race_test.go

Documentation: math/rand

		 1  // Copyright 2016 The Go Authors. All rights reserved.
		 2  // Use of this source code is governed by a BSD-style
		 3  // license that can be found in the LICENSE file.
		 4  
		 5  package rand_test
		 6  
		 7  import (
		 8  	. "math/rand"
		 9  	"sync"
		10  	"testing"
		11  )
		12  
		13  // TestConcurrent exercises the rand API concurrently, triggering situations
		14  // where the race detector is likely to detect issues.
		15  func TestConcurrent(t *testing.T) {
		16  	const (
		17  		numRoutines = 10
		18  		numCycles	 = 10
		19  	)
		20  	var wg sync.WaitGroup
		21  	defer wg.Wait()
		22  	wg.Add(numRoutines)
		23  	for i := 0; i < numRoutines; i++ {
		24  		go func(i int) {
		25  			defer wg.Done()
		26  			buf := make([]byte, 997)
		27  			for j := 0; j < numCycles; j++ {
		28  				var seed int64
		29  				seed += int64(ExpFloat64())
		30  				seed += int64(Float32())
		31  				seed += int64(Float64())
		32  				seed += int64(Intn(Int()))
		33  				seed += int64(Int31n(Int31()))
		34  				seed += int64(Int63n(Int63()))
		35  				seed += int64(NormFloat64())
		36  				seed += int64(Uint32())
		37  				seed += int64(Uint64())
		38  				for _, p := range Perm(10) {
		39  					seed += int64(p)
		40  				}
		41  				Read(buf)
		42  				for _, b := range buf {
		43  					seed += int64(b)
		44  				}
		45  				Seed(int64(i*j) * seed)
		46  			}
		47  		}(i)
		48  	}
		49  }
		50
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