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// Copyright 2022 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 slices
import (
"math"
"math/rand"
"sort"
"strconv"
"strings"
"testing"
)
var ints = [...]int{74, 59, 238, -784, 9845, 959, 905, 0, 0, 42, 7586, -5467984, 7586}
var float64s = [...]float64{74.3, 59.0, math.Inf(1), 238.2, -784.0, 2.3, math.Inf(-1), 9845.768, -959.7485, 905, 7.8, 7.8, 74.3, 59.0, math.Inf(1), 238.2, -784.0, 2.3}
var float64sWithNaNs = [...]float64{74.3, 59.0, math.Inf(1), 238.2, -784.0, 2.3, math.NaN(), math.NaN(), math.Inf(-1), 9845.768, -959.7485, 905, 7.8, 7.8}
var strs = [...]string{"", "Hello", "foo", "bar", "foo", "f00", "%*&^*&^&", "***"}
func TestSortIntSlice(t *testing.T) {
data := Clone(ints[:])
Sort(data)
if !IsSorted(data) {
t.Errorf("sorted %v", ints)
t.Errorf(" got %v", data)
}
}
func TestSortFuncIntSlice(t *testing.T) {
data := Clone(ints[:])
SortFunc(data, func(a, b int) bool { return a < b })
if !IsSorted(data) {
t.Errorf("sorted %v", ints)
t.Errorf(" got %v", data)
}
}
func TestSortFloat64Slice(t *testing.T) {
data := Clone(float64s[:])
Sort(data)
if !IsSorted(data) {
t.Errorf("sorted %v", float64s)
t.Errorf(" got %v", data)
}
}
func TestSortFloat64SliceWithNaNs(t *testing.T) {
data := float64sWithNaNs[:]
input := Clone(data)
// Make sure Sort doesn't panic when the slice contains NaNs.
Sort(data)
// Check whether the result is a permutation of the input.
sort.Float64s(data)
sort.Float64s(input)
for i, v := range input {
if data[i] != v && !(math.IsNaN(data[i]) && math.IsNaN(v)) {
t.Fatalf("the result is not a permutation of the input\ngot %v\nwant %v", data, input)
}
}
}
func TestSortStringSlice(t *testing.T) {
data := Clone(strs[:])
Sort(data)
if !IsSorted(data) {
t.Errorf("sorted %v", strs)
t.Errorf(" got %v", data)
}
}
func TestSortLarge_Random(t *testing.T) {
n := 1000000
if testing.Short() {
n /= 100
}
data := make([]int, n)
for i := 0; i < len(data); i++ {
data[i] = rand.Intn(100)
}
if IsSorted(data) {
t.Fatalf("terrible rand.rand")
}
Sort(data)
if !IsSorted(data) {
t.Errorf("sort didn't sort - 1M ints")
}
}
type intPair struct {
a, b int
}
type intPairs []intPair
// Pairs compare on a only.
func intPairLess(x, y intPair) bool {
return x.a < y.a
}
// Record initial order in B.
func (d intPairs) initB() {
for i := range d {
d[i].b = i
}
}
// InOrder checks if a-equal elements were not reordered.
func (d intPairs) inOrder() bool {
lastA, lastB := -1, 0
for i := 0; i < len(d); i++ {
if lastA != d[i].a {
lastA = d[i].a
lastB = d[i].b
continue
}
if d[i].b <= lastB {
return false
}
lastB = d[i].b
}
return true
}
func TestStability(t *testing.T) {
n, m := 100000, 1000
if testing.Short() {
n, m = 1000, 100
}
data := make(intPairs, n)
// random distribution
for i := 0; i < len(data); i++ {
data[i].a = rand.Intn(m)
}
if IsSortedFunc(data, intPairLess) {
t.Fatalf("terrible rand.rand")
}
data.initB()
SortStableFunc(data, intPairLess)
if !IsSortedFunc(data, intPairLess) {
t.Errorf("Stable didn't sort %d ints", n)
}
if !data.inOrder() {
t.Errorf("Stable wasn't stable on %d ints", n)
}
// already sorted
data.initB()
SortStableFunc(data, intPairLess)
if !IsSortedFunc(data, intPairLess) {
t.Errorf("Stable shuffled sorted %d ints (order)", n)
}
if !data.inOrder() {
t.Errorf("Stable shuffled sorted %d ints (stability)", n)
}
// sorted reversed
for i := 0; i < len(data); i++ {
data[i].a = len(data) - i
}
data.initB()
SortStableFunc(data, intPairLess)
if !IsSortedFunc(data, intPairLess) {
t.Errorf("Stable didn't sort %d ints", n)
}
if !data.inOrder() {
t.Errorf("Stable wasn't stable on %d ints", n)
}
}
func TestBinarySearch(t *testing.T) {
str1 := []string{"foo"}
str2 := []string{"ab", "ca"}
str3 := []string{"mo", "qo", "vo"}
str4 := []string{"ab", "ad", "ca", "xy"}
// slice with repeating elements
strRepeats := []string{"ba", "ca", "da", "da", "da", "ka", "ma", "ma", "ta"}
// slice with all element equal
strSame := []string{"xx", "xx", "xx"}
tests := []struct {
data []string
target string
wantPos int
wantFound bool
}{
{[]string{}, "foo", 0, false},
{[]string{}, "", 0, false},
{str1, "foo", 0, true},
{str1, "bar", 0, false},
{str1, "zx", 1, false},
{str2, "aa", 0, false},
{str2, "ab", 0, true},
{str2, "ad", 1, false},
{str2, "ca", 1, true},
{str2, "ra", 2, false},
{str3, "bb", 0, false},
{str3, "mo", 0, true},
{str3, "nb", 1, false},
{str3, "qo", 1, true},
{str3, "tr", 2, false},
{str3, "vo", 2, true},
{str3, "xr", 3, false},
{str4, "aa", 0, false},
{str4, "ab", 0, true},
{str4, "ac", 1, false},
{str4, "ad", 1, true},
{str4, "ax", 2, false},
{str4, "ca", 2, true},
{str4, "cc", 3, false},
{str4, "dd", 3, false},
{str4, "xy", 3, true},
{str4, "zz", 4, false},
{strRepeats, "da", 2, true},
{strRepeats, "db", 5, false},
{strRepeats, "ma", 6, true},
{strRepeats, "mb", 8, false},
{strSame, "xx", 0, true},
{strSame, "ab", 0, false},
{strSame, "zz", 3, false},
}
for _, tt := range tests {
t.Run(tt.target, func(t *testing.T) {
{
pos, found := BinarySearch(tt.data, tt.target)
if pos != tt.wantPos || found != tt.wantFound {
t.Errorf("BinarySearch got (%v, %v), want (%v, %v)", pos, found, tt.wantPos, tt.wantFound)
}
}
{
pos, found := BinarySearchFunc(tt.data, tt.target, strings.Compare)
if pos != tt.wantPos || found != tt.wantFound {
t.Errorf("BinarySearchFunc got (%v, %v), want (%v, %v)", pos, found, tt.wantPos, tt.wantFound)
}
}
})
}
}
func TestBinarySearchInts(t *testing.T) {
data := []int{20, 30, 40, 50, 60, 70, 80, 90}
tests := []struct {
target int
wantPos int
wantFound bool
}{
{20, 0, true},
{23, 1, false},
{43, 3, false},
{80, 6, true},
}
for _, tt := range tests {
t.Run(strconv.Itoa(tt.target), func(t *testing.T) {
{
pos, found := BinarySearch(data, tt.target)
if pos != tt.wantPos || found != tt.wantFound {
t.Errorf("BinarySearch got (%v, %v), want (%v, %v)", pos, found, tt.wantPos, tt.wantFound)
}
}
{
cmp := func(a, b int) int {
return a - b
}
pos, found := BinarySearchFunc(data, tt.target, cmp)
if pos != tt.wantPos || found != tt.wantFound {
t.Errorf("BinarySearchFunc got (%v, %v), want (%v, %v)", pos, found, tt.wantPos, tt.wantFound)
}
}
})
}
}
func TestBinarySearchFunc(t *testing.T) {
data := []int{1, 10, 11, 2} // sorted lexicographically
cmp := func(a int, b string) int {
return strings.Compare(strconv.Itoa(a), b)
}
pos, found := BinarySearchFunc(data, "2", cmp)
if pos != 3 || !found {
t.Errorf("BinarySearchFunc(%v, %q, cmp) = %v, %v, want %v, %v", data, "2", pos, found, 3, true)
}
}