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// Copyright 2023 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 cmp_test
import (
"cmp"
"fmt"
"math"
"slices"
"sort"
"testing"
"unsafe"
)
var negzero = math.Copysign(0, -1)
var nonnilptr uintptr = uintptr(unsafe.Pointer(&negzero))
var nilptr uintptr = uintptr(unsafe.Pointer(nil))
var tests = []struct {
x, y any
compare int
}{
{1, 2, -1},
{1, 1, 0},
{2, 1, +1},
{"a", "aa", -1},
{"a", "a", 0},
{"aa", "a", +1},
{1.0, 1.1, -1},
{1.1, 1.1, 0},
{1.1, 1.0, +1},
{math.Inf(1), math.Inf(1), 0},
{math.Inf(-1), math.Inf(-1), 0},
{math.Inf(-1), 1.0, -1},
{1.0, math.Inf(-1), +1},
{math.Inf(1), 1.0, +1},
{1.0, math.Inf(1), -1},
{math.NaN(), math.NaN(), 0},
{0.0, math.NaN(), +1},
{math.NaN(), 0.0, -1},
{math.NaN(), math.Inf(-1), -1},
{math.Inf(-1), math.NaN(), +1},
{0.0, 0.0, 0},
{negzero, negzero, 0},
{negzero, 0.0, 0},
{0.0, negzero, 0},
{negzero, 1.0, -1},
{negzero, -1.0, +1},
{nilptr, nonnilptr, -1},
{nonnilptr, nilptr, 1},
{nonnilptr, nonnilptr, 0},
}
func TestLess(t *testing.T) {
for _, test := range tests {
var b bool
switch test.x.(type) {
case int:
b = cmp.Less(test.x.(int), test.y.(int))
case string:
b = cmp.Less(test.x.(string), test.y.(string))
case float64:
b = cmp.Less(test.x.(float64), test.y.(float64))
case uintptr:
b = cmp.Less(test.x.(uintptr), test.y.(uintptr))
}
if b != (test.compare < 0) {
t.Errorf("Less(%v, %v) == %t, want %t", test.x, test.y, b, test.compare < 0)
}
}
}
func TestCompare(t *testing.T) {
for _, test := range tests {
var c int
switch test.x.(type) {
case int:
c = cmp.Compare(test.x.(int), test.y.(int))
case string:
c = cmp.Compare(test.x.(string), test.y.(string))
case float64:
c = cmp.Compare(test.x.(float64), test.y.(float64))
case uintptr:
c = cmp.Compare(test.x.(uintptr), test.y.(uintptr))
}
if c != test.compare {
t.Errorf("Compare(%v, %v) == %d, want %d", test.x, test.y, c, test.compare)
}
}
}
func TestSort(t *testing.T) {
// Test that our comparison function is consistent with
// sort.Float64s.
input := []float64{1.0, 0.0, negzero, math.Inf(1), math.Inf(-1), math.NaN()}
sort.Float64s(input)
for i := 0; i < len(input)-1; i++ {
if cmp.Less(input[i+1], input[i]) {
t.Errorf("Less sort mismatch at %d in %v", i, input)
}
if cmp.Compare(input[i], input[i+1]) > 0 {
t.Errorf("Compare sort mismatch at %d in %v", i, input)
}
}
}
func TestOr(t *testing.T) {
cases := []struct {
in []int
want int
}{
{nil, 0},
{[]int{0}, 0},
{[]int{1}, 1},
{[]int{0, 2}, 2},
{[]int{3, 0}, 3},
{[]int{4, 5}, 4},
{[]int{0, 6, 7}, 6},
}
for _, tc := range cases {
if got := cmp.Or(tc.in...); got != tc.want {
t.Errorf("cmp.Or(%v) = %v; want %v", tc.in, got, tc.want)
}
}
}
func ExampleOr() {
// Suppose we have some user input
// that may or may not be an empty string
userInput1 := ""
userInput2 := "some text"
fmt.Println(cmp.Or(userInput1, "default"))
fmt.Println(cmp.Or(userInput2, "default"))
fmt.Println(cmp.Or(userInput1, userInput2, "default"))
// Output:
// default
// some text
// some text
}
func ExampleOr_sort() {
type Order struct {
Product string
Customer string
Price float64
}
orders := []Order{
{"foo", "alice", 1.00},
{"bar", "bob", 3.00},
{"baz", "carol", 4.00},
{"foo", "alice", 2.00},
{"bar", "carol", 1.00},
{"foo", "bob", 4.00},
}
// Sort by customer first, product second, and last by higher price
slices.SortFunc(orders, func(a, b Order) int {
return cmp.Or(
cmp.Compare(a.Customer, b.Customer),
cmp.Compare(a.Product, b.Product),
cmp.Compare(b.Price, a.Price),
)
})
for _, order := range orders {
fmt.Printf("%s %s %.2f\n", order.Product, order.Customer, order.Price)
}
// Output:
// foo alice 2.00
// foo alice 1.00
// bar bob 3.00
// foo bob 4.00
// bar carol 1.00
// baz carol 4.00
}
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