Исходники и презентации

homework/strings/homework_test.go

@@ -0,0 +1,74 @@
+package main
+
+import (
+	"reflect"
+	"testing"
+	"unsafe"
+
+	"github.com/stretchr/testify/assert"
+)
+
+type COWBuffer struct {
+	data []byte
+	refs *int
+	// need to implement
+}
+
+func NewCOWBuffer(data []byte) COWBuffer {
+	return COWBuffer{} // need to implement
+}
+
+func (b *COWBuffer) Clone() COWBuffer {
+	return COWBuffer{} // need to implement
+}
+
+func (b *COWBuffer) Close() {
+	// need to implement
+}
+
+func (b *COWBuffer) Update(index int, value byte) bool {
+	return false // need to implement
+}
+
+func (b *COWBuffer) String() string {
+	return "" // need to implement
+}
+
+func TestCOWBuffer(t *testing.T) {
+	data := []byte{'a', 'b', 'c', 'd'}
+	buffer := NewCOWBuffer(data)
+	defer buffer.Close()
+
+	copy1 := buffer.Clone()
+	copy2 := buffer.Clone()
+
+	assert.Equal(t, unsafe.SliceData(data), unsafe.SliceData(buffer.data))
+	assert.Equal(t, unsafe.SliceData(buffer.data), unsafe.SliceData(copy1.data))
+	assert.Equal(t, unsafe.SliceData(copy1.data), unsafe.SliceData(copy2.data))
+
+	assert.True(t, (*byte)(unsafe.SliceData(data)) == unsafe.StringData(buffer.String()))
+	assert.True(t, (*byte)(unsafe.StringData(buffer.String())) == unsafe.StringData(copy1.String()))
+	assert.True(t, (*byte)(unsafe.StringData(copy1.String())) == unsafe.StringData(copy2.String()))
+
+	assert.True(t, buffer.Update(0, 'g'))
+	assert.False(t, buffer.Update(-1, 'g'))
+	assert.False(t, buffer.Update(4, 'g'))
+
+	assert.True(t, reflect.DeepEqual([]byte{'g', 'b', 'c', 'd'}, buffer.data))
+	assert.True(t, reflect.DeepEqual([]byte{'a', 'b', 'c', 'd'}, copy1.data))
+	assert.True(t, reflect.DeepEqual([]byte{'a', 'b', 'c', 'd'}, copy2.data))
+
+	assert.NotEqual(t, unsafe.SliceData(buffer.data), unsafe.SliceData(copy1.data))
+	assert.Equal(t, unsafe.SliceData(copy1.data), unsafe.SliceData(copy2.data))
+
+	copy1.Close()
+
+	previous := copy2.data
+	copy2.Update(0, 'f')
+	current := copy2.data
+
+	// 1 reference - don't need to copy buffer during update
+	assert.Equal(t, unsafe.SliceData(previous), unsafe.SliceData(current))
+
+	copy2.Close()
+}