Old Database Implementation.go

// database package
type DBInterface interface {
    CreateItem(Item) (*Item, error)
}

type DB struct {
    *sql.DB
}

func (db *DB) CreateItem(item Item) (*Item, error) {
    query := `INSERT INTO Table_Items(Name) VALUES(@itemName)`
    db.Query(query, sql.Named("itemName", item.Name))
  
    return &item, nil
}

type MockDB struct {}

func (db *MockDB) CreateItem(item Item) (*Item, error) {
    i := Item{Name: "Foo"}
    return &i, nil
}


// shopping cart package - import database package
type Cart struct {
    DB db.DBInterface
}

// Live implementation
db := db.DB{*sql.DB}
cartService := Cart{DB: &db}

// Mock out db when testing the cart service
db := db.MockDB{}
cartService := Cart{DB: &mockDB}