golang slice_test 代码
文件路径：/src/cmd/compile/internal/test/testdata/slice_test.go
/ Copyright 2018 The Go Authors. All rights reserved.
/ Use of this source code is governed by a BSD-style
/ license that can be found in the LICENSE file.
/ This test makes sure that t.s = t.s[0:x] doesn't write
/ either the slice pointer or the capacity.
/ See issue #14855.
package main
import "testing"
const N = 1000000
type X struct {
s []int
}
func TestSlice(t *testing.T) {
done := make(chan struct{})
a := make([]int, N+10)
x := &X{a}
go func() {
for i := 0; i < N; i++ {
x.s = x.s[1:9]
}
done <- struct{}{}
}()
go func() {
for i := 0; i < N; i++ {
x.s = x.s[0:8] / should only write len
}
done <- struct{}{}
}()
<-done
<-done
if cap(x.s) != cap(a)-N {
t.Errorf("wanted cap=%d, got %d\n", cap(a)-N, cap(x.s))
}
if &x.s[0] != &a[N] {
t.Errorf("wanted ptr=%p, got %p\n", &a[N], &x.s[0])
}
}