1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
|
// 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 runtime_test
import (
"math"
"strings"
"testing"
"unsafe"
)
var (
zero = math.Copysign(0, +1)
negZero = math.Copysign(0, -1)
inf = math.Inf(+1)
negInf = math.Inf(-1)
nan = math.NaN()
)
var tests = []struct{ min, max float64 }{
{1, 2},
{-2, 1},
{negZero, zero},
{zero, inf},
{negInf, zero},
{negInf, inf},
{1, inf},
{negInf, 1},
}
var all = []float64{1, 2, -1, -2, zero, negZero, inf, negInf, nan}
func eq(x, y float64) bool {
return x == y && math.Signbit(x) == math.Signbit(y)
}
func TestMinFloat(t *testing.T) {
for _, tt := range tests {
if z := min(tt.min, tt.max); !eq(z, tt.min) {
t.Errorf("min(%v, %v) = %v, want %v", tt.min, tt.max, z, tt.min)
}
if z := min(tt.max, tt.min); !eq(z, tt.min) {
t.Errorf("min(%v, %v) = %v, want %v", tt.max, tt.min, z, tt.min)
}
}
for _, x := range all {
if z := min(nan, x); !math.IsNaN(z) {
t.Errorf("min(%v, %v) = %v, want %v", nan, x, z, nan)
}
if z := min(x, nan); !math.IsNaN(z) {
t.Errorf("min(%v, %v) = %v, want %v", nan, x, z, nan)
}
}
}
func TestMaxFloat(t *testing.T) {
for _, tt := range tests {
if z := max(tt.min, tt.max); !eq(z, tt.max) {
t.Errorf("max(%v, %v) = %v, want %v", tt.min, tt.max, z, tt.max)
}
if z := max(tt.max, tt.min); !eq(z, tt.max) {
t.Errorf("max(%v, %v) = %v, want %v", tt.max, tt.min, z, tt.max)
}
}
for _, x := range all {
if z := max(nan, x); !math.IsNaN(z) {
t.Errorf("min(%v, %v) = %v, want %v", nan, x, z, nan)
}
if z := max(x, nan); !math.IsNaN(z) {
t.Errorf("min(%v, %v) = %v, want %v", nan, x, z, nan)
}
}
}
// testMinMax tests that min/max behave correctly on every pair of
// values in vals.
//
// vals should be a sequence of values in strictly ascending order.
func testMinMax[T int | uint8 | string](t *testing.T, vals ...T) {
for i, x := range vals {
for _, y := range vals[i+1:] {
if !(x < y) {
t.Fatalf("values out of order: !(%v < %v)", x, y)
}
if z := min(x, y); z != x {
t.Errorf("min(%v, %v) = %v, want %v", x, y, z, x)
}
if z := min(y, x); z != x {
t.Errorf("min(%v, %v) = %v, want %v", y, x, z, x)
}
if z := max(x, y); z != y {
t.Errorf("max(%v, %v) = %v, want %v", x, y, z, y)
}
if z := max(y, x); z != y {
t.Errorf("max(%v, %v) = %v, want %v", y, x, z, y)
}
}
}
}
func TestMinMaxInt(t *testing.T) { testMinMax[int](t, -7, 0, 9) }
func TestMinMaxUint8(t *testing.T) { testMinMax[uint8](t, 0, 1, 2, 4, 7) }
func TestMinMaxString(t *testing.T) { testMinMax[string](t, "a", "b", "c") }
// TestMinMaxStringTies ensures that min(a, b) returns a when a == b.
func TestMinMaxStringTies(t *testing.T) {
s := "xxx"
x := strings.Split(s, "")
test := func(i, j, k int) {
if z := min(x[i], x[j], x[k]); unsafe.StringData(z) != unsafe.StringData(x[i]) {
t.Errorf("min(x[%v], x[%v], x[%v]) = %p, want %p", i, j, k, unsafe.StringData(z), unsafe.StringData(x[i]))
}
if z := max(x[i], x[j], x[k]); unsafe.StringData(z) != unsafe.StringData(x[i]) {
t.Errorf("max(x[%v], x[%v], x[%v]) = %p, want %p", i, j, k, unsafe.StringData(z), unsafe.StringData(x[i]))
}
}
test(0, 1, 2)
test(0, 2, 1)
test(1, 0, 2)
test(1, 2, 0)
test(2, 0, 1)
test(2, 1, 0)
}
|
