stash/pkg/utils/oshash_internal_test.go

76 lines
1.7 KiB
Go

package utils
import (
"math/rand"
"testing"
)
// Note that the public API returns "" instead.
func TestOshashEmpty(t *testing.T) {
var size int64
head := make([]byte, chunkSize)
tail := make([]byte, chunkSize)
want := "0000000000000000"
got, err := oshash(size, head, tail)
if err != nil {
t.Errorf("TestOshashEmpty: Error from oshash: %v", err)
}
if got != want {
t.Errorf("TestOshashEmpty: oshash(0, 0, 0) = %q; want %q", got, want)
}
}
// As oshash sums byte values, causing collisions is trivial.
func TestOshashCollisions(t *testing.T) {
buf1 := []byte("this is dumb")
buf2 := []byte("dumb is this")
size := int64(len(buf1))
head := make([]byte, chunkSize)
tail1 := make([]byte, chunkSize)
copy(tail1[len(tail1)-len(buf1):], buf1)
hash1, err := oshash(size, head, tail1)
if err != nil {
t.Errorf("TestOshashCollisions: Error from oshash: %v", err)
}
tail2 := make([]byte, chunkSize)
copy(tail2[len(tail2)-len(buf2):], buf2)
hash2, err := oshash(size, head, tail2)
if err != nil {
t.Errorf("TestOshashCollisions: Error from oshash: %v", err)
}
if hash1 != hash2 {
t.Errorf("TestOshashCollisions: oshash(n, k, ... %v) =! oshash(n, k, ... %v)", buf1, buf2)
}
}
func BenchmarkOsHash(b *testing.B) {
src := rand.NewSource(9999)
r := rand.New(src)
size := int64(1234567890)
head := make([]byte, 1024*64)
_, err := r.Read(head)
if err != nil {
b.Errorf("unable to generate head array: %v", err)
}
tail := make([]byte, 1024*64)
_, err = r.Read(tail)
if err != nil {
b.Errorf("unable to generate tail array: %v", err)
}
b.ResetTimer()
for n := 0; n < b.N; n++ {
_, err := oshash(size, head, tail)
if err != nil {
b.Errorf("unexpected error: %v", err)
}
}
}