), new BigNumber(5), new BigNumber(2)),
        new BigNumber(3))
    })
  
    it('should return the median of an odd number of new BigNumbers', function () {
      assert.deepEqual(median(new BigNumber(1), new BigNumber(4), new BigNumber(2)),
        new BigNumber(2))
    })
  
    it('should return the median of an even number of booleans', function () {
      assert.strictEqual(median(true, true, false, false), 0.5)
    })
  
    it('should return the median of an odd number of booleans', function () {
      assert.strictEqual(median(true, true, false), 1)
    })
  
    it('should return the median from an array', function () {
      assert.equal(median([1, 3, 5, 2, -5]), 2)
    })
  
    it('should return the median of units', function () {
      assert.deepEqual(median([new Unit(5, 'mm'), new Unit(15, 'mm'), new Unit(10, 'mm')]), new Unit(10, 'mm'))
      assert.deepEqual(median([new Unit(5, 'mm'), new Unit(30, 'mm'), new Unit(20, 'mm'), new Unit(10, 'mm')]), new Unit(15, 'mm'))
    })
  
    it('should return the median from an 1d matrix', function () {
      assert.equal(median(new DenseMatrix([1, 3, 5, 2, -5])), 2)
    })
  
    it('should return the median from a 2d array', function () {
      approx.equal(median([
        [1, 4, 7],
        [3, 0, 5]
      ]), 3.5)
    })
  
    it('should return the median from a 2d matrix', function () {
      approx.equal(median(new DenseMatrix([
        [1, 4, 7],
        [3, 0, 5]
      ])), 3.5)
    })
  
    it('should throw an error if called with invalid number of arguments', function () {
      assert.throws(function () { median() })
      assert.throws(function () { median([], 2, 3) })
    })
  
    it('should throw an error when called multiple arrays or matrices', function () {
      assert.throws(function () { median([1, 2], [3, 4]) }, /Scalar values expected/)
      assert.throws(function () { median(math.matrix([1, 2]), math.matrix([3, 4])) }, /Scalar values expected/)
    })
  
    it('should throw an error if called with not yet supported argument dim', function () {
      assert.throws(function () { median([], 2) }, /not yet supported/)
    })
  
    it('should throw an error if called with invalid type of arguments', function () {
      assert.throws(function () { median(2, new Complex(2, 5)) }, /TypeError: Cannot calculate median, no ordering relation is defined for complex numbers/)
      assert.throws(function () { median(new Complex(2, 3), new Complex(2, 1)) }, /TypeError: Cannot calculate median, no ordering relation is defined for complex numbers/)
  
      assert.throws(function () { median([[2, undefined, 4]]) }, /TypeError: Cannot calculate median, unexpected type of argument/)
      assert.throws(function () { median([[2, new Date(), 4]]) }, /TypeError: Cannot calculate median, unexpected type of argument/)
      assert.throws(function () { median([2, null, 4]) }, /TypeError: Cannot calculate median, unexpected type of argument/)
    })
  
    it('should throw an error if called with an empty array', function () {
      assert.throws(function () { median([]) })
    })
  
    it('should not mutate the input', function () {
      const a = [3, 2, 1]
      const b = median(a)
      assert.deepEqual(a, [3, 2, 1])
      assert.deepEqual(b, 2)
    })
  
    it('should LaTeX median', function () {
      const expression = math.parse('median(1,2,3,4)')
      assert.equal(expression.toTex(), '\\mathrm{median}\\left(1,2,3,4\\right)')
    })
  })
  