src/internal/strconv/decimal_test.go

// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package strconv_test

import (
	. "internal/strconv"
	"testing"
)

type shiftTest struct {
	i     uint64
	shift int
	out   string
}

var shifttests = []shiftTest{
	{0, -100, "0"},
	{0, 100, "0"},
	{1, 100, "1267650600228229401496703205376"},
	{1, -100,
		"0.00000000000000000000000000000078886090522101180541" +
			"17285652827862296732064351090230047702789306640625",
	},
	{12345678, 8, "3160493568"},
	{12345678, -8, "48225.3046875"},
	{195312, 9, "99999744"},
	{1953125, 9, "1000000000"},
}

func TestDecimalShift(t *testing.T) {
	for i := 0; i < len(shifttests); i++ {
		test := &shifttests[i]
		d := NewDecimal(test.i)
		d.Shift(test.shift)
		s := d.String()
		if s != test.out {
			t.Errorf("Decimal %v << %v = %v, want %v",
				test.i, test.shift, s, test.out)
		}
	}
}

type roundTest struct {
	i               uint64
	nd              int
	down, round, up string
	int             uint64
}

var roundtests = []roundTest{
	{0, 4, "0", "0", "0", 0},
	{12344999, 4, "12340000", "12340000", "12350000", 12340000},
	{12345000, 4, "12340000", "12340000", "12350000", 12340000},
	{12345001, 4, "12340000", "12350000", "12350000", 12350000},
	{23454999, 4, "23450000", "23450000", "23460000", 23450000},
	{23455000, 4, "23450000", "23460000", "23460000", 23460000},
	{23455001, 4, "23450000", "23460000", "23460000", 23460000},

	{99994999, 4, "99990000", "99990000", "100000000", 99990000},
	{99995000, 4, "99990000", "100000000", "100000000", 100000000},
	{99999999, 4, "99990000", "100000000", "100000000", 100000000},

	{12994999, 4, "12990000", "12990000", "13000000", 12990000},
	{12995000, 4, "12990000", "13000000", "13000000", 13000000},
	{12999999, 4, "12990000", "13000000", "13000000", 13000000},
}

func TestDecimalRound(t *testing.T) {
	for i := 0; i < len(roundtests); i++ {
		test := &roundtests[i]
		d := NewDecimal(test.i)
		d.RoundDown(test.nd)
		s := d.String()
		if s != test.down {
			t.Errorf("Decimal %v RoundDown %d = %v, want %v",
				test.i, test.nd, s, test.down)
		}
		d = NewDecimal(test.i)
		d.Round(test.nd)
		s = d.String()
		if s != test.round {
			t.Errorf("Decimal %v Round %d = %v, want %v",
				test.i, test.nd, s, test.down)
		}
		d = NewDecimal(test.i)
		d.RoundUp(test.nd)
		s = d.String()
		if s != test.up {
			t.Errorf("Decimal %v RoundUp %d = %v, want %v",
				test.i, test.nd, s, test.up)
		}
	}
}

type roundIntTest struct {
	i     uint64
	shift int
	int   uint64
}

var roundinttests = []roundIntTest{
	{0, 100, 0},
	{512, -8, 2},
	{513, -8, 2},
	{640, -8, 2},
	{641, -8, 3},
	{384, -8, 2},
	{385, -8, 2},
	{383, -8, 1},
	{1, 100, 1<<64 - 1},
	{1000, 0, 1000},
}

func TestDecimalRoundedInteger(t *testing.T) {
	for i := 0; i < len(roundinttests); i++ {
		test := roundinttests[i]
		d := NewDecimal(test.i)
		d.Shift(test.shift)
		int := d.RoundedInteger()
		if int != test.int {
			t.Errorf("Decimal %v >> %v RoundedInteger = %v, want %v",
				test.i, test.shift, int, test.int)
		}
	}
}