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116 lines
2.4 KiB
116 lines
2.4 KiB
package rand
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import (
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"bytes"
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"encoding/json"
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"fmt"
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mrand "math/rand"
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"sync"
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"testing"
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"time"
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"github.com/stretchr/testify/assert"
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)
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func TestRandStr(t *testing.T) {
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l := 243
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s := RandStr(l)
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assert.Equal(t, l, len(s))
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}
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func TestRandBytes(t *testing.T) {
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l := 243
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b := RandBytes(l)
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assert.Equal(t, l, len(b))
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}
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func TestRandIntn(t *testing.T) {
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n := 243
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for i := 0; i < 100; i++ {
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x := RandIntn(n)
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assert.True(t, x < n)
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}
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}
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// Test to make sure that we never call math.rand().
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// We do this by ensuring that outputs are deterministic.
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func TestDeterminism(t *testing.T) {
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var firstOutput string
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// Set math/rand's seed for the sake of debugging this test.
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// (It isn't strictly necessary).
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mrand.Seed(1)
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for i := 0; i < 100; i++ {
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output := testThemAll()
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if i == 0 {
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firstOutput = output
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} else if firstOutput != output {
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t.Errorf("run #%d's output was different from first run.\nfirst: %v\nlast: %v",
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i, firstOutput, output)
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}
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}
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}
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func testThemAll() string {
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// Such determinism.
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grand.reset(1)
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// Use it.
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out := new(bytes.Buffer)
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perm := RandPerm(10)
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blob, _ := json.Marshal(perm)
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fmt.Fprintf(out, "perm: %s\n", blob)
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fmt.Fprintf(out, "randInt: %d\n", RandInt())
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fmt.Fprintf(out, "randUint: %d\n", RandUint())
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fmt.Fprintf(out, "randIntn: %d\n", RandIntn(97))
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fmt.Fprintf(out, "randInt31: %d\n", RandInt31())
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fmt.Fprintf(out, "randInt32: %d\n", RandInt32())
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fmt.Fprintf(out, "randInt63: %d\n", RandInt63())
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fmt.Fprintf(out, "randInt64: %d\n", RandInt64())
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fmt.Fprintf(out, "randUint32: %d\n", RandUint32())
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fmt.Fprintf(out, "randUint64: %d\n", RandUint64())
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return out.String()
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}
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func TestRngConcurrencySafety(t *testing.T) {
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var wg sync.WaitGroup
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for i := 0; i < 100; i++ {
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wg.Add(1)
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go func() {
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defer wg.Done()
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_ = RandUint64()
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<-time.After(time.Millisecond * time.Duration(RandIntn(100)))
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_ = RandPerm(3)
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}()
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}
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wg.Wait()
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}
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func BenchmarkRandBytes10B(b *testing.B) {
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benchmarkRandBytes(b, 10)
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}
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func BenchmarkRandBytes100B(b *testing.B) {
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benchmarkRandBytes(b, 100)
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}
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func BenchmarkRandBytes1KiB(b *testing.B) {
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benchmarkRandBytes(b, 1024)
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}
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func BenchmarkRandBytes10KiB(b *testing.B) {
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benchmarkRandBytes(b, 10*1024)
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}
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func BenchmarkRandBytes100KiB(b *testing.B) {
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benchmarkRandBytes(b, 100*1024)
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}
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func BenchmarkRandBytes1MiB(b *testing.B) {
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benchmarkRandBytes(b, 1024*1024)
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}
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func benchmarkRandBytes(b *testing.B, n int) {
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for i := 0; i < b.N; i++ {
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_ = RandBytes(n)
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}
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b.ReportAllocs()
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}
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