1 package puddle
2
3 import (
4 "math"
5 "math/rand"
6 "testing"
7 "time"
8
9 "github.com/stretchr/testify/require"
10 )
11
12 func TestLog2Uint(t *testing.T) {
13 r := require.New(t)
14
15 r.Equal(uint8(0), log2Int(1))
16 r.Equal(uint8(0), log2Int[uint64](1))
17 r.Equal(uint8(1), log2Int[uint32](2))
18 r.Equal(uint8(7), log2Int[uint8](math.MaxUint8))
19 r.Equal(uint8(15), log2Int[uint16](math.MaxUint16))
20 r.Equal(uint8(31), log2Int[uint32](math.MaxUint32))
21 r.Equal(uint8(63), log2Int[uint64](math.MaxUint64))
22
23 r.Panics(func() { log2Int[uint64](0) })
24 r.Panics(func() { log2Int[int64](-1) })
25 }
26
27 func FuzzLog2Uint(f *testing.F) {
28 const cnt = 1000
29
30 rand := rand.New(rand.NewSource(time.Now().UnixNano()))
31 for i := 0; i < cnt; i++ {
32 val := uint64(rand.Int63())
33
34 f.Add(val + 1)
35 }
36
37 f.Fuzz(func(t *testing.T, val uint64) {
38 var mx uint8
39 for i := 63; i >= 0; i-- {
40 mask := uint64(1) << i
41 if mask&val != 0 {
42 mx = uint8(i)
43 break
44 }
45 }
46
47 require.Equal(t, mx, log2Int(val))
48 })
49 }
50
View as plain text