package maths

import (
	"exp/bignum"
	"testing"
)

var dataBignum = map[uint] string {
  0 : "1" ,
  1 : "1" ,
  2 : "2" ,
  3 : "6" ,
  4 : "24" ,
  5 : "120" ,
  6 : "720" ,
  7 : "5040" ,
  8 : "40320" ,
  9 : "362880" ,
  10 : "3628800" ,
  11 : "39916800" ,
  12 : "479001600" ,
  13 : "6227020800" ,
  14 : "87178291200" ,
  20 : "2432902008176640000" ,
  30 : "265252859812191058636308480000000" ,
  40 : "815915283247897734345611269596115894272000000000" ,
}

func testFactorialBignumCorrectResults ( function func (uint) bignum.Natural , label string , t *testing.T ) {
	for parameter , expectedString := range dataBignum {
		expected , _ , _ := bignum.NatFromString ( expectedString , 10 )
		if actual := function ( parameter ) ; actual.Cmp ( expected ) != 0 {
			t.Errorf ( "%s of %d failed, expected %s, got %s\n" , label , parameter , expectedString , actual.ToString ( 10 ) )
		}
	}
}

func TestFactorialBignumCorrectIterative ( t *testing.T ) {
	testFactorialBignumCorrectResults ( factorial_bignum_iterative , "Iterative" , t )
}

func TestFactorialBignumCorrectRecursive ( t *testing.T ) {
	testFactorialBignumCorrectResults ( factorial_bignum_recursive , "Recursive" , t )
}

func TestFactorialBignumCorrectTailRecursive ( t *testing.T ) {
	testFactorialBignumCorrectResults ( factorial_bignum_tailRecursive , "Tail Recursive" , t )
}