text: import assert from 'assert'
  import math from '../../../../src/defaultInstance.js'
  import approx from '../../../../tools/approx.js'
  const pi = math.pi
  const complex = math.complex
  const matrix = math.matrix
  const unit = math.unit
  const tanh = math.tanh
  const bigmath = math.create({ number: 'BigNumber', precision: 20 })
  
  describe('tanh', function () {
    it('should return the tanh of a boolean', function () {
      approx.equal(tanh(true), 0.76159415595576)
      approx.equal(tanh(false), 0)
    })
  
    it('should return the tanh of a number', function () {
      approx.equal(tanh(0), 0)
      approx.equal(tanh(pi), 0.99627207622075)
      approx.equal(tanh(1), 0.76159415595576)
      approx.equal(tanh(2), 0.96402758007582)
      approx.equal(tanh(3), 0.99505475368673)
    })
  
    it('should return the tanh of a bignumber', function () {
      const tanhBig = bigmath.tanh
      const Big = bigmath.bignumber
  
      const arg1 = Big(-Infinity)
      const arg2 = Big(-3)
      const arg10 = Big(Infinity)
      assert.deepStrictEqual(tanhBig(arg1), Big(-1))
      assert.deepStrictEqual(tanhBig(arg2), Big('-0.99505475368673045133'))
      assert.deepStrictEqual(tanhBig(Big(-2)), Big('-0.96402758007581688395'))
      assert.deepStrictEqual(tanhBig(Big(-1)), Big('-0.76159415595576488812'))
      assert.deepStrictEqual(tanhBig(Big(0)), Big(0))
      assert.deepStrictEqual(tanhBig(Big(1)), Big('0.76159415595576488812'))
      assert.deepStrictEqual(tanhBig(Big(2)), Big('0.96402758007581688395'))
      assert.deepStrictEqual(tanhBig(Big(3)), Big('0.99505475368673045133'))
      assert.deepStrictEqual(tanhBig(bigmath.pi).toString(), '0.99627207622074994426')
      assert.deepStrictEqual(tanhBig(arg10), Big(1))
  
      // Make sure args were not changed
      assert.deepStrictEqual(arg1.toString(), '-Infinity')
      assert.deepStrictEqual(arg2, Big(-3))
      assert.deepStrictEqual(arg10.toString(), 'Infinity')
    })
  
    it('should return the tanh of a complex number', function () {
      approx.deepEqual(tanh(complex('1')), complex(0.76159415595576, 0))
      approx.deepEqual(tanh(complex('i')), complex(0, 1.5574077246549))
      approx.deepEqual(tanh(complex('2 + i')), complex(1.0147936161466, 0.033812826079897))
    })
  
    it('should return the tanh of an angle', function () {
      approx.equal(tanh(unit('90deg')), 0.91715233566727)
      approx.equal(tanh(unit('-45deg')), -0.65579420263267)
  
      assert(math.isBigNumber(tanh(unit(math.bignumber(90), 'deg'))))
      approx.equal(tanh(unit(math.bignumber(90), 'deg')).toNumber(), 0.91715233566727)
  
      approx.deepEqual(tanh(unit(complex('2 + i'), 'rad')), complex(1.0147936161466, 0.033812826079897))
    })
  
    it('should throw an error if called with an invalid unit', function () {
      assert.throws(function () { tanh(unit('5 celsius')) })
    })
  
    it('should throw an error if called with a string', function () {
      assert.throws(function () { tanh('string') })
    })
  
    const tanh123 = [0.76159415595576, 0.96402758007582, 0.99505475368673]
  
    it('should return the tanh of each element of an array', function () {
      approx.deepEqual(tanh([1, 2, 3]), tanh123)
    })
  
    it('should return the tanh of each element of a matrix', function () {
      approx.deepEqual(tanh(matrix([1, 2, 3])), matrix(tanh123))
    })
  
    it('should throw an error in case of invalid number of arguments', function () {
      assert.throws(function () { tanh() }, /TypeError: Too few arguments/)
      assert.throws(function () { tanh(1, 2) }, /TypeError: Too many arguments/)
    })
  
    it('should LaTeX tanh', function () {
      const expression = math.parse('tanh(1)')
      assert.strictEqual(expression.toTex(), '\\tanh\\left(1\\right)')
    })
  })
  