sizeof_test.go

Documentation: runtime

		 1  // Copyright 2018 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 runtime_test
		 6  
		 7  import (
		 8  	"reflect"
		 9  	"runtime"
		10  	"testing"
		11  	"unsafe"
		12  )
		13  
		14  // Assert that the size of important structures do not change unexpectedly.
		15  
		16  func TestSizeof(t *testing.T) {
		17  	const _64bit = unsafe.Sizeof(uintptr(0)) == 8
		18  
		19  	var tests = []struct {
		20  		val		interface{} // type as a value
		21  		_32bit uintptr		 // size on 32bit platforms
		22  		_64bit uintptr		 // size on 64bit platforms
		23  	}{
		24  		{runtime.G{}, 236, 392},	 // g, but exported for testing
		25  		{runtime.Sudog{}, 56, 88}, // sudog, but exported for testing
		26  	}
		27  
		28  	for _, tt := range tests {
		29  		want := tt._32bit
		30  		if _64bit {
		31  			want = tt._64bit
		32  		}
		33  		got := reflect.TypeOf(tt.val).Size()
		34  		if want != got {
		35  			t.Errorf("unsafe.Sizeof(%T) = %d, want %d", tt.val, got, want)
		36  		}
		37  	}
		38  }
		39
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