syncthing/lib/util/random_test.go

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// Copyright (C) 2014 The Syncthing Authors.
//
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// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this file,
// You can obtain one at http://mozilla.org/MPL/2.0/.
package util
import (
"runtime"
"sync"
"testing"
)
var predictableRandomTest sync.Once
func TestPredictableRandom(t *testing.T) {
if runtime.GOARCH != "amd64" {
t.Skip("Test only for 64 bit platforms; but if it works there, it should work on 32 bit")
}
predictableRandomTest.Do(func() {
// predictable random sequence is predictable
e := int64(3440579354231278675)
if v := int64(PredictableRandom.Int()); v != e {
t.Errorf("Unexpected random value %d != %d", v, e)
}
})
}
func TestSeedFromBytes(t *testing.T) {
// should always return the same seed for the same bytes
tcs := []struct {
bs []byte
v int64
}{
{[]byte("hello world"), -3639725434188061933},
{[]byte("hello worlx"), -2539100776074091088},
}
for _, tc := range tcs {
if v := SeedFromBytes(tc.bs); v != tc.v {
t.Errorf("Unexpected seed value %d != %d", v, tc.v)
}
}
}
func TestRandomString(t *testing.T) {
for _, l := range []int{0, 1, 2, 3, 4, 8, 42} {
s := RandomString(l)
if len(s) != l {
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t.Errorf("Incorrect length %d != %d", len(s), l)
}
}
strings := make([]string, 1000)
for i := range strings {
strings[i] = RandomString(8)
for j := range strings {
if i == j {
continue
}
if strings[i] == strings[j] {
t.Errorf("Repeated random string %q", strings[i])
}
}
}
}
func TestRandomInt64(t *testing.T) {
ints := make([]int64, 1000)
for i := range ints {
ints[i] = RandomInt64()
for j := range ints {
if i == j {
continue
}
if ints[i] == ints[j] {
t.Errorf("Repeated random int64 %d", ints[i])
}
}
}
}