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

function assertFalse (val) {
  assert(!val)
}

describe('symbolicEqual', function () {
  it('relates anything to itself', function () {
    assert(math.symbolicEqual('x', 'x'))
    assert(math.symbolicEqual('foo(x)', 'foo(x)'))
  })

  it('does not relate different variables', function () {
    assertFalse(math.symbolicEqual('x', 'y'))
    assertFalse(math.symbolicEqual('foo(x)+bar(x)', 'foo(x)+bar(y)'))
  })

  it('handles various manipulations', function () {
    assert(math.symbolicEqual('3x', 'x*3'))
    assert(math.symbolicEqual('x*y', 'y*x'))
    assert(math.symbolicEqual('x*y^2', 'y*x*y'))
    assert(math.symbolicEqual('x*(2y - y -y)', '0*z'))
  })

  it('responds to context', function () {
    assertFalse(math.symbolicEqual(
      'x*y', 'y*x', { context: { multiply: { commutative: false } } }))
    assert(math.symbolicEqual(
      'abs(x)', 'x', { context: math.simplify.positiveContext }))
  })
})