import (
    "gopkg.in/yaml.v2"
    "reflect"
    "testing"
)

func TestMapMerging(t *testing.T) {
    data := `---
world: &world
  greeting: Hello
earth:
  << : *world`

    config := map[string]interface{}{}
    err := yaml.Unmarshal([]byte(data), &config)
    if err != nil {
        t.Errorf("Failed to parse\n%v\n\ninto a %T: %v", data, config, err)
    }

    earth := config["earth"]
    expected := map[interface{}]interface{}{
        "greeting": "Hello",
    }

    if !reflect.DeepEqual(earth, expected) {
        t.Errorf("Merging does not work. Expected %v (%T), got %v (%T)", expected, expected, earth, earth)
    }
}

func TestMapSliceMerging(t *testing.T) {
    data := `---
world: &world
  greeting: Hello
earth:
  << : *world`

    config := make(yaml.MapSlice, 0)
    err := yaml.Unmarshal([]byte(data), &config)
    if err != nil {
        t.Errorf("Failed to parse\n%v\n\ninto a %T: %v", data, config, err)
    }

    earth := config[1].Value
    expected := yaml.MapSlice{{Key: "greeting", Value: "Hello"}}

    if !reflect.DeepEqual(earth, expected) {
        t.Errorf("Merging does not work. Expected %v (%T), got %v (%T)", expected, expected, earth, earth)
    }
}