clone_test.go

     1  // Copyright 2021 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 strings_test
     6  
     7  import (
     8  	"strings"
     9  	"testing"
    10  	"unsafe"
    11  )
    12  
    13  var emptyString string
    14  
    15  func TestClone(t *testing.T) {
    16  	var cloneTests = []string{
    17  		"",
    18  		strings.Clone(""),
    19  		strings.Repeat("a", 42)[:0],
    20  		"short",
    21  		strings.Repeat("a", 42),
    22  	}
    23  	for _, input := range cloneTests {
    24  		clone := strings.Clone(input)
    25  		if clone != input {
    26  			t.Errorf("Clone(%q) = %q; want %q", input, clone, input)
    27  		}
    28  
    29  		if len(input) != 0 && unsafe.StringData(clone) == unsafe.StringData(input) {
    30  			t.Errorf("Clone(%q) return value should not reference inputs backing memory.", input)
    31  		}
    32  
    33  		if len(input) == 0 && unsafe.StringData(clone) != unsafe.StringData(emptyString) {
    34  			t.Errorf("Clone(%#v) return value should be equal to empty string.", unsafe.StringData(input))
    35  		}
    36  	}
    37  }
    38  
    39  func BenchmarkClone(b *testing.B) {
    40  	var str = strings.Repeat("a", 42)
    41  	b.ReportAllocs()
    42  	for i := 0; i < b.N; i++ {
    43  		stringSink = strings.Clone(str)
    44  	}
    45  }
    46
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