About testing in GO

Hi all. Help plz with testing. I have a file dao.go:

package model_dao
import "io/ioutil"
const fileExtension = ".txt"
type Page struct {
    Title string
    Body  []byte
}
func (p Page) SaveAsFile() (e error) {
    p.Title = p.Title + fileExtension
    return ioutil.WriteFile(p.Title, p.Body, 0600)
}
func LoadFromFile(title string) (*Page, error) {
    fileName := title + fileExtension
    body, err := ioutil.ReadFile(fileName)
    if err != nil {
        return nil, err
    }
    return &Page{title, body}, nil
}

And a test file dao_test.go:

package model_dao_test
import (
    "shopserver/model/dao"
    "testing"
)
func TestDAOFileWorks(t *testing.T) {
    TITLE := "test"
    BODY := []byte("Hello, World!!")
    p := &model_dao.Page{TITLE, BODY}
    p.SaveAsFile()
    p, _ = model_dao.LoadFromFile(TITLE)
    result := p.Body
    if string(BODY) != string(result) {
        t.Error("Body", BODY, "saved.\n", "Load:", result)
    }
}

Here I test all 2 methods from Page, but after testing I see a message:

Tell me plz - why only 85.7%? Where he get this numbers and how to get 100%?