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116 lines
2.4 KiB

package rand
import (
"bytes"
"encoding/json"
"fmt"
mrand "math/rand"
"sync"
"testing"
"time"
"github.com/stretchr/testify/assert"
)
func TestRandStr(t *testing.T) {
l := 243
s := Str(l)
assert.Equal(t, l, len(s))
}
func TestRandBytes(t *testing.T) {
l := 243
b := Bytes(l)
assert.Equal(t, l, len(b))
}
func TestRandIntn(t *testing.T) {
n := 243
for i := 0; i < 100; i++ {
x := Intn(n)
assert.True(t, x < n)
}
}
// Test to make sure that we never call math.rand().
// We do this by ensuring that outputs are deterministic.
func TestDeterminism(t *testing.T) {
var firstOutput string
// Set math/rand's seed for the sake of debugging this test.
// (It isn't strictly necessary).
mrand.Seed(1)
for i := 0; i < 100; i++ {
output := testThemAll()
if i == 0 {
firstOutput = output
} else if firstOutput != output {
t.Errorf("run #%d's output was different from first run.\nfirst: %v\nlast: %v",
i, firstOutput, output)
}
}
}
func testThemAll() string {
// Such determinism.
grand.reset(1)
// Use it.
out := new(bytes.Buffer)
perm := Perm(10)
blob, _ := json.Marshal(perm)
fmt.Fprintf(out, "perm: %s\n", blob)
fmt.Fprintf(out, "randInt: %d\n", Int())
fmt.Fprintf(out, "randUint: %d\n", Uint())
fmt.Fprintf(out, "randIntn: %d\n", Intn(97))
fmt.Fprintf(out, "randInt31: %d\n", Int31())
fmt.Fprintf(out, "randInt32: %d\n", Int32())
fmt.Fprintf(out, "randInt63: %d\n", Int63())
fmt.Fprintf(out, "randInt64: %d\n", Int64())
fmt.Fprintf(out, "randUint32: %d\n", Uint32())
fmt.Fprintf(out, "randUint64: %d\n", Uint64())
return out.String()
}
func TestRngConcurrencySafety(t *testing.T) {
var wg sync.WaitGroup
for i := 0; i < 100; i++ {
wg.Add(1)
go func() {
defer wg.Done()
_ = Uint64()
<-time.After(time.Millisecond * time.Duration(Intn(100)))
_ = Perm(3)
}()
}
wg.Wait()
}
func BenchmarkRandBytes10B(b *testing.B) {
benchmarkRandBytes(b, 10)
}
func BenchmarkRandBytes100B(b *testing.B) {
benchmarkRandBytes(b, 100)
}
func BenchmarkRandBytes1KiB(b *testing.B) {
benchmarkRandBytes(b, 1024)
}
func BenchmarkRandBytes10KiB(b *testing.B) {
benchmarkRandBytes(b, 10*1024)
}
func BenchmarkRandBytes100KiB(b *testing.B) {
benchmarkRandBytes(b, 100*1024)
}
func BenchmarkRandBytes1MiB(b *testing.B) {
benchmarkRandBytes(b, 1024*1024)
}
func benchmarkRandBytes(b *testing.B, n int) {
for i := 0; i < b.N; i++ {
_ = Bytes(n)
}
b.ReportAllocs()
}