当yaml已经初始化值时，如何在Golang中测试默认值？

import (
    "testing"
    "io/ioutil"
    "gopkg.in/yaml.v2"
)

type Config struct {
    Key1 string `yaml:"key1"`
    Key2 int    `yaml:"key2"`
}

func TestDefaultValues(t *testing.T) {
    // 读取yaml文件内容
    yamlFile, err := ioutil.ReadFile("config.yaml")
    if err != nil {
        t.Fatalf("Failed to read yaml file: %v", err)
    }

    // 解析yaml内容到结构体
    var config Config
    err = yaml.Unmarshal(yamlFile, &config)
    if err != nil {
        t.Fatalf("Failed to unmarshal yaml: %v", err)
    }

    // 测试默认值
    if config.Key1 != "default value 1" {
        t.Errorf("Incorrect default value for Key1. Expected: %s, Got: %s", "default value 1", config.Key1)
    }

    if config.Key2 != 100 {
        t.Errorf("Incorrect default value for Key2. Expected: %d, Got: %d", 100, config.Key2)
    }
}

go test -v