You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: history_test.go
    path of file: ./repos/bed/history
    
    the code of the file until where you have to start completion: package history

import (
	"strings"
	"testing"

	"github.com/itchyny/bed/buffer"
)

func TestHistoryUndo(t *testing.T) {
	history := NewHistory()
	b, index, offset, cursor, tick := history.Undo()
	if b != nil {
		t.Errorf("history.Undo should return nil buffer but got %v", b)
	}
	if index != -1 {
		t.Errorf("history.Undo should return index -1 but got %d", index)
	}
	if o
    
func TestHistoryUndo(t *testing.T) {
	history := NewHistory()
	b, index, offset, cursor, tick := history.Undo()
	if b != nil {
		t.Errorf("history.Undo should return nil buffer but got %v", b)
	}
	if index != -1 {
		t.Errorf("history.Undo should return index -1 but got %d", index)
	}
	if offset != 0 {
		t.Errorf("history.Undo should return offset 0 but got %d", offset)
	}
	if cursor != 0 {
		t.Errorf("history.Undo should return cursor 0 but got %d", cursor)
	}
	if tick != 0 {
		t.Errorf("history.Undo should return tick 0 but got %d", tick)
	}

	buffer1 := buffer.NewBuffer(strings.NewReader("test1"))
	history.Push(buffer1, 2, 1, 1)

	buffer2 := buffer.NewBuffer(strings.NewReader("test2"))
	history.Push(buffer2, 3, 2, 2)

	buf := make([]byte, 8)
	b, index, offset, cursor, tick = history.Undo()
	b.Read(buf)
	if expected := "test1\x00\x00\x00"; string(buf) != expected {
		t.Errorf("buf should be %q but got %q", expected, string(buf))
	}
	if index != 0 {
		t.Errorf("history.Undo should return index 0 but got %d", index)
	}
	if offset != 2 {
		t.Errorf("history.Undo should return offset 2 but got %d", offset)
	}
	if cursor != 1 {
		t.Errorf("history.Undo should return cursor 1 but got %d", cursor)
	}
	if tick != 1 {
		t.Errorf("history.Undo should return tick 1 but got %d", tick)
	}

	buf = make([]byte, 8)
	b, offset, cursor, tick = history.Redo()
	b.Read(buf)
	if expected := "test2\x00\x00\x00"; string(buf) != expected {
		t.Errorf("buf should be %q but got %q", expected, string(buf))
	}
	if offset != 3 {
		t.Errorf("history.Redo should return offset 3 but got %d", offset)
	}
	if cursor != 2 {
		t.Errorf("history.Redo should return cursor 2 but got %d", cursor)
	}
	if tick != 2 {
		t.Errorf("history.Redo should return cursor 2 but got %d", tick)
	}

	history.Undo()
	buffer3 := buffer.NewBuffer(strings.NewReader("test2"))
	history.Push(buffer3, 3, 2, 3)

	b, offset, cursor, tick = history.Redo()
	if b != nil {
		t.Errorf("history.Redo should return nil buffer but got %v", b)
	}
	if offset != 0 {
		t.Errorf("history.Redo should return offset 0 but got %d", offset)
	}
	if cursor != 0 {
		t.Errorf("history.Redo should return cursor 0 but got %d", cursor)
	}
	if tick != 0 {
		t.Errorf("history.Redo should return tick 0 but got %d", tick)
	}
}